Add m-esr52 at 52.6.0

13 files changed, 5803 insertions, 0 deletions

diff --git a/dom/media/ogg/OggCodecState.cpp b/dom/media/ogg/OggCodecState.cpp
new file mode 100644
index 0000000000..6830639e89
--- /dev/null
+++ b/dom/media/ogg/OggCodecState.cpp
@@ -0,0 +1,1839 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim:set ts=2 sw=2 sts=2 et cindent: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include <string.h>
+
+#include "mozilla/EndianUtils.h"
+#include <stdint.h>
+
+#include "nsDebug.h"
+#include "OggCodecState.h"
+#include "OpusParser.h"
+#include "VideoUtils.h"
+#include <algorithm>
+
+#include <opus/opus.h>
+#include "opus/opus_multistream.h"
+
+// On Android JellyBean, the hardware.h header redefines version_major and
+// version_minor, which breaks our build.  See:
+// https://bugzilla.mozilla.org/show_bug.cgi?id=912702#c6
+#ifdef MOZ_WIDGET_GONK
+#ifdef version_major
+#undef version_major
+#endif
+#ifdef version_minor
+#undef version_minor
+#endif
+#endif
+
+namespace mozilla {
+
+extern LazyLogModule gMediaDecoderLog;
+#define LOG(type, msg) MOZ_LOG(gMediaDecoderLog, type, msg)
+
+/** Decoder base class for Ogg-encapsulated streams. */
+OggCodecState*
+OggCodecState::Create(ogg_page* aPage)
+{
+  NS_ASSERTION(ogg_page_bos(aPage), "Only call on BOS page!");
+  nsAutoPtr<OggCodecState> codecState;
+  if (aPage->body_len > 6 && memcmp(aPage->body+1, "theora", 6) == 0) {
+    codecState = new TheoraState(aPage);
+  } else if (aPage->body_len > 6 && memcmp(aPage->body+1, "vorbis", 6) == 0) {
+    codecState = new VorbisState(aPage);
+  } else if (aPage->body_len > 8 && memcmp(aPage->body, "OpusHead", 8) == 0) {
+    codecState = new OpusState(aPage);
+  } else if (aPage->body_len > 8 && memcmp(aPage->body, "fishead\0", 8) == 0) {
+    codecState = new SkeletonState(aPage);
+  } else if (aPage->body_len > 5 && memcmp(aPage->body, "\177FLAC", 5) == 0) {
+    codecState = new FlacState(aPage);
+  } else {
+    codecState = new OggCodecState(aPage, false);
+  }
+  return codecState->OggCodecState::InternalInit() ? codecState.forget() : nullptr;
+}
+
+OggCodecState::OggCodecState(ogg_page* aBosPage, bool aActive)
+  : mPacketCount(0)
+  , mSerial(ogg_page_serialno(aBosPage))
+  , mActive(aActive)
+  , mDoneReadingHeaders(!aActive)
+{
+  MOZ_COUNT_CTOR(OggCodecState);
+  memset(&mState, 0, sizeof(ogg_stream_state));
+}
+
+OggCodecState::~OggCodecState()
+{
+  MOZ_COUNT_DTOR(OggCodecState);
+  Reset();
+#ifdef DEBUG
+  int ret =
+#endif
+  ogg_stream_clear(&mState);
+  NS_ASSERTION(ret == 0, "ogg_stream_clear failed");
+}
+
+nsresult
+OggCodecState::Reset()
+{
+  if (ogg_stream_reset(&mState) != 0) {
+    return NS_ERROR_FAILURE;
+  }
+  mPackets.Erase();
+  ClearUnstamped();
+  return NS_OK;
+}
+
+void
+OggCodecState::ClearUnstamped()
+{
+  for (uint32_t i = 0; i < mUnstamped.Length(); ++i) {
+    OggCodecState::ReleasePacket(mUnstamped[i]);
+  }
+  mUnstamped.Clear();
+}
+
+bool
+OggCodecState::InternalInit()
+{
+  int ret = ogg_stream_init(&mState, mSerial);
+  return ret == 0;
+}
+
+bool
+OggCodecState::IsValidVorbisTagName(nsCString& aName)
+{
+  // Tag names must consist of ASCII 0x20 through 0x7D,
+  // excluding 0x3D '=' which is the separator.
+  uint32_t length = aName.Length();
+  const char* data = aName.Data();
+  for (uint32_t i = 0; i < length; i++) {
+    if (data[i] < 0x20 || data[i] > 0x7D || data[i] == '=') {
+      return false;
+    }
+  }
+  return true;
+}
+
+bool
+OggCodecState::AddVorbisComment(MetadataTags* aTags,
+                                const char* aComment,
+                                uint32_t aLength)
+{
+  const char* div = (const char*)memchr(aComment, '=', aLength);
+  if (!div) {
+    LOG(LogLevel::Debug, ("Skipping comment: no separator"));
+    return false;
+  }
+  nsCString key = nsCString(aComment, div-aComment);
+  if (!IsValidVorbisTagName(key)) {
+    LOG(LogLevel::Debug, ("Skipping comment: invalid tag name"));
+    return false;
+  }
+  uint32_t valueLength = aLength - (div-aComment);
+  nsCString value = nsCString(div + 1, valueLength);
+  if (!IsUTF8(value)) {
+    LOG(LogLevel::Debug, ("Skipping comment: invalid UTF-8 in value"));
+    return false;
+  }
+  aTags->Put(key, value);
+  return true;
+}
+
+void
+VorbisState::RecordVorbisPacketSamples(ogg_packet* aPacket, long aSamples)
+{
+#ifdef VALIDATE_VORBIS_SAMPLE_CALCULATION
+  mVorbisPacketSamples[aPacket] = aSamples;
+#endif
+}
+
+void
+VorbisState::ValidateVorbisPacketSamples(ogg_packet* aPacket, long aSamples)
+{
+#ifdef VALIDATE_VORBIS_SAMPLE_CALCULATION
+  NS_ASSERTION(mVorbisPacketSamples[aPacket] == aSamples,
+    "Decoded samples for Vorbis packet don't match expected!");
+  mVorbisPacketSamples.erase(aPacket);
+#endif
+}
+
+void
+VorbisState::AssertHasRecordedPacketSamples(ogg_packet* aPacket)
+{
+#ifdef VALIDATE_VORBIS_SAMPLE_CALCULATION
+  NS_ASSERTION(mVorbisPacketSamples.count(aPacket) == 1,
+    "Must have recorded packet samples");
+#endif
+}
+
+static ogg_packet*
+Clone(ogg_packet* aPacket)
+{
+  ogg_packet* p = new ogg_packet();
+  memcpy(p, aPacket, sizeof(ogg_packet));
+  p->packet = new unsigned char[p->bytes];
+  memcpy(p->packet, aPacket->packet, p->bytes);
+  return p;
+}
+
+void
+OggCodecState::ReleasePacket(ogg_packet* aPacket)
+{
+  if (aPacket)
+    delete [] aPacket->packet;
+  delete aPacket;
+}
+
+void
+OggPacketQueue::Append(ogg_packet* aPacket)
+{
+  nsDeque::Push(aPacket);
+}
+
+bool
+OggCodecState::IsPacketReady()
+{
+  return !mPackets.IsEmpty();
+}
+
+ogg_packet*
+OggCodecState::PacketOut()
+{
+  if (mPackets.IsEmpty()) {
+    return nullptr;
+  }
+  return mPackets.PopFront();
+}
+
+ogg_packet*
+OggCodecState::PacketPeek()
+{
+  if (mPackets.IsEmpty()) {
+    return nullptr;
+  }
+  return mPackets.PeekFront();
+}
+
+void
+OggCodecState::PushFront(OggPacketQueue &&aOther)
+{
+  while (!aOther.IsEmpty()) {
+    mPackets.PushFront(aOther.Pop());
+  }
+}
+
+already_AddRefed<MediaRawData>
+OggCodecState::PacketOutAsMediaRawData()
+{
+  ogg_packet* packet = PacketOut();
+  if (!packet) {
+    return nullptr;
+  }
+
+  NS_ASSERTION(!IsHeader(packet), "PacketOutAsMediaRawData can only be called on non-header packets");
+  RefPtr<MediaRawData> sample = new MediaRawData(packet->packet, packet->bytes);
+  if (packet->bytes && !sample->Data()) {
+    // OOM.
+    ReleasePacket(packet);
+    return nullptr;
+  }
+
+  int64_t end_tstamp = Time(packet->granulepos);
+  NS_ASSERTION(end_tstamp >= 0, "timestamp invalid");
+
+  int64_t duration = PacketDuration(packet);
+  NS_ASSERTION(duration >= 0, "duration invalid");
+
+  sample->mTimecode = packet->granulepos;
+  sample->mTime = end_tstamp - duration;
+  sample->mDuration = duration;
+  sample->mKeyframe = IsKeyframe(packet);
+  sample->mEOS = packet->e_o_s;
+
+  ReleasePacket(packet);
+
+  return sample.forget();
+}
+
+nsresult
+OggCodecState::PageIn(ogg_page* aPage)
+{
+  if (!mActive) {
+    return NS_OK;
+  }
+  NS_ASSERTION(static_cast<uint32_t>(ogg_page_serialno(aPage)) == mSerial,
+               "Page must be for this stream!");
+  if (ogg_stream_pagein(&mState, aPage) == -1) {
+    return NS_ERROR_FAILURE;
+  }
+  int r;
+  do {
+    ogg_packet packet;
+    r = ogg_stream_packetout(&mState, &packet);
+    if (r == 1) {
+      mPackets.Append(Clone(&packet));
+    }
+  } while (r != 0);
+  if (ogg_stream_check(&mState)) {
+    NS_WARNING("Unrecoverable error in ogg_stream_packetout");
+    return NS_ERROR_FAILURE;
+  }
+  return NS_OK;
+}
+
+nsresult
+OggCodecState::PacketOutUntilGranulepos(bool& aFoundGranulepos)
+{
+  int r;
+  aFoundGranulepos = false;
+  // Extract packets from the sync state until either no more packets
+  // come out, or we get a data packet with non -1 granulepos.
+  do {
+    ogg_packet packet;
+    r = ogg_stream_packetout(&mState, &packet);
+    if (r == 1) {
+      ogg_packet* clone = Clone(&packet);
+      if (IsHeader(&packet)) {
+        // Header packets go straight into the packet queue.
+        mPackets.Append(clone);
+      } else {
+        // We buffer data packets until we encounter a granulepos. We'll
+        // then use the granulepos to figure out the granulepos of the
+        // preceeding packets.
+        mUnstamped.AppendElement(clone);
+        aFoundGranulepos = packet.granulepos > 0;
+      }
+    }
+  } while (r != 0 && !aFoundGranulepos);
+  if (ogg_stream_check(&mState)) {
+    NS_WARNING("Unrecoverable error in ogg_stream_packetout");
+    return NS_ERROR_FAILURE;
+  }
+  return NS_OK;
+}
+
+TheoraState::TheoraState(ogg_page* aBosPage)
+  : OggCodecState(aBosPage, true)
+  , mSetup(0)
+  , mCtx(0)
+  , mPixelAspectRatio(0)
+{
+  MOZ_COUNT_CTOR(TheoraState);
+  th_info_init(&mInfo);
+  th_comment_init(&mComment);
+}
+
+TheoraState::~TheoraState()
+{
+  MOZ_COUNT_DTOR(TheoraState);
+  th_setup_free(mSetup);
+  th_decode_free(mCtx);
+  th_comment_clear(&mComment);
+  th_info_clear(&mInfo);
+}
+
+bool
+TheoraState::Init()
+{
+  if (!mActive) {
+    return false;
+  }
+
+  int64_t n = mInfo.aspect_numerator;
+  int64_t d = mInfo.aspect_denominator;
+
+  mPixelAspectRatio = (n == 0 || d == 0)
+    ? 1.0f : static_cast<float>(n) / static_cast<float>(d);
+
+  // Ensure the frame and picture regions aren't larger than our prescribed
+  // maximum, or zero sized.
+  nsIntSize frame(mInfo.frame_width, mInfo.frame_height);
+  nsIntRect picture(mInfo.pic_x, mInfo.pic_y, mInfo.pic_width, mInfo.pic_height);
+  if (!IsValidVideoRegion(frame, picture, frame)) {
+    return mActive = false;
+  }
+
+  mCtx = th_decode_alloc(&mInfo, mSetup);
+  if (!mCtx) {
+    return mActive = false;
+  }
+
+  return true;
+}
+
+bool
+TheoraState::DecodeHeader(ogg_packet* aPacket)
+{
+  nsAutoRef<ogg_packet> autoRelease(aPacket);
+  mPacketCount++;
+  int ret = th_decode_headerin(&mInfo,
+                               &mComment,
+                               &mSetup,
+                               aPacket);
+
+  // We must determine when we've read the last header packet.
+  // th_decode_headerin() does not tell us when it's read the last header, so
+  // we must keep track of the headers externally.
+  //
+  // There are 3 header packets, the Identification, Comment, and Setup
+  // headers, which must be in that order. If they're out of order, the file
+  // is invalid. If we've successfully read a header, and it's the setup
+  // header, then we're done reading headers. The first byte of each packet
+  // determines it's type as follows:
+  //    0x80 -> Identification header
+  //    0x81 -> Comment header
+  //    0x82 -> Setup header
+  // See http://www.theora.org/doc/Theora.pdf Chapter 6, "Bitstream Headers",
+  // for more details of the Ogg/Theora containment scheme.
+  bool isSetupHeader = aPacket->bytes > 0 && aPacket->packet[0] == 0x82;
+  if (ret < 0 || mPacketCount > 3) {
+    // We've received an error, or the first three packets weren't valid
+    // header packets. Assume bad input.
+    // Our caller will deactivate the bitstream.
+    return false;
+  } else if (ret > 0 && isSetupHeader && mPacketCount == 3) {
+    // Successfully read the three header packets.
+    mDoneReadingHeaders = true;
+  }
+  return true;
+}
+
+int64_t
+TheoraState::Time(int64_t granulepos)
+{
+  if (!mActive) {
+    return -1;
+  }
+  return TheoraState::Time(&mInfo, granulepos);
+}
+
+bool
+TheoraState::IsHeader(ogg_packet* aPacket)
+{
+  return th_packet_isheader(aPacket);
+}
+
+# define TH_VERSION_CHECK(_info,_maj,_min,_sub) \
+ (((_info)->version_major>(_maj)||(_info)->version_major==(_maj))&& \
+ (((_info)->version_minor>(_min)||(_info)->version_minor==(_min))&& \
+ (_info)->version_subminor>=(_sub)))
+
+int64_t
+TheoraState::Time(th_info* aInfo, int64_t aGranulepos)
+{
+  if (aGranulepos < 0 || aInfo->fps_numerator == 0) {
+    return -1;
+  }
+  // Implementation of th_granule_frame inlined here to operate
+  // on the th_info structure instead of the theora_state.
+  int shift = aInfo->keyframe_granule_shift;
+  ogg_int64_t iframe = aGranulepos >> shift;
+  ogg_int64_t pframe = aGranulepos - (iframe << shift);
+  int64_t frameno = iframe + pframe - TH_VERSION_CHECK(aInfo, 3, 2, 1);
+  CheckedInt64 t =
+    ((CheckedInt64(frameno) + 1) * USECS_PER_S) * aInfo->fps_denominator;
+  if (!t.isValid()) {
+    return -1;
+  }
+  t /= aInfo->fps_numerator;
+  return t.isValid() ? t.value() : -1;
+}
+
+int64_t TheoraState::StartTime(int64_t granulepos)
+{
+  if (granulepos < 0 || !mActive || mInfo.fps_numerator == 0) {
+    return -1;
+  }
+  CheckedInt64 t =
+    (CheckedInt64(th_granule_frame(mCtx, granulepos)) * USECS_PER_S)
+    * mInfo.fps_denominator;
+  if (!t.isValid()) {
+    return -1;
+  }
+  return t.value() / mInfo.fps_numerator;
+}
+
+int64_t
+TheoraState::PacketDuration(ogg_packet* aPacket)
+{
+  if (!mActive || mInfo.fps_numerator == 0) {
+    return -1;
+  }
+  CheckedInt64 t =
+    SaferMultDiv(mInfo.fps_denominator, USECS_PER_S, mInfo.fps_numerator);
+  return t.isValid() ? t.value() : -1;
+}
+
+int64_t
+TheoraState::MaxKeyframeOffset()
+{
+  // Determine the maximum time in microseconds by which a key frame could
+  // offset for the theora bitstream. Theora granulepos encode time as:
+  // ((key_frame_number << granule_shift) + frame_offset).
+  // Therefore the maximum possible time by which any frame could be offset
+  // from a keyframe is the duration of (1 << granule_shift) - 1) frames.
+  int64_t frameDuration;
+
+  // Max number of frames keyframe could possibly be offset.
+  int64_t keyframeDiff = (1 << mInfo.keyframe_granule_shift) - 1;
+
+  // Length of frame in usecs.
+  frameDuration = (mInfo.fps_denominator * USECS_PER_S) / mInfo.fps_numerator;
+
+  // Total time in usecs keyframe can be offset from any given frame.
+  return frameDuration * keyframeDiff;
+}
+
+bool
+TheoraState::IsKeyframe(ogg_packet* pkt)
+{
+  // first bit of packet is 1 for header, 0 for data
+  // second bit of packet is 1 for inter frame, 0 for intra frame
+  return (pkt->bytes >= 1 && (pkt->packet[0] & 0x40) == 0x00);
+}
+
+nsresult
+TheoraState::PageIn(ogg_page* aPage)
+{
+  if (!mActive)
+    return NS_OK;
+  NS_ASSERTION(static_cast<uint32_t>(ogg_page_serialno(aPage)) == mSerial,
+               "Page must be for this stream!");
+  if (ogg_stream_pagein(&mState, aPage) == -1)
+    return NS_ERROR_FAILURE;
+  bool foundGp;
+  nsresult res = PacketOutUntilGranulepos(foundGp);
+  if (NS_FAILED(res))
+    return res;
+  if (foundGp && mDoneReadingHeaders) {
+    // We've found a packet with a granulepos, and we've loaded our metadata
+    // and initialized our decoder. Determine granulepos of buffered packets.
+    ReconstructTheoraGranulepos();
+    for (uint32_t i = 0; i < mUnstamped.Length(); ++i) {
+      ogg_packet* packet = mUnstamped[i];
+#ifdef DEBUG
+      NS_ASSERTION(!IsHeader(packet), "Don't try to recover header packet gp");
+      NS_ASSERTION(packet->granulepos != -1, "Packet must have gp by now");
+#endif
+      mPackets.Append(packet);
+    }
+    mUnstamped.Clear();
+  }
+  return NS_OK;
+}
+
+// Returns 1 if the Theora info struct is decoding a media of Theora
+// version (maj,min,sub) or later, otherwise returns 0.
+int
+TheoraVersion(th_info* info,
+              unsigned char maj,
+              unsigned char min,
+              unsigned char sub)
+{
+  ogg_uint32_t ver = (maj << 16) + (min << 8) + sub;
+  ogg_uint32_t th_ver = (info->version_major << 16) +
+                        (info->version_minor << 8) +
+                        info->version_subminor;
+  return (th_ver >= ver) ? 1 : 0;
+}
+
+void
+TheoraState::ReconstructTheoraGranulepos()
+{
+  if (mUnstamped.Length() == 0) {
+    return;
+  }
+  ogg_int64_t lastGranulepos = mUnstamped[mUnstamped.Length() - 1]->granulepos;
+  NS_ASSERTION(lastGranulepos != -1, "Must know last granulepos");
+
+  // Reconstruct the granulepos (and thus timestamps) of the decoded
+  // frames. Granulepos are stored as ((keyframe<<shift)+offset). We
+  // know the granulepos of the last frame in the list, so we can infer
+  // the granulepos of the intermediate frames using their frame numbers.
+  ogg_int64_t shift = mInfo.keyframe_granule_shift;
+  ogg_int64_t version_3_2_1 = TheoraVersion(&mInfo,3,2,1);
+  ogg_int64_t lastFrame = th_granule_frame(mCtx,
+                                           lastGranulepos) + version_3_2_1;
+  ogg_int64_t firstFrame = lastFrame - mUnstamped.Length() + 1;
+
+  // Until we encounter a keyframe, we'll assume that the "keyframe"
+  // segment of the granulepos is the first frame, or if that causes
+  // the "offset" segment to overflow, we assume the required
+  // keyframe is maximumally offset. Until we encounter a keyframe
+  // the granulepos will probably be wrong, but we can't decode the
+  // frame anyway (since we don't have its keyframe) so it doesn't really
+  // matter.
+  ogg_int64_t keyframe = lastGranulepos >> shift;
+
+  // The lastFrame, firstFrame, keyframe variables, as well as the frame
+  // variable in the loop below, store the frame number for Theora
+  // version >= 3.2.1 streams, and store the frame index for Theora
+  // version < 3.2.1 streams.
+  for (uint32_t i = 0; i < mUnstamped.Length() - 1; ++i) {
+    ogg_int64_t frame = firstFrame + i;
+    ogg_int64_t granulepos;
+    ogg_packet* packet = mUnstamped[i];
+    bool isKeyframe = th_packet_iskeyframe(packet) == 1;
+
+    if (isKeyframe) {
+      granulepos = frame << shift;
+      keyframe = frame;
+    } else if (frame >= keyframe &&
+                frame - keyframe < ((ogg_int64_t)1 << shift))
+    {
+      // (frame - keyframe) won't overflow the "offset" segment of the
+      // granulepos, so it's safe to calculate the granulepos.
+      granulepos = (keyframe << shift) + (frame - keyframe);
+    } else {
+      // (frame - keyframeno) will overflow the "offset" segment of the
+      // granulepos, so we take "keyframe" to be the max possible offset
+      // frame instead.
+      ogg_int64_t k = std::max(frame - (((ogg_int64_t)1 << shift) - 1), version_3_2_1);
+      granulepos = (k << shift) + (frame - k);
+    }
+    // Theora 3.2.1+ granulepos store frame number [1..N], so granulepos
+    // should be > 0.
+    // Theora 3.2.0 granulepos store the frame index [0..(N-1)], so
+    // granulepos should be >= 0.
+    NS_ASSERTION(granulepos >= version_3_2_1,
+                  "Invalid granulepos for Theora version");
+
+    // Check that the frame's granule number is one more than the
+    // previous frame's.
+    NS_ASSERTION(i == 0 ||
+                 th_granule_frame(mCtx, granulepos) ==
+                 th_granule_frame(mCtx, mUnstamped[i-1]->granulepos) + 1,
+                 "Granulepos calculation is incorrect!");
+
+    packet->granulepos = granulepos;
+  }
+
+  // Check that the second to last frame's granule number is one less than
+  // the last frame's (the known granule number). If not our granulepos
+  // recovery missed a beat.
+  NS_ASSERTION(mUnstamped.Length() < 2 ||
+    th_granule_frame(mCtx, mUnstamped[mUnstamped.Length()-2]->granulepos) + 1 ==
+    th_granule_frame(mCtx, lastGranulepos),
+    "Granulepos recovery should catch up with packet->granulepos!");
+}
+
+nsresult
+VorbisState::Reset()
+{
+  nsresult res = NS_OK;
+  if (mActive && vorbis_synthesis_restart(&mDsp) != 0) {
+    res = NS_ERROR_FAILURE;
+  }
+  if (NS_FAILED(OggCodecState::Reset())) {
+    return NS_ERROR_FAILURE;
+  }
+
+  mGranulepos = 0;
+  mPrevVorbisBlockSize = 0;
+
+  return res;
+}
+
+VorbisState::VorbisState(ogg_page* aBosPage)
+  : OggCodecState(aBosPage, true)
+  , mPrevVorbisBlockSize(0)
+  , mGranulepos(0)
+{
+  MOZ_COUNT_CTOR(VorbisState);
+  vorbis_info_init(&mInfo);
+  vorbis_comment_init(&mComment);
+  memset(&mDsp, 0, sizeof(vorbis_dsp_state));
+  memset(&mBlock, 0, sizeof(vorbis_block));
+}
+
+VorbisState::~VorbisState()
+{
+  MOZ_COUNT_DTOR(VorbisState);
+  Reset();
+  vorbis_block_clear(&mBlock);
+  vorbis_dsp_clear(&mDsp);
+  vorbis_info_clear(&mInfo);
+  vorbis_comment_clear(&mComment);
+}
+
+bool
+VorbisState::DecodeHeader(ogg_packet* aPacket)
+{
+  nsAutoRef<ogg_packet> autoRelease(aPacket);
+  mPacketCount++;
+  int ret = vorbis_synthesis_headerin(&mInfo,
+                                      &mComment,
+                                      aPacket);
+  // We must determine when we've read the last header packet.
+  // vorbis_synthesis_headerin() does not tell us when it's read the last
+  // header, so we must keep track of the headers externally.
+  //
+  // There are 3 header packets, the Identification, Comment, and Setup
+  // headers, which must be in that order. If they're out of order, the file
+  // is invalid. If we've successfully read a header, and it's the setup
+  // header, then we're done reading headers. The first byte of each packet
+  // determines it's type as follows:
+  //    0x1 -> Identification header
+  //    0x3 -> Comment header
+  //    0x5 -> Setup header
+  // For more details of the Vorbis/Ogg containment scheme, see the Vorbis I
+  // Specification, Chapter 4, Codec Setup and Packet Decode:
+  // http://www.xiph.org/vorbis/doc/Vorbis_I_spec.html#x1-580004
+
+  bool isSetupHeader = aPacket->bytes > 0 && aPacket->packet[0] == 0x5;
+
+  if (ret < 0 || mPacketCount > 3) {
+    // We've received an error, or the first three packets weren't valid
+    // header packets. Assume bad input. Our caller will deactivate the
+    // bitstream.
+    return false;
+  } else if (ret == 0 && isSetupHeader && mPacketCount == 3) {
+    // Successfully read the three header packets.
+    // The bitstream remains active.
+    mDoneReadingHeaders = true;
+  }
+  return true;
+}
+
+bool
+VorbisState::Init()
+{
+  if (!mActive) {
+    return false;
+  }
+
+  int ret = vorbis_synthesis_init(&mDsp, &mInfo);
+  if (ret != 0) {
+    NS_WARNING("vorbis_synthesis_init() failed initializing vorbis bitstream");
+    return mActive = false;
+  }
+  ret = vorbis_block_init(&mDsp, &mBlock);
+  if (ret != 0) {
+    NS_WARNING("vorbis_block_init() failed initializing vorbis bitstream");
+    if (mActive) {
+      vorbis_dsp_clear(&mDsp);
+    }
+    return mActive = false;
+  }
+  return true;
+}
+
+int64_t
+VorbisState::Time(int64_t granulepos)
+{
+  if (!mActive) {
+    return -1;
+  }
+
+  return VorbisState::Time(&mInfo, granulepos);
+}
+
+int64_t
+VorbisState::Time(vorbis_info* aInfo, int64_t aGranulepos)
+{
+  if (aGranulepos == -1 || aInfo->rate == 0) {
+    return -1;
+  }
+  CheckedInt64 t = SaferMultDiv(aGranulepos, USECS_PER_S, aInfo->rate);
+  return t.isValid() ? t.value() : 0;
+}
+
+int64_t
+VorbisState::PacketDuration(ogg_packet* aPacket)
+{
+  if (!mActive) {
+    return -1;
+  }
+  if (aPacket->granulepos == -1) {
+    return -1;
+  }
+  // @FIXME store these in a more stable place
+  if (mVorbisPacketSamples.count(aPacket) == 0) {
+    // We haven't seen this packet, don't know its size?
+    return -1;
+  }
+
+  long samples = mVorbisPacketSamples[aPacket];
+  return Time(samples);
+}
+
+bool
+VorbisState::IsHeader(ogg_packet* aPacket)
+{
+  // The first byte in each Vorbis header packet is either 0x01, 0x03, or 0x05,
+  // i.e. the first bit is odd. Audio data packets have their first bit as 0x0.
+  // Any packet with its first bit set cannot be a data packet, it's a
+  // (possibly invalid) header packet.
+  // See: http://xiph.org/vorbis/doc/Vorbis_I_spec.html#x1-610004.2.1
+  return aPacket->bytes > 0 ? (aPacket->packet[0] & 0x1) : false;
+}
+
+MetadataTags*
+VorbisState::GetTags()
+{
+  MetadataTags* tags;
+  NS_ASSERTION(mComment.user_comments, "no vorbis comment strings!");
+  NS_ASSERTION(mComment.comment_lengths, "no vorbis comment lengths!");
+  tags = new MetadataTags;
+  for (int i = 0; i < mComment.comments; i++) {
+    AddVorbisComment(tags, mComment.user_comments[i],
+                     mComment.comment_lengths[i]);
+  }
+  return tags;
+}
+
+nsresult
+VorbisState::PageIn(ogg_page* aPage)
+{
+  if (!mActive) {
+    return NS_OK;
+  }
+  NS_ASSERTION(static_cast<uint32_t>(ogg_page_serialno(aPage)) == mSerial,
+               "Page must be for this stream!");
+  if (ogg_stream_pagein(&mState, aPage) == -1)
+    return NS_ERROR_FAILURE;
+  bool foundGp;
+  nsresult res = PacketOutUntilGranulepos(foundGp);
+  if (NS_FAILED(res)) {
+    return res;
+  }
+  if (foundGp && mDoneReadingHeaders) {
+    // We've found a packet with a granulepos, and we've loaded our metadata
+    // and initialized our decoder. Determine granulepos of buffered packets.
+    ReconstructVorbisGranulepos();
+    for (uint32_t i = 0; i < mUnstamped.Length(); ++i) {
+      ogg_packet* packet = mUnstamped[i];
+      AssertHasRecordedPacketSamples(packet);
+      NS_ASSERTION(!IsHeader(packet), "Don't try to recover header packet gp");
+      NS_ASSERTION(packet->granulepos != -1, "Packet must have gp by now");
+      mPackets.Append(packet);
+    }
+    mUnstamped.Clear();
+  }
+  return NS_OK;
+}
+
+nsresult
+VorbisState::ReconstructVorbisGranulepos()
+{
+  // The number of samples in a Vorbis packet is:
+  // window_blocksize(previous_packet)/4+window_blocksize(current_packet)/4
+  // See: http://xiph.org/vorbis/doc/Vorbis_I_spec.html#x1-230001.3.2
+  // So we maintain mPrevVorbisBlockSize, the block size of the last packet
+  // encountered. We also maintain mGranulepos, which is the granulepos of
+  // the last encountered packet. This enables us to give granulepos to
+  // packets when the last packet in mUnstamped doesn't have a granulepos
+  // (for example if the stream was truncated).
+  //
+  // We validate our prediction of the number of samples decoded when
+  // VALIDATE_VORBIS_SAMPLE_CALCULATION is defined by recording the predicted
+  // number of samples, and verifing we extract that many when decoding
+  // each packet.
+
+  NS_ASSERTION(mUnstamped.Length() > 0, "Length must be > 0");
+  ogg_packet* last = mUnstamped.LastElement();
+  NS_ASSERTION(last->e_o_s || last->granulepos >= 0,
+    "Must know last granulepos!");
+  if (mUnstamped.Length() == 1) {
+    ogg_packet* packet = mUnstamped[0];
+    long blockSize = vorbis_packet_blocksize(&mInfo, packet);
+    if (blockSize < 0) {
+      // On failure vorbis_packet_blocksize returns < 0. If we've got
+      // a bad packet, we just assume that decode will have to skip this
+      // packet, i.e. assume 0 samples are decodable from this packet.
+      blockSize = 0;
+      mPrevVorbisBlockSize = 0;
+    }
+    long samples = mPrevVorbisBlockSize / 4 + blockSize / 4;
+    mPrevVorbisBlockSize = blockSize;
+    if (packet->granulepos == -1) {
+      packet->granulepos = mGranulepos + samples;
+    }
+
+    // Account for a partial last frame
+    if (packet->e_o_s && packet->granulepos >= mGranulepos) {
+       samples = packet->granulepos - mGranulepos;
+    }
+
+    mGranulepos = packet->granulepos;
+    RecordVorbisPacketSamples(packet, samples);
+    return NS_OK;
+  }
+
+  bool unknownGranulepos = last->granulepos == -1;
+  int totalSamples = 0;
+  for (int32_t i = mUnstamped.Length() - 1; i > 0; i--) {
+    ogg_packet* packet = mUnstamped[i];
+    ogg_packet* prev = mUnstamped[i-1];
+    ogg_int64_t granulepos = packet->granulepos;
+    NS_ASSERTION(granulepos != -1, "Must know granulepos!");
+    long prevBlockSize = vorbis_packet_blocksize(&mInfo, prev);
+    long blockSize = vorbis_packet_blocksize(&mInfo, packet);
+
+    if (blockSize < 0 || prevBlockSize < 0) {
+      // On failure vorbis_packet_blocksize returns < 0. If we've got
+      // a bad packet, we just assume that decode will have to skip this
+      // packet, i.e. assume 0 samples are decodable from this packet.
+      blockSize = 0;
+      prevBlockSize = 0;
+    }
+
+    long samples = prevBlockSize / 4 + blockSize / 4;
+    totalSamples += samples;
+    prev->granulepos = granulepos - samples;
+    RecordVorbisPacketSamples(packet, samples);
+  }
+
+  if (unknownGranulepos) {
+    for (uint32_t i = 0; i < mUnstamped.Length(); i++) {
+      ogg_packet* packet = mUnstamped[i];
+      packet->granulepos += mGranulepos + totalSamples + 1;
+    }
+  }
+
+  ogg_packet* first = mUnstamped[0];
+  long blockSize = vorbis_packet_blocksize(&mInfo, first);
+  if (blockSize < 0) {
+    mPrevVorbisBlockSize = 0;
+    blockSize = 0;
+  }
+
+  long samples = (mPrevVorbisBlockSize == 0) ? 0 :
+                  mPrevVorbisBlockSize / 4 + blockSize / 4;
+  int64_t start = first->granulepos - samples;
+  RecordVorbisPacketSamples(first, samples);
+
+  if (last->e_o_s && start < mGranulepos) {
+    // We've calculated that there are more samples in this page than its
+    // granulepos claims, and it's the last page in the stream. This is legal,
+    // and we will need to prune the trailing samples when we come to decode it.
+    // We must correct the timestamps so that they follow the last Vorbis page's
+    // samples.
+    int64_t pruned = mGranulepos - start;
+    for (uint32_t i = 0; i < mUnstamped.Length() - 1; i++) {
+      mUnstamped[i]->granulepos += pruned;
+    }
+#ifdef VALIDATE_VORBIS_SAMPLE_CALCULATION
+    mVorbisPacketSamples[last] -= pruned;
+#endif
+  }
+
+  mPrevVorbisBlockSize = vorbis_packet_blocksize(&mInfo, last);
+  mPrevVorbisBlockSize = std::max(static_cast<long>(0), mPrevVorbisBlockSize);
+  mGranulepos = last->granulepos;
+
+  return NS_OK;
+}
+
+OpusState::OpusState(ogg_page* aBosPage)
+  : OggCodecState(aBosPage, true)
+  , mParser(nullptr)
+  , mDecoder(nullptr)
+  , mSkip(0)
+  , mPrevPacketGranulepos(0)
+  , mPrevPageGranulepos(0)
+{
+  MOZ_COUNT_CTOR(OpusState);
+}
+
+OpusState::~OpusState()
+{
+  MOZ_COUNT_DTOR(OpusState);
+  Reset();
+
+  if (mDecoder) {
+    opus_multistream_decoder_destroy(mDecoder);
+    mDecoder = nullptr;
+  }
+}
+
+nsresult
+OpusState::Reset()
+{
+  return Reset(false);
+}
+
+nsresult
+OpusState::Reset(bool aStart)
+{
+  nsresult res = NS_OK;
+
+  if (mActive && mDecoder) {
+    // Reset the decoder.
+    opus_multistream_decoder_ctl(mDecoder, OPUS_RESET_STATE);
+    // Let the seek logic handle pre-roll if we're not seeking to the start.
+    mSkip = aStart ? mParser->mPreSkip : 0;
+    // This lets us distinguish the first page being the last page vs. just
+    // not having processed the previous page when we encounter the last page.
+    mPrevPageGranulepos = aStart ? 0 : -1;
+    mPrevPacketGranulepos = aStart ? 0 : -1;
+  }
+
+  // Clear queued data.
+  if (NS_FAILED(OggCodecState::Reset())) {
+    return NS_ERROR_FAILURE;
+  }
+
+  LOG(LogLevel::Debug, ("Opus decoder reset, to skip %d", mSkip));
+
+  return res;
+}
+
+bool
+OpusState::Init(void)
+{
+  if (!mActive) {
+    return false;
+  }
+
+  int error;
+
+  NS_ASSERTION(mDecoder == nullptr, "leaking OpusDecoder");
+
+  mDecoder = opus_multistream_decoder_create(mParser->mRate,
+                                             mParser->mChannels,
+                                             mParser->mStreams,
+                                             mParser->mCoupledStreams,
+                                             mParser->mMappingTable,
+                                             &error);
+
+  mSkip = mParser->mPreSkip;
+
+  LOG(LogLevel::Debug, ("Opus decoder init, to skip %d", mSkip));
+
+  return error == OPUS_OK;
+}
+
+bool
+OpusState::DecodeHeader(ogg_packet* aPacket)
+{
+  nsAutoRef<ogg_packet> autoRelease(aPacket);
+  switch(mPacketCount++) {
+    // Parse the id header.
+    case 0:
+      mParser = new OpusParser;
+      if (!mParser->DecodeHeader(aPacket->packet, aPacket->bytes)) {
+        return false;
+      }
+      mRate = mParser->mRate;
+      mChannels = mParser->mChannels;
+      mPreSkip = mParser->mPreSkip;
+#ifdef MOZ_SAMPLE_TYPE_FLOAT32
+      mGain = mParser->mGain;
+#else
+      mGain_Q16 = mParser->mGain_Q16;
+#endif
+      break;
+
+    // Parse the metadata header.
+    case 1:
+      if (!mParser->DecodeTags(aPacket->packet, aPacket->bytes)) {
+        return false;
+      }
+      break;
+
+    // We made it to the first data packet (which includes reconstructing
+    // timestamps for it in PageIn). Success!
+    default:
+      mDoneReadingHeaders = true;
+      // Put it back on the queue so we can decode it.
+      mPackets.PushFront(autoRelease.disown());
+      break;
+  }
+  return true;
+}
+
+/* Construct and return a tags hashmap from our internal array */
+MetadataTags*
+OpusState::GetTags()
+{
+  MetadataTags* tags;
+
+  tags = new MetadataTags;
+  for (uint32_t i = 0; i < mParser->mTags.Length(); i++) {
+    AddVorbisComment(tags, mParser->mTags[i].Data(), mParser->mTags[i].Length());
+  }
+
+  return tags;
+}
+
+/* Return the timestamp (in microseconds) equivalent to a granulepos. */
+int64_t
+OpusState::Time(int64_t aGranulepos)
+{
+  if (!mActive) {
+    return -1;
+  }
+
+  return Time(mParser->mPreSkip, aGranulepos);
+}
+
+int64_t
+OpusState::Time(int aPreSkip, int64_t aGranulepos)
+{
+  if (aGranulepos < 0) {
+    return -1;
+  }
+
+  // Ogg Opus always runs at a granule rate of 48 kHz.
+  CheckedInt64 t = SaferMultDiv(aGranulepos - aPreSkip, USECS_PER_S, 48000);
+  return t.isValid() ? t.value() : -1;
+}
+
+bool
+OpusState::IsHeader(ogg_packet* aPacket)
+{
+  return aPacket->bytes >= 16 &&
+         (!memcmp(aPacket->packet, "OpusHead", 8) ||
+          !memcmp(aPacket->packet, "OpusTags", 8));
+}
+
+nsresult
+OpusState::PageIn(ogg_page* aPage)
+{
+  if (!mActive) {
+    return NS_OK;
+  }
+  NS_ASSERTION(static_cast<uint32_t>(ogg_page_serialno(aPage)) == mSerial,
+               "Page must be for this stream!");
+  if (ogg_stream_pagein(&mState, aPage) == -1)
+    return NS_ERROR_FAILURE;
+
+  bool haveGranulepos;
+  nsresult rv = PacketOutUntilGranulepos(haveGranulepos);
+  if (NS_FAILED(rv) || !haveGranulepos || mPacketCount < 2) {
+    return rv;
+  }
+  if (!ReconstructOpusGranulepos()) {
+    return NS_ERROR_FAILURE;
+  }
+  for (uint32_t i = 0; i < mUnstamped.Length(); i++) {
+    ogg_packet* packet = mUnstamped[i];
+    NS_ASSERTION(!IsHeader(packet), "Don't try to play a header packet");
+    NS_ASSERTION(packet->granulepos != -1, "Packet should have a granulepos");
+    mPackets.Append(packet);
+  }
+  mUnstamped.Clear();
+  return NS_OK;
+}
+
+// Helper method to return the change in granule position due to an Opus packet
+// (as distinct from the number of samples in the packet, which depends on the
+// decoder rate). It should work with a multistream Opus file, and continue to
+// work should we ever allow the decoder to decode at a rate other than 48 kHz.
+// It even works before we've created the actual Opus decoder.
+static int
+GetOpusDeltaGP(ogg_packet* packet)
+{
+  int nframes;
+  nframes = opus_packet_get_nb_frames(packet->packet, packet->bytes);
+  if (nframes > 0) {
+    return nframes*opus_packet_get_samples_per_frame(packet->packet, 48000);
+  }
+  NS_WARNING("Invalid Opus packet.");
+  return nframes;
+}
+
+int64_t
+OpusState::PacketDuration(ogg_packet* aPacket)
+{
+  CheckedInt64 t = SaferMultDiv(GetOpusDeltaGP(aPacket), USECS_PER_S, 48000);
+  return t.isValid() ? t.value() : -1;
+}
+
+bool
+OpusState::ReconstructOpusGranulepos(void)
+{
+  NS_ASSERTION(mUnstamped.Length() > 0, "Must have unstamped packets");
+  ogg_packet* last = mUnstamped.LastElement();
+  NS_ASSERTION(last->e_o_s || last->granulepos > 0,
+      "Must know last granulepos!");
+  int64_t gp;
+  // If this is the last page, and we've seen at least one previous page (or
+  // this is the first page)...
+  if (last->e_o_s) {
+    if (mPrevPageGranulepos != -1) {
+      // If this file only has one page and the final granule position is
+      // smaller than the pre-skip amount, we MUST reject the stream.
+      if (!mDoneReadingHeaders && last->granulepos < mPreSkip)
+        return false;
+      int64_t last_gp = last->granulepos;
+      gp = mPrevPageGranulepos;
+      // Loop through the packets forwards, adding the current packet's
+      // duration to the previous granulepos to get the value for the
+      // current packet.
+      for (uint32_t i = 0; i < mUnstamped.Length() - 1; ++i) {
+        ogg_packet* packet = mUnstamped[i];
+        int offset = GetOpusDeltaGP(packet);
+        // Check for error (negative offset) and overflow.
+        if (offset >= 0 && gp <= INT64_MAX - offset) {
+          gp += offset;
+          if (gp >= last_gp) {
+            NS_WARNING("Opus end trimming removed more than a full packet.");
+            // We were asked to remove a full packet's worth of data or more.
+            // Encoders SHOULD NOT produce streams like this, but we'll handle
+            // it for them anyway.
+            gp = last_gp;
+            for (uint32_t j = i+1; j < mUnstamped.Length(); ++j) {
+              OggCodecState::ReleasePacket(mUnstamped[j]);
+            }
+            mUnstamped.RemoveElementsAt(i+1, mUnstamped.Length() - (i+1));
+            last = packet;
+            last->e_o_s = 1;
+          }
+        }
+        packet->granulepos = gp;
+      }
+      mPrevPageGranulepos = last_gp;
+      return true;
+    } else {
+      NS_WARNING("No previous granule position to use for Opus end trimming.");
+      // If we don't have a previous granule position, fall through.
+      // We simply won't trim any samples from the end.
+      // TODO: Are we guaranteed to have seen a previous page if there is one?
+    }
+  }
+
+  gp = last->granulepos;
+  // Loop through the packets backwards, subtracting the next
+  // packet's duration from its granulepos to get the value
+  // for the current packet.
+  for (uint32_t i = mUnstamped.Length() - 1; i > 0; i--) {
+    int offset = GetOpusDeltaGP(mUnstamped[i]);
+    // Check for error (negative offset) and overflow.
+    if (offset >= 0) {
+      if (offset <= gp) {
+        gp -= offset;
+      } else {
+        // If the granule position of the first data page is smaller than the
+        // number of decodable audio samples on that page, then we MUST reject
+        // the stream.
+        if (!mDoneReadingHeaders)
+          return false;
+        // It's too late to reject the stream.
+        // If we get here, this almost certainly means the file has screwed-up
+        // timestamps somewhere after the first page.
+        NS_WARNING("Clamping negative Opus granulepos to zero.");
+        gp = 0;
+      }
+    }
+    mUnstamped[i - 1]->granulepos = gp;
+  }
+
+  // Check to make sure the first granule position is at least as large as the
+  // total number of samples decodable from the first page with completed
+  // packets. This requires looking at the duration of the first packet, too.
+  // We MUST reject such streams.
+  if (!mDoneReadingHeaders && GetOpusDeltaGP(mUnstamped[0]) > gp) {
+    return false;
+  }
+  mPrevPageGranulepos = last->granulepos;
+  return true;
+}
+
+already_AddRefed<MediaRawData>
+OpusState::PacketOutAsMediaRawData()
+{
+  ogg_packet* packet = PacketPeek();
+  uint32_t frames = 0;
+  const int64_t endFrame = packet->granulepos;
+
+  if (!packet) {
+    return nullptr;
+  }
+  if (packet->e_o_s) {
+    frames = GetOpusDeltaGP(packet);
+  }
+
+  RefPtr<MediaRawData> data = OggCodecState::PacketOutAsMediaRawData();
+  if (!data) {
+    return nullptr;
+  }
+
+  if (data->mEOS && mPrevPacketGranulepos != -1) {
+    // If this is the last packet, perform end trimming.
+    int64_t startFrame = mPrevPacketGranulepos;
+    frames -= std::max<int64_t>(
+      0, std::min(endFrame - startFrame, static_cast<int64_t>(frames)));
+    data->mDiscardPadding = frames;
+  }
+
+  // Save this packet's granule position in case we need to perform end
+  // trimming on the next packet.
+  mPrevPacketGranulepos = endFrame;
+
+  return data.forget();
+}
+
+FlacState::FlacState(ogg_page* aBosPage)
+  : OggCodecState(aBosPage, true)
+{
+}
+
+bool
+FlacState::DecodeHeader(ogg_packet* aPacket)
+{
+  nsAutoRef<ogg_packet> autoRelease(aPacket);
+
+  if (!mParser.DecodeHeaderBlock(aPacket->packet, aPacket->bytes)) {
+    return false;
+  }
+  if (mParser.HasFullMetadata()) {
+    mDoneReadingHeaders = true;
+  }
+  return true;
+}
+
+int64_t
+FlacState::Time(int64_t granulepos)
+{
+  if (!mParser.mInfo.IsValid()) {
+    return -1;
+  }
+  CheckedInt64 t =
+      SaferMultDiv(granulepos, USECS_PER_S, mParser.mInfo.mRate);
+  if (!t.isValid()) {
+    return -1;
+  }
+  return t.value();
+}
+
+int64_t
+FlacState::PacketDuration(ogg_packet* aPacket)
+{
+  return mParser.BlockDuration(aPacket->packet, aPacket->bytes);
+}
+
+bool
+FlacState::IsHeader(ogg_packet* aPacket)
+{
+  return mParser.IsHeaderBlock(aPacket->packet, aPacket->bytes);
+}
+
+nsresult
+FlacState::PageIn(ogg_page* aPage)
+{
+  if (!mActive) {
+    return NS_OK;
+  }
+  NS_ASSERTION(static_cast<uint32_t>(ogg_page_serialno(aPage)) == mSerial,
+               "Page must be for this stream!");
+  if (ogg_stream_pagein(&mState, aPage) == -1)
+    return NS_ERROR_FAILURE;
+  bool foundGp;
+  nsresult res = PacketOutUntilGranulepos(foundGp);
+  if (NS_FAILED(res)) {
+    return res;
+  }
+  if (foundGp && mDoneReadingHeaders) {
+    // We've found a packet with a granulepos, and we've loaded our metadata
+    // and initialized our decoder. Determine granulepos of buffered packets.
+    ReconstructFlacGranulepos();
+    for (uint32_t i = 0; i < mUnstamped.Length(); ++i) {
+      ogg_packet* packet = mUnstamped[i];
+      NS_ASSERTION(!IsHeader(packet), "Don't try to recover header packet gp");
+      NS_ASSERTION(packet->granulepos != -1, "Packet must have gp by now");
+      mPackets.Append(packet);
+    }
+    mUnstamped.Clear();
+  }
+  return NS_OK;
+}
+
+// Return a hash table with tag metadata.
+MetadataTags*
+FlacState::GetTags()
+{
+  return mParser.GetTags();
+}
+
+const AudioInfo&
+FlacState::Info()
+{
+  return mParser.mInfo;
+}
+
+bool
+FlacState::ReconstructFlacGranulepos(void)
+{
+  NS_ASSERTION(mUnstamped.Length() > 0, "Must have unstamped packets");
+  ogg_packet* last = mUnstamped.LastElement();
+  NS_ASSERTION(last->e_o_s || last->granulepos > 0,
+      "Must know last granulepos!");
+  int64_t gp;
+
+  gp = last->granulepos;
+  // Loop through the packets backwards, subtracting the next
+  // packet's duration from its granulepos to get the value
+  // for the current packet.
+  for (uint32_t i = mUnstamped.Length() - 1; i > 0; i--) {
+    int offset =
+        mParser.BlockDuration(mUnstamped[i]->packet, mUnstamped[i]->bytes);
+    // Check for error (negative offset) and overflow.
+    if (offset >= 0) {
+      if (offset <= gp) {
+        gp -= offset;
+      } else {
+        // If the granule position of the first data page is smaller than the
+        // number of decodable audio samples on that page, then we MUST reject
+        // the stream.
+        if (!mDoneReadingHeaders) {
+          return false;
+        }
+        // It's too late to reject the stream.
+        // If we get here, this almost certainly means the file has screwed-up
+        // timestamps somewhere after the first page.
+        NS_WARNING("Clamping negative granulepos to zero.");
+        gp = 0;
+      }
+    }
+    mUnstamped[i - 1]->granulepos = gp;
+  }
+
+  return true;
+}
+
+SkeletonState::SkeletonState(ogg_page* aBosPage)
+  : OggCodecState(aBosPage, true)
+  , mVersion(0)
+  , mPresentationTime(0)
+  , mLength(0)
+{
+  MOZ_COUNT_CTOR(SkeletonState);
+}
+
+SkeletonState::~SkeletonState()
+{
+  MOZ_COUNT_DTOR(SkeletonState);
+}
+
+// Support for Ogg Skeleton 4.0, as per specification at:
+// http://wiki.xiph.org/Ogg_Skeleton_4
+
+// Minimum length in bytes of a Skeleton header packet.
+static const long SKELETON_MIN_HEADER_LEN = 28;
+static const long SKELETON_4_0_MIN_HEADER_LEN = 80;
+
+// Minimum length in bytes of a Skeleton 4.0 index packet.
+static const long SKELETON_4_0_MIN_INDEX_LEN = 42;
+
+// Minimum length in bytes of a Skeleton 3.0/4.0 Fisbone packet.
+static const long SKELETON_MIN_FISBONE_LEN = 52;
+
+// Minimum possible size of a compressed index keypoint.
+static const size_t MIN_KEY_POINT_SIZE = 2;
+
+// Byte offset of the major and minor version numbers in the
+// Ogg Skeleton 4.0 header packet.
+static const size_t SKELETON_VERSION_MAJOR_OFFSET = 8;
+static const size_t SKELETON_VERSION_MINOR_OFFSET = 10;
+
+// Byte-offsets of the presentation time numerator and denominator
+static const size_t SKELETON_PRESENTATION_TIME_NUMERATOR_OFFSET = 12;
+static const size_t SKELETON_PRESENTATION_TIME_DENOMINATOR_OFFSET = 20;
+
+// Byte-offsets of the length of file field in the Skeleton 4.0 header packet.
+static const size_t SKELETON_FILE_LENGTH_OFFSET = 64;
+
+// Byte-offsets of the fields in the Skeleton index packet.
+static const size_t INDEX_SERIALNO_OFFSET = 6;
+static const size_t INDEX_NUM_KEYPOINTS_OFFSET = 10;
+static const size_t INDEX_TIME_DENOM_OFFSET = 18;
+static const size_t INDEX_FIRST_NUMER_OFFSET = 26;
+static const size_t INDEX_LAST_NUMER_OFFSET = 34;
+static const size_t INDEX_KEYPOINT_OFFSET = 42;
+
+// Byte-offsets of the fields in the Skeleton Fisbone packet.
+static const size_t FISBONE_MSG_FIELDS_OFFSET = 8;
+static const size_t FISBONE_SERIALNO_OFFSET = 12;
+
+static bool
+IsSkeletonBOS(ogg_packet* aPacket)
+{
+  static_assert(SKELETON_MIN_HEADER_LEN >= 8,
+                "Minimum length of skeleton BOS header incorrect");
+  return aPacket->bytes >= SKELETON_MIN_HEADER_LEN &&
+         memcmp(reinterpret_cast<char*>(aPacket->packet), "fishead", 8) == 0;
+}
+
+static bool
+IsSkeletonIndex(ogg_packet* aPacket)
+{
+  static_assert(SKELETON_4_0_MIN_INDEX_LEN >= 5,
+                "Minimum length of skeleton index header incorrect");
+  return aPacket->bytes >= SKELETON_4_0_MIN_INDEX_LEN &&
+         memcmp(reinterpret_cast<char*>(aPacket->packet), "index", 5) == 0;
+}
+
+static bool
+IsSkeletonFisbone(ogg_packet* aPacket)
+{
+  static_assert(SKELETON_MIN_FISBONE_LEN >= 8,
+                "Minimum length of skeleton fisbone header incorrect");
+  return aPacket->bytes >= SKELETON_MIN_FISBONE_LEN &&
+         memcmp(reinterpret_cast<char*>(aPacket->packet), "fisbone", 8) == 0;
+}
+
+// Reads a variable length encoded integer at p. Will not read
+// past aLimit. Returns pointer to character after end of integer.
+static const unsigned char*
+ReadVariableLengthInt(const unsigned char* p,
+                      const unsigned char* aLimit,
+                      int64_t& n)
+{
+  int shift = 0;
+  int64_t byte = 0;
+  n = 0;
+  while (p < aLimit &&
+         (byte & 0x80) != 0x80 &&
+         shift < 57)
+  {
+    byte = static_cast<int64_t>(*p);
+    n |= ((byte & 0x7f) << shift);
+    shift += 7;
+    p++;
+  }
+  return p;
+}
+
+bool
+SkeletonState::DecodeIndex(ogg_packet* aPacket)
+{
+  NS_ASSERTION(aPacket->bytes >= SKELETON_4_0_MIN_INDEX_LEN,
+               "Index must be at least minimum size");
+  if (!mActive) {
+    return false;
+  }
+
+  uint32_t serialno = LittleEndian::readUint32(aPacket->packet + INDEX_SERIALNO_OFFSET);
+  int64_t numKeyPoints = LittleEndian::readInt64(aPacket->packet + INDEX_NUM_KEYPOINTS_OFFSET);
+
+  int64_t endTime = 0, startTime = 0;
+  const unsigned char* p = aPacket->packet;
+
+  int64_t timeDenom = LittleEndian::readInt64(aPacket->packet + INDEX_TIME_DENOM_OFFSET);
+  if (timeDenom == 0) {
+    LOG(LogLevel::Debug, ("Ogg Skeleton Index packet for stream %u has 0 "
+                       "timestamp denominator.", serialno));
+    return (mActive = false);
+  }
+
+  // Extract the start time.
+  int64_t timeRawInt = LittleEndian::readInt64(p + INDEX_FIRST_NUMER_OFFSET);
+  CheckedInt64 t = SaferMultDiv(timeRawInt, USECS_PER_S, timeDenom);
+  if (!t.isValid()) {
+    return (mActive = false);
+  } else {
+    startTime = t.value();
+  }
+
+  // Extract the end time.
+  timeRawInt = LittleEndian::readInt64(p + INDEX_LAST_NUMER_OFFSET);
+  t = SaferMultDiv(timeRawInt, USECS_PER_S, timeDenom);
+  if (!t.isValid()) {
+    return (mActive = false);
+  } else {
+    endTime = t.value();
+  }
+
+  // Check the numKeyPoints value read, ensure we're not going to run out of
+  // memory while trying to decode the index packet.
+  CheckedInt64 minPacketSize =
+    (CheckedInt64(numKeyPoints) * MIN_KEY_POINT_SIZE) + INDEX_KEYPOINT_OFFSET;
+  if (!minPacketSize.isValid())
+  {
+    return (mActive = false);
+  }
+
+  int64_t sizeofIndex = aPacket->bytes - INDEX_KEYPOINT_OFFSET;
+  int64_t maxNumKeyPoints = sizeofIndex / MIN_KEY_POINT_SIZE;
+  if (aPacket->bytes < minPacketSize.value() ||
+      numKeyPoints > maxNumKeyPoints ||
+      numKeyPoints < 0) {
+    // Packet size is less than the theoretical minimum size, or the packet is
+    // claiming to store more keypoints than it's capable of storing. This means
+    // that the numKeyPoints field is too large or small for the packet to
+    // possibly contain as many packets as it claims to, so the numKeyPoints
+    // field is possibly malicious. Don't try decoding this index, we may run
+    // out of memory.
+    LOG(LogLevel::Debug, ("Possibly malicious number of key points reported "
+                       "(%lld) in index packet for stream %u.",
+                       numKeyPoints,
+                       serialno));
+    return (mActive = false);
+  }
+
+  nsAutoPtr<nsKeyFrameIndex> keyPoints(new nsKeyFrameIndex(startTime, endTime));
+
+  p = aPacket->packet + INDEX_KEYPOINT_OFFSET;
+  const unsigned char* limit = aPacket->packet + aPacket->bytes;
+  int64_t numKeyPointsRead = 0;
+  CheckedInt64 offset = 0;
+  CheckedInt64 time = 0;
+  while (p < limit && numKeyPointsRead < numKeyPoints) {
+    int64_t delta = 0;
+    p = ReadVariableLengthInt(p, limit, delta);
+    offset += delta;
+    if (p == limit ||
+        !offset.isValid() ||
+        offset.value() > mLength ||
+        offset.value() < 0) {
+      return (mActive = false);
+    }
+    p = ReadVariableLengthInt(p, limit, delta);
+    time += delta;
+    if (!time.isValid() ||
+        time.value() > endTime ||
+        time.value() < startTime) {
+      return (mActive = false);
+    }
+    CheckedInt64 timeUsecs = SaferMultDiv(time.value(), USECS_PER_S, timeDenom);
+    if (!timeUsecs.isValid()) {
+      return (mActive = false);
+    }
+    keyPoints->Add(offset.value(), timeUsecs.value());
+    numKeyPointsRead++;
+  }
+
+  int32_t keyPointsRead = keyPoints->Length();
+  if (keyPointsRead > 0) {
+    mIndex.Put(serialno, keyPoints.forget());
+  }
+
+  LOG(LogLevel::Debug, ("Loaded %d keypoints for Skeleton on stream %u",
+                     keyPointsRead, serialno));
+  return true;
+}
+
+nsresult
+SkeletonState::IndexedSeekTargetForTrack(uint32_t aSerialno,
+                                         int64_t aTarget,
+                                         nsKeyPoint& aResult)
+{
+  nsKeyFrameIndex* index = nullptr;
+  mIndex.Get(aSerialno, &index);
+
+  if (!index || index->Length() == 0 ||
+      aTarget < index->mStartTime || aTarget > index->mEndTime) {
+    return NS_ERROR_FAILURE;
+  }
+
+  // Binary search to find the last key point with time less than target.
+  int start = 0;
+  int end = index->Length() - 1;
+  while (end > start) {
+    int mid = start + ((end - start + 1) >> 1);
+    if (index->Get(mid).mTime == aTarget) {
+       start = mid;
+       break;
+    } else if (index->Get(mid).mTime < aTarget) {
+      start = mid;
+    } else {
+      end = mid - 1;
+    }
+  }
+
+  aResult = index->Get(start);
+  NS_ASSERTION(aResult.mTime <= aTarget, "Result should have time <= target");
+  return NS_OK;
+}
+
+nsresult
+SkeletonState::IndexedSeekTarget(int64_t aTarget,
+                                 nsTArray<uint32_t>& aTracks,
+                                 nsSeekTarget& aResult)
+{
+  if (!mActive || mVersion < SKELETON_VERSION(4,0)) {
+    return NS_ERROR_FAILURE;
+  }
+  // Loop over all requested tracks' indexes, and get the keypoint for that
+  // seek target. Record the keypoint with the lowest offset, this will be
+  // our seek result. User must seek to the one with lowest offset to ensure we
+  // pass "keyframes" on all tracks when we decode forwards to the seek target.
+  nsSeekTarget r;
+  for (uint32_t i=0; i<aTracks.Length(); i++) {
+    nsKeyPoint k;
+    if (NS_SUCCEEDED(IndexedSeekTargetForTrack(aTracks[i], aTarget, k)) &&
+        k.mOffset < r.mKeyPoint.mOffset) {
+      r.mKeyPoint = k;
+      r.mSerial = aTracks[i];
+    }
+  }
+  if (r.IsNull()) {
+    return NS_ERROR_FAILURE;
+  }
+  LOG(LogLevel::Debug, ("Indexed seek target for time %lld is offset %lld",
+                     aTarget, r.mKeyPoint.mOffset));
+  aResult = r;
+  return NS_OK;
+}
+
+nsresult
+SkeletonState::GetDuration(const nsTArray<uint32_t>& aTracks,
+                           int64_t& aDuration)
+{
+  if (!mActive ||
+      mVersion < SKELETON_VERSION(4,0) ||
+      !HasIndex() ||
+      aTracks.Length() == 0) {
+    return NS_ERROR_FAILURE;
+  }
+  int64_t endTime = INT64_MIN;
+  int64_t startTime = INT64_MAX;
+  for (uint32_t i=0; i<aTracks.Length(); i++) {
+    nsKeyFrameIndex* index = nullptr;
+    mIndex.Get(aTracks[i], &index);
+    if (!index) {
+      // Can't get the timestamps for one of the required tracks, fail.
+      return NS_ERROR_FAILURE;
+    }
+    if (index->mEndTime > endTime) {
+      endTime = index->mEndTime;
+    }
+    if (index->mStartTime < startTime) {
+      startTime = index->mStartTime;
+    }
+  }
+  NS_ASSERTION(endTime > startTime, "Duration must be positive");
+  CheckedInt64 duration = CheckedInt64(endTime) - startTime;
+  aDuration = duration.isValid() ? duration.value() : 0;
+  return duration.isValid() ? NS_OK : NS_ERROR_FAILURE;
+}
+
+bool
+SkeletonState::DecodeFisbone(ogg_packet* aPacket)
+{
+  if (aPacket->bytes < static_cast<long>(FISBONE_MSG_FIELDS_OFFSET + 4)) {
+    return false;
+  }
+  uint32_t offsetMsgField =
+    LittleEndian::readUint32(aPacket->packet + FISBONE_MSG_FIELDS_OFFSET);
+
+  if (aPacket->bytes < static_cast<long>(FISBONE_SERIALNO_OFFSET + 4)) {
+      return false;
+  }
+  uint32_t serialno =
+    LittleEndian::readUint32(aPacket->packet + FISBONE_SERIALNO_OFFSET);
+
+  CheckedUint32 checked_fields_pos =
+    CheckedUint32(FISBONE_MSG_FIELDS_OFFSET) + offsetMsgField;
+  if (!checked_fields_pos.isValid() ||
+      aPacket->bytes < static_cast<int64_t>(checked_fields_pos.value())) {
+    return false;
+  }
+  int64_t msgLength = aPacket->bytes - checked_fields_pos.value();
+  char* msgProbe = (char*)aPacket->packet + checked_fields_pos.value();
+  char* msgHead = msgProbe;
+  nsAutoPtr<MessageField> field(new MessageField());
+
+  const static FieldPatternType kFieldTypeMaps[] = {
+      {"Content-Type:", eContentType},
+      {"Role:", eRole},
+      {"Name:", eName},
+      {"Language:", eLanguage},
+      {"Title:", eTitle},
+      {"Display-hint:", eDisplayHint},
+      {"Altitude:", eAltitude},
+      {"TrackOrder:", eTrackOrder},
+      {"Track dependencies:", eTrackDependencies}
+  };
+
+  bool isContentTypeParsed = false;
+  while (msgLength > 1) {
+    if (*msgProbe == '\r' && *(msgProbe+1) == '\n') {
+      nsAutoCString strMsg(msgHead, msgProbe-msgHead);
+      for (size_t i = 0; i < ArrayLength(kFieldTypeMaps); i++) {
+        if (strMsg.Find(kFieldTypeMaps[i].mPatternToRecognize) != -1) {
+          // The content of message header fields follows [RFC2822], and the
+          // mandatory message field must be encoded in US-ASCII, others
+          // must be be encoded in UTF-8. "Content-Type" must come first
+          // for all of message header fields.
+          // See http://svn.annodex.net/standards/draft-pfeiffer-oggskeleton-current.txt.
+          if (i != 0 && !isContentTypeParsed) {
+            return false;
+          }
+
+          if ((i == 0 && IsASCII(strMsg)) || (i != 0 && IsUTF8(strMsg))) {
+            EMsgHeaderType eHeaderType = kFieldTypeMaps[i].mMsgHeaderType;
+            if (!field->mValuesStore.Contains(eHeaderType)) {
+              uint32_t nameLen = strlen(kFieldTypeMaps[i].mPatternToRecognize);
+              field->mValuesStore.Put(eHeaderType, new nsCString(msgHead+nameLen,
+                                                                 msgProbe-msgHead-nameLen));
+            }
+            isContentTypeParsed = i==0 ? true : isContentTypeParsed;
+          }
+          break;
+        }
+      }
+      msgProbe += 2;
+      msgLength -= 2;
+      msgHead = msgProbe;
+      continue;
+    }
+    msgLength--;
+    msgProbe++;
+  }
+
+  if (!mMsgFieldStore.Contains(serialno)) {
+    mMsgFieldStore.Put(serialno, field.forget());
+  } else {
+    return false;
+  }
+
+  return true;
+}
+
+bool
+SkeletonState::DecodeHeader(ogg_packet* aPacket)
+{
+  nsAutoRef<ogg_packet> autoRelease(aPacket);
+  if (IsSkeletonBOS(aPacket)) {
+    uint16_t verMajor =
+      LittleEndian::readUint16(aPacket->packet + SKELETON_VERSION_MAJOR_OFFSET);
+    uint16_t verMinor =
+      LittleEndian::readUint16(aPacket->packet + SKELETON_VERSION_MINOR_OFFSET);
+
+    // Read the presentation time. We read this before the version check as the
+    // presentation time exists in all versions.
+    int64_t n =
+      LittleEndian::readInt64(aPacket->packet + SKELETON_PRESENTATION_TIME_NUMERATOR_OFFSET);
+    int64_t d =
+      LittleEndian::readInt64(aPacket->packet + SKELETON_PRESENTATION_TIME_DENOMINATOR_OFFSET);
+    mPresentationTime =
+      d == 0 ? 0 : (static_cast<float>(n) / static_cast<float>(d)) * USECS_PER_S;
+
+    mVersion = SKELETON_VERSION(verMajor, verMinor);
+    // We can only care to parse Skeleton version 4.0+.
+    if (mVersion < SKELETON_VERSION(4,0) ||
+        mVersion >= SKELETON_VERSION(5,0) ||
+        aPacket->bytes < SKELETON_4_0_MIN_HEADER_LEN) {
+      return false;
+    }
+
+    // Extract the segment length.
+    mLength =
+      LittleEndian::readInt64(aPacket->packet + SKELETON_FILE_LENGTH_OFFSET);
+
+    LOG(LogLevel::Debug, ("Skeleton segment length: %lld", mLength));
+
+    // Initialize the serialno-to-index map.
+    return true;
+  } else if (IsSkeletonIndex(aPacket) && mVersion >= SKELETON_VERSION(4,0)) {
+    return DecodeIndex(aPacket);
+  } else if (IsSkeletonFisbone(aPacket)) {
+    return DecodeFisbone(aPacket);
+  } else if (aPacket->e_o_s) {
+    mDoneReadingHeaders = true;
+    return true;
+  }
+  return true;
+}
+
+} // namespace mozilla
+
diff --git a/dom/media/ogg/OggCodecState.h b/dom/media/ogg/OggCodecState.h
new file mode 100644
index 0000000000..9c254aa40f
--- /dev/null
+++ b/dom/media/ogg/OggCodecState.h
@@ -0,0 +1,644 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim:set ts=2 sw=2 sts=2 et cindent: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+#if !defined(OggCodecState_h_)
+#define OggCodecState_h_
+
+#include <ogg/ogg.h>
+// For MOZ_SAMPLE_TYPE_*
+#include <nsAutoPtr.h>
+#include <nsAutoRef.h>
+#include <nsDeque.h>
+#include <nsTArray.h>
+#include <nsClassHashtable.h>
+#include "VideoUtils.h"
+#include "FlacFrameParser.h"
+
+#include <theora/theoradec.h>
+#ifdef MOZ_TREMOR
+#include <tremor/ivorbiscodec.h>
+#else
+#include <vorbis/codec.h>
+#endif
+
+// Uncomment the following to validate that we're predicting the number
+// of Vorbis samples in each packet correctly.
+#define VALIDATE_VORBIS_SAMPLE_CALCULATION
+#ifdef  VALIDATE_VORBIS_SAMPLE_CALCULATION
+#include <map>
+#endif
+
+struct OpusMSDecoder;
+
+namespace mozilla {
+
+class OpusParser;
+
+// Deallocates a packet, used in OggPacketQueue below.
+class OggPacketDeallocator : public nsDequeFunctor
+{
+  virtual void* operator() (void* aPacket)
+  {
+    ogg_packet* p = static_cast<ogg_packet*>(aPacket);
+    delete [] p->packet;
+    delete p;
+    return nullptr;
+  }
+};
+
+// A queue of ogg_packets. When we read a page, we extract the page's packets
+// and buffer them in the owning stream's OggCodecState. This is because
+// if we're skipping up to the next keyframe in very large frame sized videos,
+// there may be several megabytes of data between keyframes, and the
+// ogg_stream_state would end up resizing its buffer every time we added a
+// new 4KB page to the bitstream, which kills performance on Windows. This
+// also gives us the option to timestamp packets rather than decoded
+// frames/samples, reducing the amount of frames/samples we must decode to
+// determine start-time at a particular offset, and gives us finer control
+// over memory usage.
+class OggPacketQueue : private nsDeque
+{
+public:
+  OggPacketQueue() : nsDeque(new OggPacketDeallocator()) {}
+  ~OggPacketQueue() { Erase(); }
+  bool IsEmpty() { return nsDeque::GetSize() == 0; }
+  void Append(ogg_packet* aPacket);
+  ogg_packet* PopFront() { return static_cast<ogg_packet*>(nsDeque::PopFront()); }
+  ogg_packet* PeekFront() { return static_cast<ogg_packet*>(nsDeque::PeekFront()); }
+  ogg_packet* Pop() { return static_cast<ogg_packet*>(nsDeque::Pop()); }
+  void PushFront(ogg_packet* aPacket) { nsDeque::PushFront(aPacket); }
+  void Erase() { nsDeque::Erase(); }
+};
+
+// Encapsulates the data required for decoding an ogg bitstream and for
+// converting granulepos to timestamps.
+class OggCodecState
+{
+public:
+  typedef mozilla::MetadataTags MetadataTags;
+  // Ogg types we know about
+  enum CodecType
+  {
+    TYPE_VORBIS=0,
+    TYPE_THEORA,
+    TYPE_OPUS,
+    TYPE_SKELETON,
+    TYPE_FLAC,
+    TYPE_UNKNOWN
+  };
+
+  virtual ~OggCodecState();
+
+  // Factory for creating nsCodecStates. Use instead of constructor.
+  // aPage should be a beginning-of-stream page.
+  static OggCodecState* Create(ogg_page* aPage);
+
+  virtual CodecType GetType() { return TYPE_UNKNOWN; }
+
+  // Reads a header packet. Returns false if an error was encountered
+  // while reading header packets. Callers should check DoneReadingHeaders()
+  // to determine if the last header has been read.
+  // This function takes ownership of the packet and is responsible for
+  // releasing it or queuing it for later processing.
+  virtual bool DecodeHeader(ogg_packet* aPacket)
+  {
+    return (mDoneReadingHeaders = true);
+  }
+
+  // Build a hash table with tag metadata parsed from the stream.
+  virtual MetadataTags* GetTags()
+  {
+    return nullptr;
+  }
+
+  // Returns the end time that a granulepos represents.
+  virtual int64_t Time(int64_t granulepos) { return -1; }
+
+  // Returns the start time that a granulepos represents.
+  virtual int64_t StartTime(int64_t granulepos) { return -1; }
+
+  // Returns the duration of the given packet, if it can be determined.
+  virtual int64_t PacketDuration(ogg_packet* aPacket) { return -1; }
+
+  // Returns the start time of the given packet, if it can be determined.
+  virtual int64_t PacketStartTime(ogg_packet* aPacket)
+  {
+    if (aPacket->granulepos < 0) {
+      return -1;
+    }
+    int64_t endTime = Time(aPacket->granulepos);
+    int64_t duration = PacketDuration(aPacket);
+    if (duration > endTime) {
+      // Audio preskip may eat a whole packet or more.
+      return 0;
+    } else {
+      return endTime - duration;
+    }
+  }
+
+  // Initializes the codec state.
+  virtual bool Init() { return true; }
+
+  // Returns true when this bitstream has finished reading all its
+  // header packets.
+  bool DoneReadingHeaders() { return mDoneReadingHeaders; }
+
+  // Deactivates the bitstream. Only the primary video and audio bitstreams
+  // should be active.
+  void Deactivate()
+  {
+    mActive = false;
+    mDoneReadingHeaders = true;
+    Reset();
+  }
+
+  // Resets decoding state.
+  virtual nsresult Reset();
+
+  // Returns true if the OggCodecState thinks this packet is a header
+  // packet. Note this does not verify the validity of the header packet,
+  // it just guarantees that the packet is marked as a header packet (i.e.
+  // it is definintely not a data packet). Do not use this to identify
+  // streams, use it to filter header packets from data packets while
+  // decoding.
+  virtual bool IsHeader(ogg_packet* aPacket) { return false; }
+
+  // Returns true if the OggCodecState thinks this packet represents a
+  // keyframe, from which decoding can restart safely.
+  virtual bool IsKeyframe(ogg_packet* aPacket) { return true; }
+
+  // Returns true if there is a packet available for dequeueing in the stream.
+  bool IsPacketReady();
+
+  // Returns the next raw packet in the stream, or nullptr if there are no more
+  // packets buffered in the packet queue. More packets can be buffered by
+  // inserting one or more pages into the stream by calling PageIn(). The
+  // caller is responsible for deleting returned packet's using
+  // OggCodecState::ReleasePacket(). The packet will have a valid granulepos.
+  ogg_packet* PacketOut();
+
+  // Returns the next raw packet in the stream, or nullptr if there are no more
+  // packets buffered in the packet queue, without consuming it.
+  // The packet will have a valid granulepos.
+  ogg_packet* PacketPeek();
+
+  // Moves all raw packets from aOther to the front of the current packet queue.
+  void PushFront(OggPacketQueue&& aOther);
+
+  // Releases the memory used by a cloned packet. Every packet returned by
+  // PacketOut() must be free'd using this function.
+  static void ReleasePacket(ogg_packet* aPacket);
+
+  // Returns the next packet in the stream as a MediaRawData, or nullptr
+  // if there are no more packets buffered in the packet queue. More packets
+  // can be buffered by inserting one or more pages into the stream by calling
+  // PageIn(). The packet will have a valid granulepos.
+  virtual already_AddRefed<MediaRawData> PacketOutAsMediaRawData();
+
+  // Extracts all packets from the page, and inserts them into the packet
+  // queue. They can be extracted by calling PacketOut(). Packets from an
+  // inactive stream are not buffered, i.e. this call has no effect for
+  // inactive streams. Multiple pages may need to be inserted before
+  // PacketOut() starts to return packets, as granulepos may need to be
+  // captured.
+  virtual nsresult PageIn(ogg_page* aPage);
+
+  // Number of packets read.
+  uint64_t mPacketCount;
+
+  // Serial number of the bitstream.
+  uint32_t mSerial;
+
+  // Ogg specific state.
+  ogg_stream_state mState;
+
+  // Queue of as yet undecoded packets. Packets are guaranteed to have
+  // a valid granulepos.
+  OggPacketQueue mPackets;
+
+  // Is the bitstream active; whether we're decoding and playing this bitstream.
+  bool mActive;
+
+  // True when all headers packets have been read.
+  bool mDoneReadingHeaders;
+
+  // Validation utility for vorbis-style tag names.
+  static bool IsValidVorbisTagName(nsCString& aName);
+
+  // Utility method to parse and add a vorbis-style comment
+  // to a metadata hash table. Most Ogg-encapsulated codecs
+  // use the vorbis comment format for metadata.
+  static bool AddVorbisComment(MetadataTags* aTags,
+                        const char* aComment,
+                        uint32_t aLength);
+
+protected:
+  // Constructs a new OggCodecState. aActive denotes whether the stream is
+  // active. For streams of unsupported or unknown types, aActive should be
+  // false.
+  OggCodecState(ogg_page* aBosPage, bool aActive);
+
+  // Deallocates all packets stored in mUnstamped, and clears the array.
+  void ClearUnstamped();
+
+  // Extracts packets out of mState until a data packet with a non -1
+  // granulepos is encountered, or no more packets are readable. Header
+  // packets are pushed into the packet queue immediately, and data packets
+  // are buffered in mUnstamped. Once a non -1 granulepos packet is read
+  // the granulepos of the packets in mUnstamped can be inferred, and they
+  // can be pushed over to mPackets. Used by PageIn() implementations in
+  // subclasses.
+  nsresult PacketOutUntilGranulepos(bool& aFoundGranulepos);
+
+  // Temporary buffer in which to store packets while we're reading packets
+  // in order to capture granulepos.
+  nsTArray<ogg_packet*> mUnstamped;
+
+private:
+  bool InternalInit();
+};
+
+class VorbisState : public OggCodecState
+{
+public:
+  explicit VorbisState(ogg_page* aBosPage);
+  virtual ~VorbisState();
+
+  CodecType GetType() override { return TYPE_VORBIS; }
+  bool DecodeHeader(ogg_packet* aPacket) override;
+  int64_t Time(int64_t granulepos) override;
+  int64_t PacketDuration(ogg_packet* aPacket) override;
+  bool Init() override;
+  nsresult Reset() override;
+  bool IsHeader(ogg_packet* aPacket) override;
+  nsresult PageIn(ogg_page* aPage) override;
+
+  // Return a hash table with tag metadata.
+  MetadataTags* GetTags() override;
+
+  // Returns the end time that a granulepos represents.
+  static int64_t Time(vorbis_info* aInfo, int64_t aGranulePos);
+
+  vorbis_info mInfo;
+  vorbis_comment mComment;
+  vorbis_dsp_state mDsp;
+  vorbis_block mBlock;
+
+private:
+
+  // Reconstructs the granulepos of Vorbis packets stored in the mUnstamped
+  // array.
+  nsresult ReconstructVorbisGranulepos();
+
+  // The "block size" of the previously decoded Vorbis packet, or 0 if we've
+  // not yet decoded anything. This is used to calculate the number of samples
+  // in a Vorbis packet, since each Vorbis packet depends on the previous
+  // packet while being decoded.
+  long mPrevVorbisBlockSize;
+
+  // Granulepos (end sample) of the last decoded Vorbis packet. This is used
+  // to calculate the Vorbis granulepos when we don't find a granulepos to
+  // back-propagate from.
+  int64_t mGranulepos;
+
+#ifdef VALIDATE_VORBIS_SAMPLE_CALCULATION
+  // When validating that we've correctly predicted Vorbis packets' number
+  // of samples, we store each packet's predicted number of samples in this
+  // map, and verify we decode the predicted number of samples.
+  std::map<ogg_packet*, long> mVorbisPacketSamples;
+#endif
+
+  // Records that aPacket is predicted to have aSamples samples.
+  // This function has no effect if VALIDATE_VORBIS_SAMPLE_CALCULATION
+  // is not defined.
+  void RecordVorbisPacketSamples(ogg_packet* aPacket, long aSamples);
+
+  // Verifies that aPacket has had its number of samples predicted.
+  // This function has no effect if VALIDATE_VORBIS_SAMPLE_CALCULATION
+  // is not defined.
+  void AssertHasRecordedPacketSamples(ogg_packet* aPacket);
+
+public:
+  // Asserts that the number of samples predicted for aPacket is aSamples.
+  // This function has no effect if VALIDATE_VORBIS_SAMPLE_CALCULATION
+  // is not defined.
+  void ValidateVorbisPacketSamples(ogg_packet* aPacket, long aSamples);
+
+};
+
+// Returns 1 if the Theora info struct is decoding a media of Theora
+// version (maj,min,sub) or later, otherwise returns 0.
+int TheoraVersion(th_info* info,
+                  unsigned char maj,
+                  unsigned char min,
+                  unsigned char sub);
+
+class TheoraState : public OggCodecState
+{
+public:
+  explicit TheoraState(ogg_page* aBosPage);
+  virtual ~TheoraState();
+
+  CodecType GetType() override { return TYPE_THEORA; }
+  bool DecodeHeader(ogg_packet* aPacket) override;
+  int64_t Time(int64_t granulepos) override;
+  int64_t StartTime(int64_t granulepos) override;
+  int64_t PacketDuration(ogg_packet* aPacket) override;
+  bool Init() override;
+  bool IsHeader(ogg_packet* aPacket) override;
+  bool IsKeyframe(ogg_packet* aPacket) override;
+  nsresult PageIn(ogg_page* aPage) override;
+
+  // Returns the maximum number of microseconds which a keyframe can be offset
+  // from any given interframe.
+  int64_t MaxKeyframeOffset();
+
+  // Returns the end time that a granulepos represents.
+  static int64_t Time(th_info* aInfo, int64_t aGranulePos);
+
+  th_info mInfo;
+  th_comment mComment;
+  th_setup_info* mSetup;
+  th_dec_ctx* mCtx;
+
+  float mPixelAspectRatio;
+
+private:
+
+  // Reconstructs the granulepos of Theora packets stored in the
+  // mUnstamped array. mUnstamped must be filled with consecutive packets from
+  // the stream, with the last packet having a known granulepos. Using this
+  // known granulepos, and the known frame numbers, we recover the granulepos
+  // of all frames in the array. This enables us to determine their timestamps.
+  void ReconstructTheoraGranulepos();
+
+};
+
+class OpusState : public OggCodecState
+{
+public:
+  explicit OpusState(ogg_page* aBosPage);
+  virtual ~OpusState();
+
+  CodecType GetType() override { return TYPE_OPUS; }
+  bool DecodeHeader(ogg_packet* aPacket) override;
+  int64_t Time(int64_t aGranulepos) override;
+  int64_t PacketDuration(ogg_packet* aPacket) override;
+  bool Init() override;
+  nsresult Reset() override;
+  nsresult Reset(bool aStart);
+  bool IsHeader(ogg_packet* aPacket) override;
+  nsresult PageIn(ogg_page* aPage) override;
+  already_AddRefed<MediaRawData> PacketOutAsMediaRawData() override;
+  // Returns the end time that a granulepos represents.
+  static int64_t Time(int aPreSkip, int64_t aGranulepos);
+
+  // Various fields from the Ogg Opus header.
+  int mRate;        // Sample rate the decoder uses (always 48 kHz).
+  int mChannels;    // Number of channels the stream encodes.
+  uint16_t mPreSkip; // Number of samples to strip after decoder reset.
+#ifdef MOZ_SAMPLE_TYPE_FLOAT32
+  float mGain;      // Gain to apply to decoder output.
+#else
+  int32_t mGain_Q16; // Gain to apply to the decoder output.
+#endif
+
+  nsAutoPtr<OpusParser> mParser;
+  OpusMSDecoder* mDecoder;
+
+  int mSkip;        // Number of samples left to trim before playback.
+  // Granule position (end sample) of the last decoded Opus packet. This is
+  // used to calculate the amount we should trim from the last packet.
+  int64_t mPrevPacketGranulepos;
+
+  // Construct and return a table of tags from the metadata header.
+  MetadataTags* GetTags() override;
+
+private:
+
+  // Reconstructs the granulepos of Opus packets stored in the
+  // mUnstamped array. mUnstamped must be filled with consecutive packets from
+  // the stream, with the last packet having a known granulepos. Using this
+  // known granulepos, and the known frame numbers, we recover the granulepos
+  // of all frames in the array. This enables us to determine their timestamps.
+  bool ReconstructOpusGranulepos();
+
+  // Granule position (end sample) of the last decoded Opus page. This is
+  // used to calculate the Opus per-packet granule positions on the last page,
+  // where we may need to trim some samples from the end.
+  int64_t mPrevPageGranulepos;
+
+};
+
+// Constructs a 32bit version number out of two 16 bit major,minor
+// version numbers.
+#define SKELETON_VERSION(major, minor) (((major)<<16)|(minor))
+
+enum EMsgHeaderType {
+  eContentType,
+  eRole,
+  eName,
+  eLanguage,
+  eTitle,
+  eDisplayHint,
+  eAltitude,
+  eTrackOrder,
+  eTrackDependencies
+};
+
+typedef struct
+{
+  const char* mPatternToRecognize;
+  EMsgHeaderType mMsgHeaderType;
+} FieldPatternType;
+
+// Stores the message information for different logical bitstream.
+typedef struct
+{
+  nsClassHashtable<nsUint32HashKey, nsCString> mValuesStore;
+} MessageField;
+
+class SkeletonState : public OggCodecState
+{
+public:
+  explicit SkeletonState(ogg_page* aBosPage);
+  ~SkeletonState();
+
+  nsClassHashtable<nsUint32HashKey, MessageField> mMsgFieldStore;
+
+  CodecType GetType() override { return TYPE_SKELETON; }
+  bool DecodeHeader(ogg_packet* aPacket) override;
+  int64_t Time(int64_t granulepos) override { return -1; }
+  bool IsHeader(ogg_packet* aPacket) override { return true; }
+
+  // Return true if the given time (in milliseconds) is within
+  // the presentation time defined in the skeleton track.
+  bool IsPresentable(int64_t aTime) { return aTime >= mPresentationTime; }
+
+  // Stores the offset of the page on which a keyframe starts,
+  // and its presentation time.
+  class nsKeyPoint
+  {
+  public:
+    nsKeyPoint()
+      : mOffset(INT64_MAX)
+      , mTime(INT64_MAX) {}
+
+    nsKeyPoint(int64_t aOffset, int64_t aTime)
+      : mOffset(aOffset)
+      ,mTime(aTime) {}
+
+    // Offset from start of segment/link-in-the-chain in bytes.
+    int64_t mOffset;
+
+    // Presentation time in usecs.
+    int64_t mTime;
+
+    bool IsNull()
+    {
+      return mOffset == INT64_MAX && mTime == INT64_MAX;
+    }
+  };
+
+  // Stores a keyframe's byte-offset, presentation time and the serialno
+  // of the stream it belongs to.
+  class nsSeekTarget
+  {
+  public:
+    nsSeekTarget() : mSerial(0) {}
+    nsKeyPoint mKeyPoint;
+    uint32_t mSerial;
+    bool IsNull()
+    {
+      return mKeyPoint.IsNull() && mSerial == 0;
+    }
+  };
+
+  // Determines from the seek index the keyframe which you must seek back to
+  // in order to get all keyframes required to render all streams with
+  // serialnos in aTracks, at time aTarget.
+  nsresult IndexedSeekTarget(int64_t aTarget,
+                             nsTArray<uint32_t>& aTracks,
+                             nsSeekTarget& aResult);
+
+  bool HasIndex() const
+  {
+    return mIndex.Count() > 0;
+  }
+
+  // Returns the duration of the active tracks in the media, if we have
+  // an index. aTracks must be filled with the serialnos of the active tracks.
+  // The duration is calculated as the greatest end time of all active tracks,
+  // minus the smalled start time of all the active tracks.
+  nsresult GetDuration(const nsTArray<uint32_t>& aTracks, int64_t& aDuration);
+
+private:
+
+  // Decodes an index packet. Returns false on failure.
+  bool DecodeIndex(ogg_packet* aPacket);
+  // Decodes an fisbone packet. Returns false on failure.
+  bool DecodeFisbone(ogg_packet* aPacket);
+
+  // Gets the keypoint you must seek to in order to get the keyframe required
+  // to render the stream at time aTarget on stream with serial aSerialno.
+  nsresult IndexedSeekTargetForTrack(uint32_t aSerialno,
+                                     int64_t aTarget,
+                                     nsKeyPoint& aResult);
+
+  // Version of the decoded skeleton track, as per the SKELETON_VERSION macro.
+  uint32_t mVersion;
+
+  // Presentation time of the resource in milliseconds
+  int64_t mPresentationTime;
+
+  // Length of the resource in bytes.
+  int64_t mLength;
+
+  // Stores the keyframe index and duration information for a particular
+  // stream.
+  class nsKeyFrameIndex
+  {
+  public:
+
+    nsKeyFrameIndex(int64_t aStartTime, int64_t aEndTime)
+      : mStartTime(aStartTime)
+      , mEndTime(aEndTime)
+    {
+      MOZ_COUNT_CTOR(nsKeyFrameIndex);
+    }
+
+    ~nsKeyFrameIndex()
+    {
+      MOZ_COUNT_DTOR(nsKeyFrameIndex);
+    }
+
+    void Add(int64_t aOffset, int64_t aTimeMs)
+    {
+      mKeyPoints.AppendElement(nsKeyPoint(aOffset, aTimeMs));
+    }
+
+    const nsKeyPoint& Get(uint32_t aIndex) const
+    {
+      return mKeyPoints[aIndex];
+    }
+
+    uint32_t Length() const
+    {
+      return mKeyPoints.Length();
+    }
+
+    // Presentation time of the first sample in this stream in usecs.
+    const int64_t mStartTime;
+
+    // End time of the last sample in this stream in usecs.
+    const int64_t mEndTime;
+
+  private:
+    nsTArray<nsKeyPoint> mKeyPoints;
+  };
+
+  // Maps Ogg serialnos to the index-keypoint list.
+  nsClassHashtable<nsUint32HashKey, nsKeyFrameIndex> mIndex;
+};
+
+class FlacState : public OggCodecState
+{
+public:
+  explicit FlacState(ogg_page* aBosPage);
+
+  CodecType GetType() override { return TYPE_FLAC; }
+  bool DecodeHeader(ogg_packet* aPacket) override;
+  int64_t Time(int64_t granulepos) override;
+  int64_t PacketDuration(ogg_packet* aPacket) override;
+  bool IsHeader(ogg_packet* aPacket) override;
+  nsresult PageIn(ogg_page* aPage) override;
+
+  // Return a hash table with tag metadata.
+  MetadataTags* GetTags() override;
+
+  const AudioInfo& Info();
+
+private:
+  bool ReconstructFlacGranulepos(void);
+
+  FlacFrameParser mParser;
+};
+
+} // namespace mozilla
+
+// This allows the use of nsAutoRefs for an ogg_packet that properly free the
+// contents of the packet.
+template <>
+class nsAutoRefTraits<ogg_packet> : public nsPointerRefTraits<ogg_packet>
+{
+public:
+  static void Release(ogg_packet* aPacket)
+  {
+    mozilla::OggCodecState::ReleasePacket(aPacket);
+  }
+};
+
+
+#endif
diff --git a/dom/media/ogg/OggCodecStore.cpp b/dom/media/ogg/OggCodecStore.cpp
new file mode 100644
index 0000000000..528932dd02
--- /dev/null
+++ b/dom/media/ogg/OggCodecStore.cpp
@@ -0,0 +1,37 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim:set ts=2 sw=2 sts=2 et cindent: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "mozilla/DebugOnly.h"
+
+#include "OggCodecStore.h"
+
+namespace mozilla {
+
+OggCodecStore::OggCodecStore()
+: mMonitor("CodecStore")
+{
+}
+
+void OggCodecStore::Add(uint32_t serial, OggCodecState* codecState)
+{
+  MonitorAutoLock mon(mMonitor);
+  mCodecStates.Put(serial, codecState);
+}
+
+bool OggCodecStore::Contains(uint32_t serial)
+{
+  MonitorAutoLock mon(mMonitor);
+  return mCodecStates.Get(serial, nullptr);
+}
+
+OggCodecState* OggCodecStore::Get(uint32_t serial)
+{
+  MonitorAutoLock mon(mMonitor);
+  return mCodecStates.Get(serial);
+}
+
+} // namespace mozilla
+
diff --git a/dom/media/ogg/OggCodecStore.h b/dom/media/ogg/OggCodecStore.h
new file mode 100644
index 0000000000..2d8fd58307
--- /dev/null
+++ b/dom/media/ogg/OggCodecStore.h
@@ -0,0 +1,38 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim:set ts=2 sw=2 sts=2 et cindent: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+#if !defined(OggCodecStore_h_)
+#define OggCodecStore_h_
+
+#include <ogg/ogg.h>
+
+#include "OggCodecState.h"
+#include "VideoUtils.h"
+#include "mozilla/Monitor.h"
+
+namespace mozilla {
+
+// Thread safe container to store the codec information and the serial for each
+// streams.
+class OggCodecStore
+{
+  public:
+    OggCodecStore();
+    void Add(uint32_t serial, OggCodecState* codecState);
+    bool Contains(uint32_t serial);
+    OggCodecState* Get(uint32_t serial);
+    bool IsKnownStream(uint32_t aSerial);
+
+  private:
+    // Maps Ogg serialnos to OggStreams.
+    nsClassHashtable<nsUint32HashKey, OggCodecState> mCodecStates;
+
+    // Protects the |mCodecStates| and the |mKnownStreams| members.
+    Monitor mMonitor;
+};
+
+} // namespace mozilla
+
+#endif
diff --git a/dom/media/ogg/OggDecoder.cpp b/dom/media/ogg/OggDecoder.cpp
new file mode 100644
index 0000000000..2631b1cde2
--- /dev/null
+++ b/dom/media/ogg/OggDecoder.cpp
@@ -0,0 +1,79 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim:set ts=2 sw=2 sts=2 et cindent: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "MediaPrefs.h"
+#include "MediaDecoderStateMachine.h"
+#include "MediaFormatReader.h"
+#include "OggDemuxer.h"
+#include "OggDecoder.h"
+#include "nsContentTypeParser.h"
+
+namespace mozilla {
+
+MediaDecoderStateMachine* OggDecoder::CreateStateMachine()
+{
+  RefPtr<OggDemuxer> demuxer = new OggDemuxer(GetResource());
+  RefPtr<MediaFormatReader> reader =
+    new MediaFormatReader(this, demuxer, GetVideoFrameContainer());
+  demuxer->SetChainingEvents(&reader->TimedMetadataProducer(),
+                             &reader->MediaNotSeekableProducer());
+  return new MediaDecoderStateMachine(this, reader);
+}
+
+/* static */
+bool
+OggDecoder::IsEnabled()
+{
+  return MediaPrefs::OggEnabled();
+}
+
+/* static */
+bool
+OggDecoder::CanHandleMediaType(const nsACString& aMIMETypeExcludingCodecs,
+                               const nsAString& aCodecs)
+{
+  if (!IsEnabled()) {
+    return false;
+  }
+
+  const bool isOggAudio = aMIMETypeExcludingCodecs.EqualsASCII("audio/ogg");
+  const bool isOggVideo =
+    aMIMETypeExcludingCodecs.EqualsASCII("video/ogg") ||
+    aMIMETypeExcludingCodecs.EqualsASCII("application/ogg");
+
+  if (!isOggAudio && !isOggVideo) {
+    return false;
+  }
+
+  nsTArray<nsCString> codecMimes;
+  if (aCodecs.IsEmpty()) {
+    // WebM guarantees that the only codecs it contained are vp8, vp9, opus or vorbis.
+    return true;
+  }
+  // Verify that all the codecs specified are ones that we expect that
+  // we can play.
+  nsTArray<nsString> codecs;
+  if (!ParseCodecsString(aCodecs, codecs)) {
+    return false;
+  }
+  for (const nsString& codec : codecs) {
+    if ((IsOpusEnabled() && codec.EqualsLiteral("opus")) ||
+        codec.EqualsLiteral("vorbis") ||
+        (MediaPrefs::FlacInOgg() && codec.EqualsLiteral("flac"))) {
+      continue;
+    }
+    // Note: Only accept Theora in a video content type, not in an audio
+    // content type.
+    if (isOggVideo && codec.EqualsLiteral("theora")) {
+      continue;
+    }
+    // Some unsupported codec.
+    return false;
+  }
+  return true;
+}
+
+} // namespace mozilla
diff --git a/dom/media/ogg/OggDecoder.h b/dom/media/ogg/OggDecoder.h
new file mode 100644
index 0000000000..3a98f29181
--- /dev/null
+++ b/dom/media/ogg/OggDecoder.h
@@ -0,0 +1,61 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim:set ts=2 sw=2 sts=2 et cindent: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+#if !defined(OggDecoder_h_)
+#define OggDecoder_h_
+
+#include "MediaDecoder.h"
+
+namespace mozilla {
+
+class OggDecoder : public MediaDecoder
+{
+public:
+  explicit OggDecoder(MediaDecoderOwner* aOwner)
+    : MediaDecoder(aOwner)
+    , mShutdownBitMonitor("mShutdownBitMonitor")
+    , mShutdownBit(false)
+  {}
+
+  MediaDecoder* Clone(MediaDecoderOwner* aOwner) override {
+    if (!IsOggEnabled()) {
+      return nullptr;
+    }
+    return new OggDecoder(aOwner);
+  }
+  MediaDecoderStateMachine* CreateStateMachine() override;
+
+  // For yucky legacy reasons, the ogg decoder needs to do a cross-thread read
+  // to check for shutdown while it hogs its own task queue. We don't want to
+  // protect the general state with a lock, so we make a special copy and a
+  // special-purpose lock. This method may be called on any thread.
+  bool IsOggDecoderShutdown() override
+  {
+    MonitorAutoLock lock(mShutdownBitMonitor);
+    return mShutdownBit;
+  }
+
+  // Returns true if aMIMEType is a type that we think we can render with the
+  // a platform decoder backend. If aCodecs is non emtpy, it is filled
+  // with a comma-delimited list of codecs to check support for.
+  static bool CanHandleMediaType(const nsACString& aMIMETypeExcludingCodecs,
+                                 const nsAString& aCodecs);
+
+  static bool IsEnabled();
+
+protected:
+  void ShutdownBitChanged() override
+  {
+    MonitorAutoLock lock(mShutdownBitMonitor);
+    mShutdownBit = mStateMachineIsShutdown;
+  }
+
+  Monitor mShutdownBitMonitor;
+  bool mShutdownBit;
+};
+
+} // namespace mozilla
+
+#endif
diff --git a/dom/media/ogg/OggDemuxer.cpp b/dom/media/ogg/OggDemuxer.cpp
new file mode 100644
index 0000000000..591a5248fc
--- /dev/null
+++ b/dom/media/ogg/OggDemuxer.cpp
@@ -0,0 +1,2194 @@
+ /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim:set ts=2 sw=2 sts=2 et cindent: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsError.h"
+#include "MediaDecoderStateMachine.h"
+#include "AbstractMediaDecoder.h"
+#include "OggDemuxer.h"
+#include "OggCodecState.h"
+#include "mozilla/Atomics.h"
+#include "mozilla/PodOperations.h"
+#include "mozilla/SharedThreadPool.h"
+#include "mozilla/Telemetry.h"
+#include "mozilla/TimeStamp.h"
+#include "MediaDataDemuxer.h"
+#include "nsAutoRef.h"
+#include "XiphExtradata.h"
+#include "MediaPrefs.h"
+
+#include <algorithm>
+
+extern mozilla::LazyLogModule gMediaDemuxerLog;
+#define OGG_DEBUG(arg, ...) MOZ_LOG(gMediaDemuxerLog, mozilla::LogLevel::Debug, ("OggDemuxer(%p)::%s: " arg, this, __func__, ##__VA_ARGS__))
+
+// Un-comment to enable logging of seek bisections.
+//#define SEEK_LOGGING
+#ifdef SEEK_LOGGING
+#define SEEK_LOG(type, msg) MOZ_LOG(gMediaDemuxerLog, type, msg)
+#else
+#define SEEK_LOG(type, msg)
+#endif
+
+namespace mozilla
+{
+
+using media::TimeUnit;
+using media::TimeInterval;
+using media::TimeIntervals;
+
+// The number of microseconds of "fuzz" we use in a bisection search over
+// HTTP. When we're seeking with fuzz, we'll stop the search if a bisection
+// lands between the seek target and OGG_SEEK_FUZZ_USECS microseconds before the
+// seek target.  This is becaue it's usually quicker to just keep downloading
+// from an exisiting connection than to do another bisection inside that
+// small range, which would open a new HTTP connetion.
+static const uint32_t OGG_SEEK_FUZZ_USECS = 500000;
+
+// The number of microseconds of "pre-roll" we use for Opus streams.
+// The specification recommends 80 ms.
+static const int64_t OGG_SEEK_OPUS_PREROLL = 80 * USECS_PER_MS;
+
+static Atomic<uint32_t> sStreamSourceID(0u);
+
+class OggHeaders
+{
+public:
+  OggHeaders() {}
+  ~OggHeaders()
+  {
+    for (size_t i = 0; i < mHeaders.Length(); i++) {
+      delete[] mHeaders[i];
+    }
+  }
+
+  void AppendPacket(const ogg_packet* aPacket)
+  {
+    size_t packetSize = aPacket->bytes;
+    unsigned char* packetData = new unsigned char[packetSize];
+    memcpy(packetData, aPacket->packet, packetSize);
+    mHeaders.AppendElement(packetData);
+    mHeaderLens.AppendElement(packetSize);
+  }
+
+  nsTArray<const unsigned char*> mHeaders;
+  nsTArray<size_t> mHeaderLens;
+};
+
+// Return the corresponding category in aKind based on the following specs.
+// (https://www.whatwg.org/specs/web-apps/current-
+// work/multipage/embedded-content.html#dom-audiotrack-kind) &
+// (http://wiki.xiph.org/SkeletonHeaders)
+const nsString
+OggDemuxer::GetKind(const nsCString& aRole)
+{
+  if (aRole.Find("audio/main") != -1 || aRole.Find("video/main") != -1) {
+    return NS_LITERAL_STRING("main");
+  } else if (aRole.Find("audio/alternate") != -1 ||
+             aRole.Find("video/alternate") != -1) {
+    return NS_LITERAL_STRING("alternative");
+  } else if (aRole.Find("audio/audiodesc") != -1) {
+    return NS_LITERAL_STRING("descriptions");
+  } else if (aRole.Find("audio/described") != -1) {
+    return NS_LITERAL_STRING("main-desc");
+  } else if (aRole.Find("audio/dub") != -1) {
+    return NS_LITERAL_STRING("translation");
+  } else if (aRole.Find("audio/commentary") != -1) {
+    return NS_LITERAL_STRING("commentary");
+  } else if (aRole.Find("video/sign") != -1) {
+    return NS_LITERAL_STRING("sign");
+  } else if (aRole.Find("video/captioned") != -1) {
+    return NS_LITERAL_STRING("captions");
+  } else if (aRole.Find("video/subtitled") != -1) {
+    return NS_LITERAL_STRING("subtitles");
+  }
+  return EmptyString();
+}
+
+void
+OggDemuxer::InitTrack(MessageField* aMsgInfo,
+                      TrackInfo* aInfo,
+                      bool aEnable)
+{
+  MOZ_ASSERT(aMsgInfo);
+  MOZ_ASSERT(aInfo);
+
+  nsCString* sName = aMsgInfo->mValuesStore.Get(eName);
+  nsCString* sRole = aMsgInfo->mValuesStore.Get(eRole);
+  nsCString* sTitle = aMsgInfo->mValuesStore.Get(eTitle);
+  nsCString* sLanguage = aMsgInfo->mValuesStore.Get(eLanguage);
+  aInfo->Init(sName? NS_ConvertUTF8toUTF16(*sName):EmptyString(),
+              sRole? GetKind(*sRole):EmptyString(),
+              sTitle? NS_ConvertUTF8toUTF16(*sTitle):EmptyString(),
+              sLanguage? NS_ConvertUTF8toUTF16(*sLanguage):EmptyString(),
+              aEnable);
+}
+
+OggDemuxer::OggDemuxer(MediaResource* aResource)
+  : mTheoraState(nullptr)
+  , mVorbisState(nullptr)
+  , mOpusState(nullptr)
+  , mFlacState(nullptr)
+  , mOpusEnabled(MediaDecoder::IsOpusEnabled())
+  , mSkeletonState(nullptr)
+  , mAudioOggState(aResource)
+  , mVideoOggState(aResource)
+  , mVorbisSerial(0)
+  , mOpusSerial(0)
+  , mTheoraSerial(0)
+  , mFlacSerial(0)
+  , mOpusPreSkip(0)
+  , mIsChained(false)
+  , mTimedMetadataEvent(nullptr)
+  , mOnSeekableEvent(nullptr)
+{
+  MOZ_COUNT_CTOR(OggDemuxer);
+  PodZero(&mTheoraInfo);
+}
+
+OggDemuxer::~OggDemuxer()
+{
+  MOZ_COUNT_DTOR(OggDemuxer);
+  Reset(TrackInfo::kAudioTrack);
+  Reset(TrackInfo::kVideoTrack);
+  if (HasAudio() || HasVideo()) {
+    // If we were able to initialize our decoders, report whether we encountered
+    // a chained stream or not.
+    bool isChained = mIsChained;
+    void* ptr = this;
+    nsCOMPtr<nsIRunnable> task = NS_NewRunnableFunction([ptr, isChained]() -> void {
+      // We can't use OGG_DEBUG here because it implicitly refers to `this`,
+      // which we can't capture in this runnable.
+      MOZ_LOG(gMediaDemuxerLog, mozilla::LogLevel::Debug,
+              ("OggDemuxer(%p)::%s: Reporting telemetry MEDIA_OGG_LOADED_IS_CHAINED=%d",
+               ptr, __func__, isChained));
+      Telemetry::Accumulate(Telemetry::ID::MEDIA_OGG_LOADED_IS_CHAINED, isChained);
+    });
+    AbstractThread::MainThread()->Dispatch(task.forget());
+  }
+}
+
+void
+OggDemuxer::SetChainingEvents(TimedMetadataEventProducer* aMetadataEvent,
+                              MediaEventProducer<void>* aOnSeekableEvent)
+{
+  mTimedMetadataEvent = aMetadataEvent;
+  mOnSeekableEvent = aOnSeekableEvent;
+}
+
+
+bool
+OggDemuxer::HasAudio()
+const
+{
+  return mVorbisState || mOpusState || mFlacState;
+}
+
+bool
+OggDemuxer::HasVideo()
+const
+{
+  return mTheoraState;
+}
+
+bool
+OggDemuxer::HaveStartTime()
+const
+{
+  return mStartTime.isSome();
+}
+
+int64_t
+OggDemuxer::StartTime() const
+{
+  return mStartTime.refOr(0);
+}
+
+bool
+OggDemuxer::HaveStartTime(TrackInfo::TrackType aType)
+{
+  return OggState(aType).mStartTime.isSome();
+}
+
+int64_t
+OggDemuxer::StartTime(TrackInfo::TrackType aType)
+{
+  return OggState(aType).mStartTime.refOr(TimeUnit::FromMicroseconds(0)).ToMicroseconds();
+}
+
+RefPtr<OggDemuxer::InitPromise>
+OggDemuxer::Init()
+{
+  int ret = ogg_sync_init(OggSyncState(TrackInfo::kAudioTrack));
+  if (ret != 0) {
+    return InitPromise::CreateAndReject(NS_ERROR_OUT_OF_MEMORY, __func__);
+  }
+  ret = ogg_sync_init(OggSyncState(TrackInfo::kVideoTrack));
+  if (ret != 0) {
+    return InitPromise::CreateAndReject(NS_ERROR_OUT_OF_MEMORY, __func__);
+  }
+  if (ReadMetadata() != NS_OK) {
+    return InitPromise::CreateAndReject(NS_ERROR_DOM_MEDIA_METADATA_ERR, __func__);
+  }
+
+  if (!GetNumberTracks(TrackInfo::kAudioTrack) &&
+      !GetNumberTracks(TrackInfo::kVideoTrack)) {
+    return InitPromise::CreateAndReject(NS_ERROR_DOM_MEDIA_METADATA_ERR, __func__);
+  }
+
+  return InitPromise::CreateAndResolve(NS_OK, __func__);
+}
+
+bool
+OggDemuxer::HasTrackType(TrackInfo::TrackType aType) const
+{
+  return !!GetNumberTracks(aType);
+}
+
+OggCodecState*
+OggDemuxer::GetTrackCodecState(TrackInfo::TrackType aType) const
+{
+  switch(aType) {
+    case TrackInfo::kAudioTrack:
+      if (mVorbisState) {
+        return mVorbisState;
+      } else if (mOpusState) {
+        return mOpusState;
+      } else {
+        return mFlacState;
+      }
+    case TrackInfo::kVideoTrack:
+      return mTheoraState;
+    default:
+      return 0;
+  }
+}
+
+TrackInfo::TrackType
+OggDemuxer::GetCodecStateType(OggCodecState* aState) const
+{
+  switch (aState->GetType()) {
+    case OggCodecState::TYPE_THEORA:
+      return TrackInfo::kVideoTrack;
+    case OggCodecState::TYPE_OPUS:
+    case OggCodecState::TYPE_VORBIS:
+    case OggCodecState::TYPE_FLAC:
+      return TrackInfo::kAudioTrack;
+    default:
+      return TrackInfo::kUndefinedTrack;
+  }
+}
+
+uint32_t
+OggDemuxer::GetNumberTracks(TrackInfo::TrackType aType) const
+{
+  switch(aType) {
+    case TrackInfo::kAudioTrack:
+      return HasAudio() ? 1 : 0;
+    case TrackInfo::kVideoTrack:
+      return HasVideo() ? 1 : 0;
+    default:
+      return 0;
+  }
+}
+
+UniquePtr<TrackInfo>
+OggDemuxer::GetTrackInfo(TrackInfo::TrackType aType, size_t aTrackNumber) const
+{
+  switch(aType) {
+    case TrackInfo::kAudioTrack:
+      return mInfo.mAudio.Clone();
+    case TrackInfo::kVideoTrack:
+      return mInfo.mVideo.Clone();
+    default:
+      return nullptr;
+  }
+}
+
+already_AddRefed<MediaTrackDemuxer>
+OggDemuxer::GetTrackDemuxer(TrackInfo::TrackType aType, uint32_t aTrackNumber)
+{
+  if (GetNumberTracks(aType) <= aTrackNumber) {
+    return nullptr;
+  }
+  RefPtr<OggTrackDemuxer> e = new OggTrackDemuxer(this, aType, aTrackNumber);
+  mDemuxers.AppendElement(e);
+
+  return e.forget();
+}
+
+nsresult
+OggDemuxer::Reset(TrackInfo::TrackType aType)
+{
+  // Discard any previously buffered packets/pages.
+  ogg_sync_reset(OggSyncState(aType));
+  OggCodecState* trackState = GetTrackCodecState(aType);
+  if (trackState) {
+    return trackState->Reset();
+  }
+  OggState(aType).mNeedKeyframe = true;
+  return NS_OK;
+}
+
+bool
+OggDemuxer::ReadHeaders(TrackInfo::TrackType aType,
+                        OggCodecState* aState,
+                        OggHeaders& aHeaders)
+{
+  while (!aState->DoneReadingHeaders()) {
+    DemuxUntilPacketAvailable(aType, aState);
+    ogg_packet* packet = aState->PacketOut();
+    if (!packet) {
+      OGG_DEBUG("Ran out of header packets early; deactivating stream %ld", aState->mSerial);
+      aState->Deactivate();
+      return false;
+    }
+
+    // Save a copy of the header packet for the decoder to use later;
+    // OggCodecState::DecodeHeader will free it when processing locally.
+    aHeaders.AppendPacket(packet);
+
+    // Local OggCodecState needs to decode headers in order to process
+    // packet granulepos -> time mappings, etc.
+    if (!aState->DecodeHeader(packet)) {
+      OGG_DEBUG("Failed to decode ogg header packet; deactivating stream %ld", aState->mSerial);
+      aState->Deactivate();
+      return false;
+    }
+  }
+
+  return aState->Init();
+}
+
+void
+OggDemuxer::BuildSerialList(nsTArray<uint32_t>& aTracks)
+{
+  // Obtaining seek index information for currently active bitstreams.
+  if (HasVideo()) {
+    aTracks.AppendElement(mTheoraState->mSerial);
+  }
+  if (HasAudio()) {
+    if (mVorbisState) {
+      aTracks.AppendElement(mVorbisState->mSerial);
+    } else if (mOpusState) {
+      aTracks.AppendElement(mOpusState->mSerial);
+    }
+  }
+}
+
+void
+OggDemuxer::SetupTargetTheora(TheoraState* aTheoraState, OggHeaders& aHeaders)
+{
+  if (mTheoraState) {
+    mTheoraState->Reset();
+  }
+
+  nsIntRect picture = nsIntRect(aTheoraState->mInfo.pic_x,
+                                aTheoraState->mInfo.pic_y,
+                                aTheoraState->mInfo.pic_width,
+                                aTheoraState->mInfo.pic_height);
+
+  nsIntSize displaySize = nsIntSize(aTheoraState->mInfo.pic_width,
+                                    aTheoraState->mInfo.pic_height);
+
+  // Apply the aspect ratio to produce the intrinsic display size we report
+  // to the element.
+  ScaleDisplayByAspectRatio(displaySize, aTheoraState->mPixelAspectRatio);
+
+  nsIntSize frameSize(aTheoraState->mInfo.frame_width,
+                      aTheoraState->mInfo.frame_height);
+  if (IsValidVideoRegion(frameSize, picture, displaySize)) {
+    // Video track's frame sizes will not overflow. Activate the video track.
+    mInfo.mVideo.mMimeType = "video/theora";
+    mInfo.mVideo.mDisplay = displaySize;
+    mInfo.mVideo.mImage = frameSize;
+    mInfo.mVideo.SetImageRect(picture);
+
+    // Copy Theora info data for time computations on other threads.
+    memcpy(&mTheoraInfo, &aTheoraState->mInfo, sizeof(mTheoraInfo));
+
+    // Save header packets for the decoder
+    if (!XiphHeadersToExtradata(mInfo.mVideo.mCodecSpecificConfig,
+                                aHeaders.mHeaders, aHeaders.mHeaderLens)) {
+      return;
+    }
+
+    mTheoraState = aTheoraState;
+    mTheoraSerial = aTheoraState->mSerial;
+  }
+}
+
+void
+OggDemuxer::SetupTargetVorbis(VorbisState* aVorbisState, OggHeaders& aHeaders)
+{
+  if (mVorbisState) {
+    mVorbisState->Reset();
+  }
+
+  // Copy Vorbis info data for time computations on other threads.
+  memcpy(&mVorbisInfo, &aVorbisState->mInfo, sizeof(mVorbisInfo));
+  mVorbisInfo.codec_setup = nullptr;
+
+  mInfo.mAudio.mMimeType = "audio/vorbis";
+  mInfo.mAudio.mRate = aVorbisState->mInfo.rate;
+  mInfo.mAudio.mChannels = aVorbisState->mInfo.channels;
+
+  // Save header packets for the decoder
+  if (!XiphHeadersToExtradata(mInfo.mAudio.mCodecSpecificConfig,
+                              aHeaders.mHeaders, aHeaders.mHeaderLens)) {
+    return;
+  }
+
+  mVorbisState = aVorbisState;
+  mVorbisSerial = aVorbisState->mSerial;
+}
+
+void
+OggDemuxer::SetupTargetOpus(OpusState* aOpusState, OggHeaders& aHeaders)
+{
+  if (mOpusState) {
+    mOpusState->Reset();
+  }
+
+  mInfo.mAudio.mMimeType = "audio/opus";
+  mInfo.mAudio.mRate = aOpusState->mRate;
+  mInfo.mAudio.mChannels = aOpusState->mChannels;
+
+  // Save preskip & the first header packet for the Opus decoder
+  uint64_t preSkip = aOpusState->Time(0, aOpusState->mPreSkip);
+  uint8_t c[sizeof(preSkip)];
+  BigEndian::writeUint64(&c[0], preSkip);
+  mInfo.mAudio.mCodecSpecificConfig->AppendElements(&c[0], sizeof(preSkip));
+  mInfo.mAudio.mCodecSpecificConfig->AppendElements(aHeaders.mHeaders[0],
+                                                    aHeaders.mHeaderLens[0]);
+
+  mOpusState = aOpusState;
+  mOpusSerial = aOpusState->mSerial;
+  mOpusPreSkip = aOpusState->mPreSkip;
+}
+
+void
+OggDemuxer::SetupTargetFlac(FlacState* aFlacState, OggHeaders& aHeaders)
+{
+  if (mFlacState) {
+    mFlacState->Reset();
+  }
+
+  mInfo.mAudio = aFlacState->Info();
+  mFlacState = aFlacState;
+  mFlacSerial = aFlacState->mSerial;
+}
+
+void
+OggDemuxer::SetupTargetSkeleton()
+{
+  // Setup skeleton related information after mVorbisState & mTheroState
+  // being set (if they exist).
+  if (mSkeletonState) {
+    OggHeaders headers;
+    if (!HasAudio() && !HasVideo()) {
+      // We have a skeleton track, but no audio or video, may as well disable
+      // the skeleton, we can't do anything useful with this media.
+      OGG_DEBUG("Deactivating skeleton stream %ld", mSkeletonState->mSerial);
+      mSkeletonState->Deactivate();
+    } else if (ReadHeaders(TrackInfo::kAudioTrack, mSkeletonState, headers) &&
+               mSkeletonState->HasIndex()) {
+      // We don't particularly care about which track we are currently using
+      // as both MediaResource points to the same content.
+      // Extract the duration info out of the index, so we don't need to seek to
+      // the end of resource to get it.
+      nsTArray<uint32_t> tracks;
+      BuildSerialList(tracks);
+      int64_t duration = 0;
+      if (NS_SUCCEEDED(mSkeletonState->GetDuration(tracks, duration))) {
+        OGG_DEBUG("Got duration from Skeleton index %lld", duration);
+        mInfo.mMetadataDuration.emplace(TimeUnit::FromMicroseconds(duration));
+      }
+    }
+  }
+}
+
+void
+OggDemuxer::SetupMediaTracksInfo(const nsTArray<uint32_t>& aSerials)
+{
+  // For each serial number
+  // 1. Retrieve a codecState from mCodecStore by this serial number.
+  // 2. Retrieve a message field from mMsgFieldStore by this serial number.
+  // 3. For now, skip if the serial number refers to a non-primary bitstream.
+  // 4. Setup track and other audio/video related information per different types.
+  for (size_t i = 0; i < aSerials.Length(); i++) {
+    uint32_t serial = aSerials[i];
+    OggCodecState* codecState = mCodecStore.Get(serial);
+
+    MessageField* msgInfo = nullptr;
+    if (mSkeletonState && mSkeletonState->mMsgFieldStore.Contains(serial)) {
+      mSkeletonState->mMsgFieldStore.Get(serial, &msgInfo);
+    }
+
+    if (codecState->GetType() == OggCodecState::TYPE_THEORA) {
+      TheoraState* theoraState = static_cast<TheoraState*>(codecState);
+      if (!(mTheoraState && mTheoraState->mSerial == theoraState->mSerial)) {
+        continue;
+      }
+
+      if (msgInfo) {
+        InitTrack(msgInfo, &mInfo.mVideo, mTheoraState == theoraState);
+      }
+
+      nsIntRect picture = nsIntRect(theoraState->mInfo.pic_x,
+                                    theoraState->mInfo.pic_y,
+                                    theoraState->mInfo.pic_width,
+                                    theoraState->mInfo.pic_height);
+      nsIntSize displaySize = nsIntSize(theoraState->mInfo.pic_width,
+                                        theoraState->mInfo.pic_height);
+      nsIntSize frameSize(theoraState->mInfo.frame_width,
+                          theoraState->mInfo.frame_height);
+      ScaleDisplayByAspectRatio(displaySize, theoraState->mPixelAspectRatio);
+      if (IsValidVideoRegion(frameSize, picture, displaySize)) {
+        mInfo.mVideo.mDisplay = displaySize;
+      }
+    } else if (codecState->GetType() == OggCodecState::TYPE_VORBIS) {
+      VorbisState* vorbisState = static_cast<VorbisState*>(codecState);
+      if (!(mVorbisState && mVorbisState->mSerial == vorbisState->mSerial)) {
+        continue;
+      }
+
+      if (msgInfo) {
+        InitTrack(msgInfo,
+                  &mInfo.mAudio,
+                  mVorbisState == vorbisState);
+      }
+
+      mInfo.mAudio.mRate = vorbisState->mInfo.rate;
+      mInfo.mAudio.mChannels = vorbisState->mInfo.channels;
+      FillTags(&mInfo.mAudio, vorbisState->GetTags());
+    } else if (codecState->GetType() == OggCodecState::TYPE_OPUS) {
+      OpusState* opusState = static_cast<OpusState*>(codecState);
+      if (!(mOpusState && mOpusState->mSerial == opusState->mSerial)) {
+        continue;
+      }
+
+      if (msgInfo) {
+        InitTrack(msgInfo, &mInfo.mAudio, mOpusState == opusState);
+      }
+
+      mInfo.mAudio.mRate = opusState->mRate;
+      mInfo.mAudio.mChannels = opusState->mChannels;
+      FillTags(&mInfo.mAudio, opusState->GetTags());
+    } else if (codecState->GetType() == OggCodecState::TYPE_FLAC) {
+      FlacState* flacState = static_cast<FlacState*>(codecState);
+      if (!(mFlacState && mFlacState->mSerial == flacState->mSerial)) {
+        continue;
+      }
+
+      if (msgInfo) {
+        InitTrack(msgInfo, &mInfo.mAudio, mFlacState == flacState);
+      }
+
+      mInfo.mAudio = flacState->Info();
+      FillTags(&mInfo.mAudio, flacState->GetTags());
+    }
+  }
+}
+
+void
+OggDemuxer::FillTags(TrackInfo* aInfo, MetadataTags* aTags)
+{
+  if (!aTags) {
+    return;
+  }
+  nsAutoPtr<MetadataTags> tags(aTags);
+  for (auto iter = aTags->Iter(); !iter.Done(); iter.Next()) {
+    aInfo->mTags.AppendElement(MetadataTag(iter.Key(), iter.Data()));
+  }
+}
+
+nsresult
+OggDemuxer::ReadMetadata()
+{
+  OGG_DEBUG("OggDemuxer::ReadMetadata called!");
+
+  // We read packets until all bitstreams have read all their header packets.
+  // We record the offset of the first non-header page so that we know
+  // what page to seek to when seeking to the media start.
+
+  // @FIXME we have to read all the header packets on all the streams
+  // and THEN we can run SetupTarget*
+  // @fixme fixme
+
+  TrackInfo::TrackType tracks[2] =
+    { TrackInfo::kAudioTrack, TrackInfo::kVideoTrack };
+
+  nsTArray<OggCodecState*> bitstreams;
+  nsTArray<uint32_t> serials;
+
+  for (uint32_t i = 0; i < ArrayLength(tracks); i++) {
+    ogg_page page;
+    bool readAllBOS = false;
+    while (!readAllBOS) {
+      if (!ReadOggPage(tracks[i], &page)) {
+        // Some kind of error...
+        OGG_DEBUG("OggDemuxer::ReadOggPage failed? leaving ReadMetadata...");
+        return NS_ERROR_FAILURE;
+      }
+
+      int serial = ogg_page_serialno(&page);
+
+      if (!ogg_page_bos(&page)) {
+        // We've encountered a non Beginning Of Stream page. No more BOS pages
+        // can follow in this Ogg segment, so there will be no other bitstreams
+        // in the Ogg (unless it's invalid).
+        readAllBOS = true;
+      } else if (!mCodecStore.Contains(serial)) {
+        // We've not encountered a stream with this serial number before. Create
+        // an OggCodecState to demux it, and map that to the OggCodecState
+        // in mCodecStates.
+        OggCodecState* codecState = OggCodecState::Create(&page);
+        mCodecStore.Add(serial, codecState);
+        bitstreams.AppendElement(codecState);
+        serials.AppendElement(serial);
+      }
+      if (NS_FAILED(DemuxOggPage(tracks[i], &page))) {
+        return NS_ERROR_FAILURE;
+      }
+    }
+  }
+
+  // We've read all BOS pages, so we know the streams contained in the media.
+  // 1. Find the first encountered Theora/Vorbis/Opus bitstream, and configure
+  //    it as the target A/V bitstream.
+  // 2. Deactivate the rest of bitstreams for now, until we have MediaInfo
+  //    support multiple track infos.
+  for (uint32_t i = 0; i < bitstreams.Length(); ++i) {
+    OggCodecState* s = bitstreams[i];
+    if (s) {
+      OggHeaders headers;
+      if (s->GetType() == OggCodecState::TYPE_THEORA &&
+          ReadHeaders(TrackInfo::kVideoTrack, s, headers)) {
+        if (!mTheoraState) {
+          TheoraState* theoraState = static_cast<TheoraState*>(s);
+          SetupTargetTheora(theoraState, headers);
+        } else {
+          s->Deactivate();
+        }
+      } else if (s->GetType() == OggCodecState::TYPE_VORBIS &&
+                 ReadHeaders(TrackInfo::kAudioTrack, s, headers)) {
+        if (!mVorbisState) {
+          VorbisState* vorbisState = static_cast<VorbisState*>(s);
+          SetupTargetVorbis(vorbisState, headers);
+        } else {
+          s->Deactivate();
+        }
+      } else if (s->GetType() == OggCodecState::TYPE_OPUS &&
+                 ReadHeaders(TrackInfo::kAudioTrack, s, headers)) {
+        if (mOpusEnabled) {
+          if (!mOpusState) {
+            OpusState* opusState = static_cast<OpusState*>(s);
+            SetupTargetOpus(opusState, headers);
+          } else {
+            s->Deactivate();
+          }
+        } else {
+          NS_WARNING("Opus decoding disabled."
+                     " See media.opus.enabled in about:config");
+        }
+      } else if (MediaPrefs::FlacInOgg() &&
+                 s->GetType() == OggCodecState::TYPE_FLAC &&
+                 ReadHeaders(TrackInfo::kAudioTrack, s, headers)) {
+        if (!mFlacState) {
+          FlacState* flacState = static_cast<FlacState*>(s);
+          SetupTargetFlac(flacState, headers);
+        } else {
+          s->Deactivate();
+        }
+      } else if (s->GetType() == OggCodecState::TYPE_SKELETON && !mSkeletonState) {
+        mSkeletonState = static_cast<SkeletonState*>(s);
+      } else {
+        // Deactivate any non-primary bitstreams.
+        s->Deactivate();
+      }
+    }
+  }
+
+  SetupTargetSkeleton();
+  SetupMediaTracksInfo(serials);
+
+  if (HasAudio() || HasVideo()) {
+    int64_t startTime = -1;
+    FindStartTime(startTime);
+    if (startTime >= 0) {
+      OGG_DEBUG("Detected stream start time %lld", startTime);
+      mStartTime.emplace(startTime);
+    }
+
+    if (mInfo.mMetadataDuration.isNothing() &&
+        Resource(TrackInfo::kAudioTrack)->GetLength() >= 0) {
+      // We didn't get a duration from the index or a Content-Duration header.
+      // Seek to the end of file to find the end time.
+      int64_t length = Resource(TrackInfo::kAudioTrack)->GetLength();
+
+      NS_ASSERTION(length > 0, "Must have a content length to get end time");
+
+      int64_t endTime = RangeEndTime(TrackInfo::kAudioTrack, length);
+
+      if (endTime != -1) {
+        mInfo.mUnadjustedMetadataEndTime.emplace(TimeUnit::FromMicroseconds(endTime));
+        mInfo.mMetadataDuration.emplace(TimeUnit::FromMicroseconds(endTime - mStartTime.refOr(0)));
+        OGG_DEBUG("Got Ogg duration from seeking to end %lld", endTime);
+      }
+    }
+    if (mInfo.mMetadataDuration.isNothing()) {
+      mInfo.mMetadataDuration.emplace(TimeUnit::FromInfinity());
+    }
+    if (HasAudio()) {
+      mInfo.mAudio.mDuration = mInfo.mMetadataDuration->ToMicroseconds();
+    }
+    if (HasVideo()) {
+      mInfo.mVideo.mDuration = mInfo.mMetadataDuration->ToMicroseconds();
+    }
+  } else {
+    OGG_DEBUG("no audio or video tracks");
+    return NS_ERROR_FAILURE;
+  }
+
+  OGG_DEBUG("success?!");
+  return NS_OK;
+}
+
+void
+OggDemuxer::SetChained() {
+  {
+    if (mIsChained) {
+      return;
+    }
+    mIsChained = true;
+  }
+  if (mOnSeekableEvent) {
+    mOnSeekableEvent->Notify();
+  }
+}
+
+bool
+OggDemuxer::ReadOggChain(const media::TimeUnit& aLastEndTime)
+{
+  bool chained = false;
+  OpusState* newOpusState = nullptr;
+  VorbisState* newVorbisState = nullptr;
+  FlacState* newFlacState = nullptr;
+  nsAutoPtr<MetadataTags> tags;
+
+  if (HasVideo() || HasSkeleton() || !HasAudio()) {
+    return false;
+  }
+
+  ogg_page page;
+  if (!ReadOggPage(TrackInfo::kAudioTrack, &page) || !ogg_page_bos(&page)) {
+    // Chaining is only supported for audio only ogg files.
+    return false;
+  }
+
+  int serial = ogg_page_serialno(&page);
+  if (mCodecStore.Contains(serial)) {
+    return false;
+  }
+
+  nsAutoPtr<OggCodecState> codecState;
+  codecState = OggCodecState::Create(&page);
+  if (!codecState) {
+    return false;
+  }
+
+  if (mVorbisState && (codecState->GetType() == OggCodecState::TYPE_VORBIS)) {
+    newVorbisState = static_cast<VorbisState*>(codecState.get());
+  } else if (mOpusState && (codecState->GetType() == OggCodecState::TYPE_OPUS)) {
+    newOpusState = static_cast<OpusState*>(codecState.get());
+  } else if (mFlacState && (codecState->GetType() == OggCodecState::TYPE_FLAC)) {
+    newFlacState = static_cast<FlacState*>(codecState.get());
+  } else {
+    return false;
+  }
+
+  OggCodecState* state;
+
+  mCodecStore.Add(serial, codecState.forget());
+  state = mCodecStore.Get(serial);
+
+  NS_ENSURE_TRUE(state != nullptr, false);
+
+  if (NS_FAILED(state->PageIn(&page))) {
+    return false;
+  }
+
+  MessageField* msgInfo = nullptr;
+  if (mSkeletonState && mSkeletonState->mMsgFieldStore.Contains(serial)) {
+    mSkeletonState->mMsgFieldStore.Get(serial, &msgInfo);
+  }
+
+  OggHeaders vorbisHeaders;
+  if ((newVorbisState &&
+       ReadHeaders(TrackInfo::kAudioTrack, newVorbisState, vorbisHeaders)) &&
+      (mVorbisState->mInfo.rate == newVorbisState->mInfo.rate) &&
+      (mVorbisState->mInfo.channels == newVorbisState->mInfo.channels)) {
+
+    SetupTargetVorbis(newVorbisState, vorbisHeaders);
+    LOG(LogLevel::Debug, ("New vorbis ogg link, serial=%d\n", mVorbisSerial));
+
+    if (msgInfo) {
+      InitTrack(msgInfo, &mInfo.mAudio, true);
+    }
+    mInfo.mAudio.mMimeType = NS_LITERAL_CSTRING("audio/vorbis");
+    mInfo.mAudio.mRate = newVorbisState->mInfo.rate;
+    mInfo.mAudio.mChannels = newVorbisState->mInfo.channels;
+
+    chained = true;
+    tags = newVorbisState->GetTags();
+  }
+
+  OggHeaders opusHeaders;
+  if ((newOpusState &&
+       ReadHeaders(TrackInfo::kAudioTrack, newOpusState, opusHeaders)) &&
+      (mOpusState->mRate == newOpusState->mRate) &&
+      (mOpusState->mChannels == newOpusState->mChannels)) {
+
+    SetupTargetOpus(newOpusState, opusHeaders);
+
+    if (msgInfo) {
+      InitTrack(msgInfo, &mInfo.mAudio, true);
+    }
+    mInfo.mAudio.mMimeType = NS_LITERAL_CSTRING("audio/opus");
+    mInfo.mAudio.mRate = newOpusState->mRate;
+    mInfo.mAudio.mChannels = newOpusState->mChannels;
+
+    chained = true;
+    tags = newOpusState->GetTags();
+  }
+
+  OggHeaders flacHeaders;
+  if ((newFlacState &&
+       ReadHeaders(TrackInfo::kAudioTrack, newFlacState, flacHeaders)) &&
+      (mFlacState->Info().mRate == newFlacState->Info().mRate) &&
+      (mFlacState->Info().mChannels == newFlacState->Info().mChannels)) {
+
+    SetupTargetFlac(newFlacState, flacHeaders);
+    LOG(LogLevel::Debug, ("New flac ogg link, serial=%d\n", mFlacSerial));
+
+    if (msgInfo) {
+      InitTrack(msgInfo, &mInfo.mAudio, true);
+    }
+
+    mInfo.mAudio = newFlacState->Info();
+    chained = true;
+    tags = newFlacState->GetTags();
+  }
+
+  if (chained) {
+    SetChained();
+    mInfo.mMediaSeekable = false;
+    mDecodedAudioDuration += aLastEndTime;
+    if (mTimedMetadataEvent) {
+      mTimedMetadataEvent->Notify(
+        TimedMetadata(mDecodedAudioDuration,
+                      Move(tags),
+                      nsAutoPtr<MediaInfo>(new MediaInfo(mInfo))));
+    }
+    // Setup a new TrackInfo so that the MediaFormatReader will flush the
+    // current decoder.
+    mSharedAudioTrackInfo = new SharedTrackInfo(mInfo.mAudio, ++sStreamSourceID);
+    return true;
+  }
+
+  return false;
+}
+
+OggDemuxer::OggStateContext&
+OggDemuxer::OggState(TrackInfo::TrackType aType)
+{
+  if (aType == TrackInfo::kVideoTrack) {
+    return mVideoOggState;
+  }
+  return mAudioOggState;
+}
+
+ogg_sync_state*
+OggDemuxer::OggSyncState(TrackInfo::TrackType aType)
+{
+  return &OggState(aType).mOggState.mState;
+}
+
+MediaResourceIndex*
+OggDemuxer::Resource(TrackInfo::TrackType aType)
+{
+  return &OggState(aType).mResource;
+}
+
+MediaResourceIndex*
+OggDemuxer::CommonResource()
+{
+  return &mAudioOggState.mResource;
+}
+
+bool
+OggDemuxer::ReadOggPage(TrackInfo::TrackType aType, ogg_page* aPage)
+{
+  int ret = 0;
+  while((ret = ogg_sync_pageseek(OggSyncState(aType), aPage)) <= 0) {
+    if (ret < 0) {
+      // Lost page sync, have to skip up to next page.
+      continue;
+    }
+    // Returns a buffer that can be written too
+    // with the given size. This buffer is stored
+    // in the ogg synchronisation structure.
+    char* buffer = ogg_sync_buffer(OggSyncState(aType), 4096);
+    NS_ASSERTION(buffer, "ogg_sync_buffer failed");
+
+    // Read from the resource into the buffer
+    uint32_t bytesRead = 0;
+
+    nsresult rv = Resource(aType)->Read(buffer, 4096, &bytesRead);
+    if (NS_FAILED(rv) || !bytesRead) {
+      // End of file or error.
+      return false;
+    }
+
+    // Update the synchronisation layer with the number
+    // of bytes written to the buffer
+    ret = ogg_sync_wrote(OggSyncState(aType), bytesRead);
+    NS_ENSURE_TRUE(ret == 0, false);
+  }
+
+  return true;
+}
+
+nsresult
+OggDemuxer::DemuxOggPage(TrackInfo::TrackType aType, ogg_page* aPage)
+{
+  int serial = ogg_page_serialno(aPage);
+  OggCodecState* codecState = mCodecStore.Get(serial);
+  if (codecState == nullptr) {
+    OGG_DEBUG("encountered packet for unrecognized codecState");
+    return NS_ERROR_FAILURE;
+  }
+  if (GetCodecStateType(codecState) != aType &&
+      codecState->GetType() != OggCodecState::TYPE_SKELETON) {
+    // Not a page we're interested in.
+    return NS_OK;
+  }
+  if (NS_FAILED(codecState->PageIn(aPage))) {
+    OGG_DEBUG("codecState->PageIn failed");
+    return NS_ERROR_FAILURE;
+  }
+  return NS_OK;
+}
+
+bool
+OggDemuxer::IsSeekable() const
+{
+  if (mIsChained) {
+    return false;
+  }
+  return true;
+}
+
+UniquePtr<EncryptionInfo>
+OggDemuxer::GetCrypto()
+{
+  return nullptr;
+}
+
+ogg_packet*
+OggDemuxer::GetNextPacket(TrackInfo::TrackType aType)
+{
+  OggCodecState* state = GetTrackCodecState(aType);
+  ogg_packet* packet = nullptr;
+  OggStateContext& context = OggState(aType);
+
+  while (true) {
+    if (packet) {
+      OggCodecState::ReleasePacket(state->PacketOut());
+    }
+    DemuxUntilPacketAvailable(aType, state);
+
+    packet = state->PacketPeek();
+    if (!packet) {
+      break;
+    }
+    if (state->IsHeader(packet)) {
+      continue;
+    }
+    if (context.mNeedKeyframe && !state->IsKeyframe(packet)) {
+      continue;
+    }
+    context.mNeedKeyframe = false;
+    break;
+  }
+
+  return packet;
+}
+
+void
+OggDemuxer::DemuxUntilPacketAvailable(TrackInfo::TrackType aType,
+                                      OggCodecState* aState)
+{
+  while (!aState->IsPacketReady()) {
+    OGG_DEBUG("no packet yet, reading some more");
+    ogg_page page;
+    if (!ReadOggPage(aType, &page)) {
+      OGG_DEBUG("no more pages to read in resource?");
+      return;
+    }
+    DemuxOggPage(aType, &page);
+  }
+}
+
+TimeIntervals
+OggDemuxer::GetBuffered(TrackInfo::TrackType aType)
+{
+  if (!HaveStartTime(aType)) {
+    return TimeIntervals();
+  }
+  if (mIsChained) {
+    return TimeIntervals::Invalid();
+  }
+  TimeIntervals buffered;
+  // HasAudio and HasVideo are not used here as they take a lock and cause
+  // a deadlock. Accessing mInfo doesn't require a lock - it doesn't change
+  // after metadata is read.
+  if (!mInfo.HasValidMedia()) {
+    // No need to search through the file if there are no audio or video tracks
+    return buffered;
+  }
+
+  AutoPinned<MediaResource> resource(Resource(aType)->GetResource());
+  MediaByteRangeSet ranges;
+  nsresult res = resource->GetCachedRanges(ranges);
+  NS_ENSURE_SUCCESS(res, TimeIntervals::Invalid());
+
+  // Traverse across the buffered byte ranges, determining the time ranges
+  // they contain. MediaResource::GetNextCachedData(offset) returns -1 when
+  // offset is after the end of the media resource, or there's no more cached
+  // data after the offset. This loop will run until we've checked every
+  // buffered range in the media, in increasing order of offset.
+  nsAutoOggSyncState sync;
+  for (uint32_t index = 0; index < ranges.Length(); index++) {
+    // Ensure the offsets are after the header pages.
+    int64_t startOffset = ranges[index].mStart;
+    int64_t endOffset = ranges[index].mEnd;
+
+    // Because the granulepos time is actually the end time of the page,
+    // we special-case (startOffset == 0) so that the first
+    // buffered range always appears to be buffered from the media start
+    // time, rather than from the end-time of the first page.
+    int64_t startTime = (startOffset == 0) ? StartTime() : -1;
+
+    // Find the start time of the range. Read pages until we find one with a
+    // granulepos which we can convert into a timestamp to use as the time of
+    // the start of the buffered range.
+    ogg_sync_reset(&sync.mState);
+    while (startTime == -1) {
+      ogg_page page;
+      int32_t discard;
+      PageSyncResult pageSyncResult = PageSync(Resource(aType),
+                                               &sync.mState,
+                                               true,
+                                               startOffset,
+                                               endOffset,
+                                               &page,
+                                               discard);
+      if (pageSyncResult == PAGE_SYNC_ERROR) {
+        return TimeIntervals::Invalid();
+      } else if (pageSyncResult == PAGE_SYNC_END_OF_RANGE) {
+        // Hit the end of range without reading a page, give up trying to
+        // find a start time for this buffered range, skip onto the next one.
+        break;
+      }
+
+      int64_t granulepos = ogg_page_granulepos(&page);
+      if (granulepos == -1) {
+        // Page doesn't have an end time, advance to the next page
+        // until we find one.
+        startOffset += page.header_len + page.body_len;
+        continue;
+      }
+
+      uint32_t serial = ogg_page_serialno(&page);
+      if (aType == TrackInfo::kAudioTrack && mVorbisState &&
+          serial == mVorbisSerial) {
+        startTime = VorbisState::Time(&mVorbisInfo, granulepos);
+        NS_ASSERTION(startTime > 0, "Must have positive start time");
+      } else if (aType == TrackInfo::kAudioTrack && mOpusState &&
+                 serial == mOpusSerial) {
+        startTime = OpusState::Time(mOpusPreSkip, granulepos);
+        NS_ASSERTION(startTime > 0, "Must have positive start time");
+      } else if (aType == TrackInfo::kAudioTrack && mFlacState &&
+                 serial == mFlacSerial) {
+        startTime = mFlacState->Time(granulepos);
+        NS_ASSERTION(startTime > 0, "Must have positive start time");
+      } else if (aType == TrackInfo::kVideoTrack && mTheoraState &&
+                 serial == mTheoraSerial) {
+        startTime = TheoraState::Time(&mTheoraInfo, granulepos);
+        NS_ASSERTION(startTime > 0, "Must have positive start time");
+      } else if (mCodecStore.Contains(serial)) {
+        // Stream is not the theora or vorbis stream we're playing,
+        // but is one that we have header data for.
+        startOffset += page.header_len + page.body_len;
+        continue;
+      } else {
+        // Page is for a stream we don't know about (possibly a chained
+        // ogg), return OK to abort the finding any further ranges. This
+        // prevents us searching through the rest of the media when we
+        // may not be able to extract timestamps from it.
+        SetChained();
+        return buffered;
+      }
+    }
+
+    if (startTime != -1) {
+      // We were able to find a start time for that range, see if we can
+      // find an end time.
+      int64_t endTime = RangeEndTime(aType, startOffset, endOffset, true);
+      if (endTime > startTime) {
+        buffered += TimeInterval(
+           TimeUnit::FromMicroseconds(startTime - StartTime()),
+           TimeUnit::FromMicroseconds(endTime - StartTime()));
+      }
+    }
+  }
+
+  return buffered;
+}
+
+void
+OggDemuxer::FindStartTime(int64_t& aOutStartTime)
+{
+  // Extract the start times of the bitstreams in order to calculate
+  // the duration.
+  int64_t videoStartTime = INT64_MAX;
+  int64_t audioStartTime = INT64_MAX;
+
+  if (HasVideo()) {
+    FindStartTime(TrackInfo::kVideoTrack, videoStartTime);
+    if (videoStartTime != INT64_MAX) {
+      OGG_DEBUG("OggDemuxer::FindStartTime() video=%lld", videoStartTime);
+      mVideoOggState.mStartTime =
+        Some(TimeUnit::FromMicroseconds(videoStartTime));
+    }
+  }
+  if (HasAudio()) {
+    FindStartTime(TrackInfo::kAudioTrack, audioStartTime);
+    if (audioStartTime != INT64_MAX) {
+      OGG_DEBUG("OggDemuxer::FindStartTime() audio=%lld", audioStartTime);
+      mAudioOggState.mStartTime =
+        Some(TimeUnit::FromMicroseconds(audioStartTime));
+    }
+  }
+
+  int64_t startTime = std::min(videoStartTime, audioStartTime);
+  if (startTime != INT64_MAX) {
+    aOutStartTime = startTime;
+  }
+}
+
+void
+OggDemuxer::FindStartTime(TrackInfo::TrackType aType, int64_t& aOutStartTime)
+{
+  int64_t startTime = INT64_MAX;
+
+  OggCodecState* state = GetTrackCodecState(aType);
+  ogg_packet* pkt = GetNextPacket(aType);
+  if (pkt) {
+    startTime = state->PacketStartTime(pkt);
+  }
+
+  if (startTime != INT64_MAX) {
+    aOutStartTime = startTime;
+  }
+}
+
+nsresult
+OggDemuxer::SeekInternal(TrackInfo::TrackType aType, const TimeUnit& aTarget)
+{
+  int64_t target = aTarget.ToMicroseconds();
+  OGG_DEBUG("About to seek to %lld", target);
+  nsresult res;
+  int64_t adjustedTarget = target;
+  int64_t startTime = StartTime(aType);
+  int64_t endTime = mInfo.mMetadataDuration->ToMicroseconds();
+  if (aType == TrackInfo::kAudioTrack && mOpusState){
+    adjustedTarget = std::max(startTime, target - OGG_SEEK_OPUS_PREROLL);
+  }
+
+  if (!HaveStartTime(aType) || adjustedTarget == startTime) {
+    // We've seeked to the media start or we can't seek.
+    // Just seek to the offset of the first content page.
+    res = Resource(aType)->Seek(nsISeekableStream::NS_SEEK_SET, 0);
+    NS_ENSURE_SUCCESS(res,res);
+
+    res = Reset(aType);
+    NS_ENSURE_SUCCESS(res,res);
+  } else {
+    // TODO: This may seek back unnecessarily far in the video, but we don't
+    // have a way of asking Skeleton to seek to a different target for each
+    // stream yet. Using adjustedTarget here is at least correct, if slow.
+    IndexedSeekResult sres = SeekToKeyframeUsingIndex(aType, adjustedTarget);
+    NS_ENSURE_TRUE(sres != SEEK_FATAL_ERROR, NS_ERROR_FAILURE);
+    if (sres == SEEK_INDEX_FAIL) {
+      // No index or other non-fatal index-related failure. Try to seek
+      // using a bisection search. Determine the already downloaded data
+      // in the media cache, so we can try to seek in the cached data first.
+      AutoTArray<SeekRange, 16> ranges;
+      res = GetSeekRanges(aType, ranges);
+      NS_ENSURE_SUCCESS(res,res);
+
+      // Figure out if the seek target lies in a buffered range.
+      SeekRange r = SelectSeekRange(aType, ranges, target, startTime, endTime, true);
+
+      if (!r.IsNull()) {
+        // We know the buffered range in which the seek target lies, do a
+        // bisection search in that buffered range.
+        res = SeekInBufferedRange(aType, target, adjustedTarget, startTime, endTime, ranges, r);
+        NS_ENSURE_SUCCESS(res,res);
+      } else {
+        // The target doesn't lie in a buffered range. Perform a bisection
+        // search over the whole media, using the known buffered ranges to
+        // reduce the search space.
+        res = SeekInUnbuffered(aType, target, startTime, endTime, ranges);
+        NS_ENSURE_SUCCESS(res,res);
+      }
+    }
+  }
+
+  // Demux forwards until we find the first keyframe prior the target.
+  // there may be non-keyframes in the page before the keyframe.
+  // Additionally, we may have seeked to the first page referenced by the
+  // page index which may be quite far off the target.
+  // When doing fastSeek we display the first frame after the seek, so
+  // we need to advance the decode to the keyframe otherwise we'll get
+  // visual artifacts in the first frame output after the seek.
+  OggCodecState* state = GetTrackCodecState(aType);
+  OggPacketQueue tempPackets;
+  bool foundKeyframe = false;
+  while (true) {
+    DemuxUntilPacketAvailable(aType, state);
+    ogg_packet* packet = state->PacketPeek();
+    if (packet == nullptr) {
+      OGG_DEBUG("End of stream reached before keyframe found in indexed seek");
+      break;
+    }
+    int64_t startTstamp = state->PacketStartTime(packet);
+    if (foundKeyframe && startTstamp > adjustedTarget) {
+      break;
+    }
+    if (state->IsKeyframe(packet)) {
+      OGG_DEBUG("keyframe found after seeking at %lld", startTstamp);
+      tempPackets.Erase();
+      foundKeyframe = true;
+    }
+    if (foundKeyframe && startTstamp == adjustedTarget) {
+      break;
+    }
+    ogg_packet* releaseMe = state->PacketOut();
+    if (foundKeyframe) {
+      tempPackets.Append(releaseMe);
+    } else {
+      // Discard video packets before the first keyframe.
+      OggCodecState::ReleasePacket(releaseMe);
+    }
+  }
+  // Re-add all packet into the codec state in order.
+  state->PushFront(Move(tempPackets));
+
+  return NS_OK;
+}
+
+OggDemuxer::IndexedSeekResult
+OggDemuxer::RollbackIndexedSeek(TrackInfo::TrackType aType, int64_t aOffset)
+{
+  if (mSkeletonState) {
+    mSkeletonState->Deactivate();
+  }
+  nsresult res = Resource(aType)->Seek(nsISeekableStream::NS_SEEK_SET, aOffset);
+  NS_ENSURE_SUCCESS(res, SEEK_FATAL_ERROR);
+  return SEEK_INDEX_FAIL;
+}
+
+OggDemuxer::IndexedSeekResult
+OggDemuxer::SeekToKeyframeUsingIndex(TrackInfo::TrackType aType, int64_t aTarget)
+{
+  if (!HasSkeleton() || !mSkeletonState->HasIndex()) {
+    return SEEK_INDEX_FAIL;
+  }
+  // We have an index from the Skeleton track, try to use it to seek.
+  AutoTArray<uint32_t, 2> tracks;
+  BuildSerialList(tracks);
+  SkeletonState::nsSeekTarget keyframe;
+  if (NS_FAILED(mSkeletonState->IndexedSeekTarget(aTarget,
+                                                  tracks,
+                                                  keyframe))) {
+    // Could not locate a keypoint for the target in the index.
+    return SEEK_INDEX_FAIL;
+  }
+
+  // Remember original resource read cursor position so we can rollback on failure.
+  int64_t tell = Resource(aType)->Tell();
+
+  // Seek to the keypoint returned by the index.
+  if (keyframe.mKeyPoint.mOffset > Resource(aType)->GetLength() ||
+      keyframe.mKeyPoint.mOffset < 0) {
+    // Index must be invalid.
+    return RollbackIndexedSeek(aType, tell);
+  }
+  LOG(LogLevel::Debug, ("Seeking using index to keyframe at offset %lld\n",
+                     keyframe.mKeyPoint.mOffset));
+  nsresult res = Resource(aType)->Seek(nsISeekableStream::NS_SEEK_SET,
+                                       keyframe.mKeyPoint.mOffset);
+  NS_ENSURE_SUCCESS(res, SEEK_FATAL_ERROR);
+
+  // We've moved the read set, so reset decode.
+  res = Reset(aType);
+  NS_ENSURE_SUCCESS(res, SEEK_FATAL_ERROR);
+
+  // Check that the page the index thinks is exactly here is actually exactly
+  // here. If not, the index is invalid.
+  ogg_page page;
+  int skippedBytes = 0;
+  PageSyncResult syncres = PageSync(Resource(aType),
+                                    OggSyncState(aType),
+                                    false,
+                                    keyframe.mKeyPoint.mOffset,
+                                    Resource(aType)->GetLength(),
+                                    &page,
+                                    skippedBytes);
+  NS_ENSURE_TRUE(syncres != PAGE_SYNC_ERROR, SEEK_FATAL_ERROR);
+  if (syncres != PAGE_SYNC_OK || skippedBytes != 0) {
+    LOG(LogLevel::Debug, ("Indexed-seek failure: Ogg Skeleton Index is invalid "
+                       "or sync error after seek"));
+    return RollbackIndexedSeek(aType, tell);
+  }
+  uint32_t serial = ogg_page_serialno(&page);
+  if (serial != keyframe.mSerial) {
+    // Serialno of page at offset isn't what the index told us to expect.
+    // Assume the index is invalid.
+    return RollbackIndexedSeek(aType, tell);
+  }
+  OggCodecState* codecState = mCodecStore.Get(serial);
+  if (codecState && codecState->mActive &&
+      ogg_stream_pagein(&codecState->mState, &page) != 0) {
+    // Couldn't insert page into the ogg resource, or somehow the resource
+    // is no longer active.
+    return RollbackIndexedSeek(aType, tell);
+  }
+  return SEEK_OK;
+}
+
+// Reads a page from the media resource.
+OggDemuxer::PageSyncResult
+OggDemuxer::PageSync(MediaResourceIndex* aResource,
+                     ogg_sync_state* aState,
+                     bool aCachedDataOnly,
+                     int64_t aOffset,
+                     int64_t aEndOffset,
+                     ogg_page* aPage,
+                     int& aSkippedBytes)
+{
+  aSkippedBytes = 0;
+  // Sync to the next page.
+  int ret = 0;
+  uint32_t bytesRead = 0;
+  int64_t readHead = aOffset;
+  while (ret <= 0) {
+    ret = ogg_sync_pageseek(aState, aPage);
+    if (ret == 0) {
+      char* buffer = ogg_sync_buffer(aState, PAGE_STEP);
+      NS_ASSERTION(buffer, "Must have a buffer");
+
+      // Read from the file into the buffer
+      int64_t bytesToRead = std::min(static_cast<int64_t>(PAGE_STEP),
+                                   aEndOffset - readHead);
+      NS_ASSERTION(bytesToRead <= UINT32_MAX, "bytesToRead range check");
+      if (bytesToRead <= 0) {
+        return PAGE_SYNC_END_OF_RANGE;
+      }
+      nsresult rv = NS_OK;
+      if (aCachedDataOnly) {
+        rv = aResource->GetResource()->ReadFromCache(buffer, readHead,
+                                                     static_cast<uint32_t>(bytesToRead));
+        NS_ENSURE_SUCCESS(rv,PAGE_SYNC_ERROR);
+        bytesRead = static_cast<uint32_t>(bytesToRead);
+      } else {
+        rv = aResource->Seek(nsISeekableStream::NS_SEEK_SET, readHead);
+        NS_ENSURE_SUCCESS(rv,PAGE_SYNC_ERROR);
+        rv = aResource->Read(buffer,
+                             static_cast<uint32_t>(bytesToRead),
+                             &bytesRead);
+        NS_ENSURE_SUCCESS(rv,PAGE_SYNC_ERROR);
+      }
+      if (bytesRead == 0 && NS_SUCCEEDED(rv)) {
+        // End of file.
+        return PAGE_SYNC_END_OF_RANGE;
+      }
+      readHead += bytesRead;
+
+      // Update the synchronisation layer with the number
+      // of bytes written to the buffer
+      ret = ogg_sync_wrote(aState, bytesRead);
+      NS_ENSURE_TRUE(ret == 0, PAGE_SYNC_ERROR);
+      continue;
+    }
+
+    if (ret < 0) {
+      NS_ASSERTION(aSkippedBytes >= 0, "Offset >= 0");
+      aSkippedBytes += -ret;
+      NS_ASSERTION(aSkippedBytes >= 0, "Offset >= 0");
+      continue;
+    }
+  }
+
+  return PAGE_SYNC_OK;
+}
+
+//OggTrackDemuxer
+OggTrackDemuxer::OggTrackDemuxer(OggDemuxer* aParent,
+                                 TrackInfo::TrackType aType,
+                                 uint32_t aTrackNumber)
+  : mParent(aParent)
+  , mType(aType)
+{
+  mInfo = mParent->GetTrackInfo(aType, aTrackNumber);
+  MOZ_ASSERT(mInfo);
+}
+
+OggTrackDemuxer::~OggTrackDemuxer()
+{
+}
+
+UniquePtr<TrackInfo>
+OggTrackDemuxer::GetInfo() const
+{
+  return mInfo->Clone();
+}
+
+RefPtr<OggTrackDemuxer::SeekPromise>
+OggTrackDemuxer::Seek(TimeUnit aTime)
+{
+  // Seeks to aTime. Upon success, SeekPromise will be resolved with the
+  // actual time seeked to. Typically the random access point time
+  mQueuedSample = nullptr;
+  TimeUnit seekTime = aTime;
+  if (mParent->SeekInternal(mType, aTime) == NS_OK) {
+    RefPtr<MediaRawData> sample(NextSample());
+
+    // Check what time we actually seeked to.
+    if (sample != nullptr) {
+      seekTime = TimeUnit::FromMicroseconds(sample->mTime);
+      OGG_DEBUG("%p seeked to time %lld", this, seekTime.ToMicroseconds());
+    }
+    mQueuedSample = sample;
+
+    return SeekPromise::CreateAndResolve(seekTime, __func__);
+  } else {
+    return SeekPromise::CreateAndReject(NS_ERROR_DOM_MEDIA_DEMUXER_ERR, __func__);
+  }
+}
+
+RefPtr<MediaRawData>
+OggTrackDemuxer::NextSample()
+{
+  if (mQueuedSample) {
+    RefPtr<MediaRawData> nextSample = mQueuedSample;
+    mQueuedSample = nullptr;
+    if (mType == TrackInfo::kAudioTrack) {
+      nextSample->mTrackInfo = mParent->mSharedAudioTrackInfo;
+    }
+    return nextSample;
+  }
+  ogg_packet* packet = mParent->GetNextPacket(mType);
+  if (!packet) {
+    return nullptr;
+  }
+  // Check the eos state in case we need to look for chained streams.
+  bool eos = packet->e_o_s;
+  OggCodecState* state = mParent->GetTrackCodecState(mType);
+  RefPtr<MediaRawData> data = state->PacketOutAsMediaRawData();
+  if (!data) {
+    return nullptr;
+  }
+  if (mType == TrackInfo::kAudioTrack) {
+    data->mTrackInfo = mParent->mSharedAudioTrackInfo;
+  }
+  if (eos) {
+    // We've encountered an end of bitstream packet; check for a chained
+    // bitstream following this one.
+    // This will also update mSharedAudioTrackInfo.
+    mParent->ReadOggChain(TimeUnit::FromMicroseconds(data->GetEndTime()));
+  }
+  return data;
+}
+
+RefPtr<OggTrackDemuxer::SamplesPromise>
+OggTrackDemuxer::GetSamples(int32_t aNumSamples)
+{
+  RefPtr<SamplesHolder> samples = new SamplesHolder;
+  if (!aNumSamples) {
+    return SamplesPromise::CreateAndReject(NS_ERROR_DOM_MEDIA_DEMUXER_ERR, __func__);
+  }
+
+  while (aNumSamples) {
+    RefPtr<MediaRawData> sample(NextSample());
+    if (!sample) {
+      break;
+    }
+    samples->mSamples.AppendElement(sample);
+    aNumSamples--;
+  }
+
+  if (samples->mSamples.IsEmpty()) {
+    return SamplesPromise::CreateAndReject(NS_ERROR_DOM_MEDIA_END_OF_STREAM, __func__);
+  } else {
+    return SamplesPromise::CreateAndResolve(samples, __func__);
+  }
+}
+
+void
+OggTrackDemuxer::Reset()
+{
+  mParent->Reset(mType);
+  mQueuedSample = nullptr;
+}
+
+RefPtr<OggTrackDemuxer::SkipAccessPointPromise>
+OggTrackDemuxer::SkipToNextRandomAccessPoint(TimeUnit aTimeThreshold)
+{
+  uint32_t parsed = 0;
+  bool found = false;
+  RefPtr<MediaRawData> sample;
+
+  OGG_DEBUG("TimeThreshold: %f", aTimeThreshold.ToSeconds());
+  while (!found && (sample = NextSample())) {
+    parsed++;
+    if (sample->mKeyframe && sample->mTime >= aTimeThreshold.ToMicroseconds()) {
+      found = true;
+      mQueuedSample = sample;
+    }
+  }
+  if (found) {
+    OGG_DEBUG("next sample: %f (parsed: %d)",
+               TimeUnit::FromMicroseconds(sample->mTime).ToSeconds(),
+               parsed);
+    return SkipAccessPointPromise::CreateAndResolve(parsed, __func__);
+  } else {
+    SkipFailureHolder failure(NS_ERROR_DOM_MEDIA_END_OF_STREAM, parsed);
+    return SkipAccessPointPromise::CreateAndReject(Move(failure), __func__);
+  }
+}
+
+TimeIntervals
+OggTrackDemuxer::GetBuffered()
+{
+  return mParent->GetBuffered(mType);
+}
+
+void
+OggTrackDemuxer::BreakCycles()
+{
+  mParent = nullptr;
+}
+
+
+// Returns an ogg page's checksum.
+ogg_uint32_t
+OggDemuxer::GetPageChecksum(ogg_page* page)
+{
+  if (page == 0 || page->header == 0 || page->header_len < 25) {
+    return 0;
+  }
+  const unsigned char* p = page->header + 22;
+  uint32_t c = p[0] + (p[1] << 8) + (p[2] << 16) + (p[3] << 24);
+  return c;
+}
+
+int64_t
+OggDemuxer::RangeStartTime(TrackInfo::TrackType aType, int64_t aOffset)
+{
+  int64_t position = Resource(aType)->Tell();
+  nsresult res = Resource(aType)->Seek(nsISeekableStream::NS_SEEK_SET, aOffset);
+  NS_ENSURE_SUCCESS(res, 0);
+  int64_t startTime = 0;
+  FindStartTime(aType, startTime);
+  res = Resource(aType)->Seek(nsISeekableStream::NS_SEEK_SET, position);
+  NS_ENSURE_SUCCESS(res, -1);
+  return startTime;
+}
+
+struct nsDemuxerAutoOggSyncState
+{
+  nsDemuxerAutoOggSyncState()
+  {
+    ogg_sync_init(&mState);
+  }
+  ~nsDemuxerAutoOggSyncState()
+  {
+    ogg_sync_clear(&mState);
+  }
+  ogg_sync_state mState;
+};
+
+int64_t
+OggDemuxer::RangeEndTime(TrackInfo::TrackType aType, int64_t aEndOffset)
+{
+  int64_t position = Resource(aType)->Tell();
+  int64_t endTime = RangeEndTime(aType, 0, aEndOffset, false);
+  nsresult res = Resource(aType)->Seek(nsISeekableStream::NS_SEEK_SET, position);
+  NS_ENSURE_SUCCESS(res, -1);
+  return endTime;
+}
+
+int64_t
+OggDemuxer::RangeEndTime(TrackInfo::TrackType aType,
+                         int64_t aStartOffset,
+                         int64_t aEndOffset,
+                         bool aCachedDataOnly)
+{
+  nsDemuxerAutoOggSyncState sync;
+
+  // We need to find the last page which ends before aEndOffset that
+  // has a granulepos that we can convert to a timestamp. We do this by
+  // backing off from aEndOffset until we encounter a page on which we can
+  // interpret the granulepos. If while backing off we encounter a page which
+  // we've previously encountered before, we'll either backoff again if we
+  // haven't found an end time yet, or return the last end time found.
+  const int step = 5000;
+  const int maxOggPageSize = 65306;
+  int64_t readStartOffset = aEndOffset;
+  int64_t readLimitOffset = aEndOffset;
+  int64_t readHead = aEndOffset;
+  int64_t endTime = -1;
+  uint32_t checksumAfterSeek = 0;
+  uint32_t prevChecksumAfterSeek = 0;
+  bool mustBackOff = false;
+  while (true) {
+    ogg_page page;
+    int ret = ogg_sync_pageseek(&sync.mState, &page);
+    if (ret == 0) {
+      // We need more data if we've not encountered a page we've seen before,
+      // or we've read to the end of file.
+      if (mustBackOff || readHead == aEndOffset || readHead == aStartOffset) {
+        if (endTime != -1 || readStartOffset == 0) {
+          // We have encountered a page before, or we're at the end of file.
+          break;
+        }
+        mustBackOff = false;
+        prevChecksumAfterSeek = checksumAfterSeek;
+        checksumAfterSeek = 0;
+        ogg_sync_reset(&sync.mState);
+        readStartOffset = std::max(static_cast<int64_t>(0), readStartOffset - step);
+        // There's no point reading more than the maximum size of
+        // an Ogg page into data we've previously scanned. Any data
+        // between readLimitOffset and aEndOffset must be garbage
+        // and we can ignore it thereafter.
+        readLimitOffset = std::min(readLimitOffset,
+                                   readStartOffset + maxOggPageSize);
+        readHead = std::max(aStartOffset, readStartOffset);
+      }
+
+      int64_t limit = std::min(static_cast<int64_t>(UINT32_MAX),
+                               aEndOffset - readHead);
+      limit = std::max(static_cast<int64_t>(0), limit);
+      limit = std::min(limit, static_cast<int64_t>(step));
+      uint32_t bytesToRead = static_cast<uint32_t>(limit);
+      uint32_t bytesRead = 0;
+      char* buffer = ogg_sync_buffer(&sync.mState, bytesToRead);
+      NS_ASSERTION(buffer, "Must have buffer");
+      nsresult res;
+      if (aCachedDataOnly) {
+        res = Resource(aType)->GetResource()->ReadFromCache(buffer, readHead, bytesToRead);
+        NS_ENSURE_SUCCESS(res, -1);
+        bytesRead = bytesToRead;
+      } else {
+        NS_ASSERTION(readHead < aEndOffset,
+                     "resource pos must be before range end");
+        res = Resource(aType)->Seek(nsISeekableStream::NS_SEEK_SET, readHead);
+        NS_ENSURE_SUCCESS(res, -1);
+        res = Resource(aType)->Read(buffer, bytesToRead, &bytesRead);
+        NS_ENSURE_SUCCESS(res, -1);
+      }
+      readHead += bytesRead;
+      if (readHead > readLimitOffset) {
+        mustBackOff = true;
+      }
+
+      // Update the synchronisation layer with the number
+      // of bytes written to the buffer
+      ret = ogg_sync_wrote(&sync.mState, bytesRead);
+      if (ret != 0) {
+        endTime = -1;
+        break;
+      }
+      continue;
+    }
+
+    if (ret < 0 || ogg_page_granulepos(&page) < 0) {
+      continue;
+    }
+
+    uint32_t checksum = GetPageChecksum(&page);
+    if (checksumAfterSeek == 0) {
+      // This is the first page we've decoded after a backoff/seek. Remember
+      // the page checksum. If we backoff further and encounter this page
+      // again, we'll know that we won't find a page with an end time after
+      // this one, so we'll know to back off again.
+      checksumAfterSeek = checksum;
+    }
+    if (checksum == prevChecksumAfterSeek) {
+      // This page has the same checksum as the first page we encountered
+      // after the last backoff/seek. Since we've already scanned after this
+      // page and failed to find an end time, we may as well backoff again and
+      // try to find an end time from an earlier page.
+      mustBackOff = true;
+      continue;
+    }
+
+    int64_t granulepos = ogg_page_granulepos(&page);
+    int serial = ogg_page_serialno(&page);
+
+    OggCodecState* codecState = nullptr;
+    codecState = mCodecStore.Get(serial);
+    if (!codecState) {
+      // This page is from a bitstream which we haven't encountered yet.
+      // It's probably from a new "link" in a "chained" ogg. Don't
+      // bother even trying to find a duration...
+      SetChained();
+      endTime = -1;
+      break;
+    }
+
+    int64_t t = codecState->Time(granulepos);
+    if (t != -1) {
+      endTime = t;
+    }
+  }
+
+  return endTime;
+}
+
+nsresult
+OggDemuxer::GetSeekRanges(TrackInfo::TrackType aType,
+                          nsTArray<SeekRange>& aRanges)
+{
+  AutoPinned<MediaResource> resource(Resource(aType)->GetResource());
+  MediaByteRangeSet cached;
+  nsresult res = resource->GetCachedRanges(cached);
+  NS_ENSURE_SUCCESS(res, res);
+
+  for (uint32_t index = 0; index < cached.Length(); index++) {
+    auto& range = cached[index];
+    int64_t startTime = -1;
+    int64_t endTime = -1;
+    if (NS_FAILED(Reset(aType))) {
+      return NS_ERROR_FAILURE;
+    }
+    int64_t startOffset = range.mStart;
+    int64_t endOffset = range.mEnd;
+    startTime = RangeStartTime(aType, startOffset);
+    if (startTime != -1 &&
+        ((endTime = RangeEndTime(aType, endOffset)) != -1)) {
+      NS_WARNING_ASSERTION(startTime < endTime,
+                           "Start time must be before end time");
+      aRanges.AppendElement(SeekRange(startOffset,
+                                      endOffset,
+                                      startTime,
+                                      endTime));
+     }
+  }
+  if (NS_FAILED(Reset(aType))) {
+    return NS_ERROR_FAILURE;
+  }
+  return NS_OK;
+}
+
+OggDemuxer::SeekRange
+OggDemuxer::SelectSeekRange(TrackInfo::TrackType aType,
+                            const nsTArray<SeekRange>& ranges,
+                            int64_t aTarget,
+                            int64_t aStartTime,
+                            int64_t aEndTime,
+                            bool aExact)
+{
+  int64_t so = 0;
+  int64_t eo = Resource(aType)->GetLength();
+  int64_t st = aStartTime;
+  int64_t et = aEndTime;
+  for (uint32_t i = 0; i < ranges.Length(); i++) {
+    const SeekRange& r = ranges[i];
+    if (r.mTimeStart < aTarget) {
+      so = r.mOffsetStart;
+      st = r.mTimeStart;
+    }
+    if (r.mTimeEnd >= aTarget && r.mTimeEnd < et) {
+      eo = r.mOffsetEnd;
+      et = r.mTimeEnd;
+    }
+
+    if (r.mTimeStart < aTarget && aTarget <= r.mTimeEnd) {
+      // Target lies exactly in this range.
+      return ranges[i];
+    }
+  }
+  if (aExact || eo == -1) {
+    return SeekRange();
+  }
+  return SeekRange(so, eo, st, et);
+}
+
+
+nsresult
+OggDemuxer::SeekInBufferedRange(TrackInfo::TrackType aType,
+                                int64_t aTarget,
+                                int64_t aAdjustedTarget,
+                                int64_t aStartTime,
+                                int64_t aEndTime,
+                                const nsTArray<SeekRange>& aRanges,
+                                const SeekRange& aRange)
+{
+  OGG_DEBUG("Seeking in buffered data to %lld using bisection search", aTarget);
+  if (aType == TrackInfo::kVideoTrack || aAdjustedTarget >= aTarget) {
+    // We know the exact byte range in which the target must lie. It must
+    // be buffered in the media cache. Seek there.
+    nsresult res = SeekBisection(aType, aTarget, aRange, 0);
+    if (NS_FAILED(res) || aType != TrackInfo::kVideoTrack) {
+      return res;
+    }
+
+    // We have an active Theora bitstream. Peek the next Theora frame, and
+    // extract its keyframe's time.
+    DemuxUntilPacketAvailable(aType, mTheoraState);
+    ogg_packet* packet = mTheoraState->PacketPeek();
+    if (packet && !mTheoraState->IsKeyframe(packet)) {
+      // First post-seek frame isn't a keyframe, seek back to previous keyframe,
+      // otherwise we'll get visual artifacts.
+      NS_ASSERTION(packet->granulepos != -1, "Must have a granulepos");
+      int shift = mTheoraState->mInfo.keyframe_granule_shift;
+      int64_t keyframeGranulepos = (packet->granulepos >> shift) << shift;
+      int64_t keyframeTime = mTheoraState->StartTime(keyframeGranulepos);
+      SEEK_LOG(LogLevel::Debug, ("Keyframe for %lld is at %lld, seeking back to it",
+                              frameTime, keyframeTime));
+      aAdjustedTarget = std::min(aAdjustedTarget, keyframeTime);
+    }
+  }
+
+  nsresult res = NS_OK;
+  if (aAdjustedTarget < aTarget) {
+    SeekRange k = SelectSeekRange(aType,
+                                  aRanges,
+                                  aAdjustedTarget,
+                                  aStartTime,
+                                  aEndTime,
+                                  false);
+    res = SeekBisection(aType, aAdjustedTarget, k, OGG_SEEK_FUZZ_USECS);
+  }
+  return res;
+}
+
+nsresult
+OggDemuxer::SeekInUnbuffered(TrackInfo::TrackType aType,
+                             int64_t aTarget,
+                             int64_t aStartTime,
+                             int64_t aEndTime,
+                             const nsTArray<SeekRange>& aRanges)
+{
+  OGG_DEBUG("Seeking in unbuffered data to %lld using bisection search", aTarget);
+
+  // If we've got an active Theora bitstream, determine the maximum possible
+  // time in usecs which a keyframe could be before a given interframe. We
+  // subtract this from our seek target, seek to the new target, and then
+  // will decode forward to the original seek target. We should encounter a
+  // keyframe in that interval. This prevents us from needing to run two
+  // bisections; one for the seek target frame, and another to find its
+  // keyframe. It's usually faster to just download this extra data, rather
+  // tham perform two bisections to find the seek target's keyframe. We
+  // don't do this offsetting when seeking in a buffered range,
+  // as the extra decoding causes a noticeable speed hit when all the data
+  // is buffered (compared to just doing a bisection to exactly find the
+  // keyframe).
+  int64_t keyframeOffsetMs = 0;
+  if (aType == TrackInfo::kVideoTrack && mTheoraState) {
+    keyframeOffsetMs = mTheoraState->MaxKeyframeOffset();
+  }
+  // Add in the Opus pre-roll if necessary, as well.
+  if (aType == TrackInfo::kAudioTrack && mOpusState) {
+    keyframeOffsetMs = std::max(keyframeOffsetMs, OGG_SEEK_OPUS_PREROLL);
+  }
+  int64_t seekTarget = std::max(aStartTime, aTarget - keyframeOffsetMs);
+  // Minimize the bisection search space using the known timestamps from the
+  // buffered ranges.
+  SeekRange k =
+    SelectSeekRange(aType, aRanges, seekTarget, aStartTime, aEndTime, false);
+  return SeekBisection(aType, seekTarget, k, OGG_SEEK_FUZZ_USECS);
+}
+
+nsresult
+OggDemuxer::SeekBisection(TrackInfo::TrackType aType,
+                          int64_t aTarget,
+                          const SeekRange& aRange,
+                          uint32_t aFuzz)
+{
+  nsresult res;
+
+  if (aTarget <= aRange.mTimeStart) {
+    if (NS_FAILED(Reset(aType))) {
+      return NS_ERROR_FAILURE;
+    }
+    res = Resource(aType)->Seek(nsISeekableStream::NS_SEEK_SET, 0);
+    NS_ENSURE_SUCCESS(res,res);
+    return NS_OK;
+  }
+
+  // Bisection search, find start offset of last page with end time less than
+  // the seek target.
+  ogg_int64_t startOffset = aRange.mOffsetStart;
+  ogg_int64_t startTime = aRange.mTimeStart;
+  ogg_int64_t startLength = 0; // Length of the page at startOffset.
+  ogg_int64_t endOffset = aRange.mOffsetEnd;
+  ogg_int64_t endTime = aRange.mTimeEnd;
+
+  ogg_int64_t seekTarget = aTarget;
+  int64_t seekLowerBound = std::max(static_cast<int64_t>(0), aTarget - aFuzz);
+  int hops = 0;
+  DebugOnly<ogg_int64_t> previousGuess = -1;
+  int backsteps = 0;
+  const int maxBackStep = 10;
+  NS_ASSERTION(static_cast<uint64_t>(PAGE_STEP) * pow(2.0, maxBackStep) < INT32_MAX,
+               "Backstep calculation must not overflow");
+
+  // Seek via bisection search. Loop until we find the offset where the page
+  // before the offset is before the seek target, and the page after the offset
+  // is after the seek target.
+  while (true) {
+    ogg_int64_t duration = 0;
+    double target = 0;
+    ogg_int64_t interval = 0;
+    ogg_int64_t guess = 0;
+    ogg_page page;
+    int skippedBytes = 0;
+    ogg_int64_t pageOffset = 0;
+    ogg_int64_t pageLength = 0;
+    ogg_int64_t granuleTime = -1;
+    bool mustBackoff = false;
+
+    // Guess where we should bisect to, based on the bit rate and the time
+    // remaining in the interval. Loop until we can determine the time at
+    // the guess offset.
+    while (true) {
+
+      // Discard any previously buffered packets/pages.
+      if (NS_FAILED(Reset(aType))) {
+        return NS_ERROR_FAILURE;
+      }
+
+      interval = endOffset - startOffset - startLength;
+      if (interval == 0) {
+        // Our interval is empty, we've found the optimal seek point, as the
+        // page at the start offset is before the seek target, and the page
+        // at the end offset is after the seek target.
+        SEEK_LOG(LogLevel::Debug, ("Interval narrowed, terminating bisection."));
+        break;
+      }
+
+      // Guess bisection point.
+      duration = endTime - startTime;
+      target = (double)(seekTarget - startTime) / (double)duration;
+      guess = startOffset + startLength +
+              static_cast<ogg_int64_t>((double)interval * target);
+      guess = std::min(guess, endOffset - PAGE_STEP);
+      if (mustBackoff) {
+        // We previously failed to determine the time at the guess offset,
+        // probably because we ran out of data to decode. This usually happens
+        // when we guess very close to the end offset. So reduce the guess
+        // offset using an exponential backoff until we determine the time.
+        SEEK_LOG(LogLevel::Debug, ("Backing off %d bytes, backsteps=%d",
+          static_cast<int32_t>(PAGE_STEP * pow(2.0, backsteps)), backsteps));
+        guess -= PAGE_STEP * static_cast<ogg_int64_t>(pow(2.0, backsteps));
+
+        if (guess <= startOffset) {
+          // We've tried to backoff to before the start offset of our seek
+          // range. This means we couldn't find a seek termination position
+          // near the end of the seek range, so just set the seek termination
+          // condition, and break out of the bisection loop. We'll begin
+          // decoding from the start of the seek range.
+          interval = 0;
+          break;
+        }
+
+        backsteps = std::min(backsteps + 1, maxBackStep);
+        // We reset mustBackoff. If we still need to backoff further, it will
+        // be set to true again.
+        mustBackoff = false;
+      } else {
+        backsteps = 0;
+      }
+      guess = std::max(guess, startOffset + startLength);
+
+      SEEK_LOG(LogLevel::Debug, ("Seek loop start[o=%lld..%lld t=%lld] "
+                              "end[o=%lld t=%lld] "
+                              "interval=%lld target=%lf guess=%lld",
+                              startOffset, (startOffset+startLength), startTime,
+                              endOffset, endTime, interval, target, guess));
+
+      NS_ASSERTION(guess >= startOffset + startLength, "Guess must be after range start");
+      NS_ASSERTION(guess < endOffset, "Guess must be before range end");
+      NS_ASSERTION(guess != previousGuess, "Guess should be different to previous");
+      previousGuess = guess;
+
+      hops++;
+
+      // Locate the next page after our seek guess, and then figure out the
+      // granule time of the audio and video bitstreams there. We can then
+      // make a bisection decision based on our location in the media.
+      PageSyncResult pageSyncResult = PageSync(Resource(aType),
+                                               OggSyncState(aType),
+                                               false,
+                                               guess,
+                                               endOffset,
+                                               &page,
+                                               skippedBytes);
+      NS_ENSURE_TRUE(pageSyncResult != PAGE_SYNC_ERROR, NS_ERROR_FAILURE);
+
+      if (pageSyncResult == PAGE_SYNC_END_OF_RANGE) {
+        // Our guess was too close to the end, we've ended up reading the end
+        // page. Backoff exponentially from the end point, in case the last
+        // page/frame/sample is huge.
+        mustBackoff = true;
+        SEEK_LOG(LogLevel::Debug, ("Hit the end of range, backing off"));
+        continue;
+      }
+
+      // We've located a page of length |ret| at |guess + skippedBytes|.
+      // Remember where the page is located.
+      pageOffset = guess + skippedBytes;
+      pageLength = page.header_len + page.body_len;
+
+      // Read pages until we can determine the granule time of the audio and
+      // video bitstream.
+      ogg_int64_t audioTime = -1;
+      ogg_int64_t videoTime = -1;
+      do {
+        // Add the page to its codec state, determine its granule time.
+        uint32_t serial = ogg_page_serialno(&page);
+        OggCodecState* codecState = mCodecStore.Get(serial);
+        if (codecState && GetCodecStateType(codecState) == aType) {
+          if (codecState->mActive) {
+            int ret = ogg_stream_pagein(&codecState->mState, &page);
+            NS_ENSURE_TRUE(ret == 0, NS_ERROR_FAILURE);
+          }
+
+          ogg_int64_t granulepos = ogg_page_granulepos(&page);
+
+          if (aType == TrackInfo::kAudioTrack &&
+              granulepos > 0 && audioTime == -1) {
+            if (mVorbisState && serial == mVorbisState->mSerial) {
+              audioTime = mVorbisState->Time(granulepos);
+            } else if (mOpusState && serial == mOpusState->mSerial) {
+              audioTime = mOpusState->Time(granulepos);
+            } else if (mFlacState && serial == mFlacState->mSerial) {
+              audioTime = mFlacState->Time(granulepos);
+            }
+          }
+
+          if (aType == TrackInfo::kVideoTrack &&
+              granulepos > 0 && serial == mTheoraState->mSerial &&
+              videoTime == -1) {
+            videoTime = mTheoraState->Time(granulepos);
+          }
+
+          if (pageOffset + pageLength >= endOffset) {
+            // Hit end of readable data.
+            break;
+          }
+        }
+        if (!ReadOggPage(aType, &page)) {
+          break;
+        }
+
+      } while ((aType == TrackInfo::kAudioTrack && audioTime == -1) ||
+               (aType == TrackInfo::kVideoTrack && videoTime == -1));
+
+
+      if ((aType == TrackInfo::kAudioTrack && audioTime == -1) ||
+          (aType == TrackInfo::kVideoTrack && videoTime == -1)) {
+        // We don't have timestamps for all active tracks...
+        if (pageOffset == startOffset + startLength &&
+            pageOffset + pageLength >= endOffset) {
+          // We read the entire interval without finding timestamps for all
+          // active tracks. We know the interval start offset is before the seek
+          // target, and the interval end is after the seek target, and we can't
+          // terminate inside the interval, so we terminate the seek at the
+          // start of the interval.
+          interval = 0;
+          break;
+        }
+
+        // We should backoff; cause the guess to back off from the end, so
+        // that we've got more room to capture.
+        mustBackoff = true;
+        continue;
+      }
+
+      // We've found appropriate time stamps here. Proceed to bisect
+      // the search space.
+      granuleTime = aType == TrackInfo::kAudioTrack ? audioTime : videoTime;
+      NS_ASSERTION(granuleTime > 0, "Must get a granuletime");
+      break;
+    } // End of "until we determine time at guess offset" loop.
+
+    if (interval == 0) {
+      // Seek termination condition; we've found the page boundary of the
+      // last page before the target, and the first page after the target.
+      SEEK_LOG(LogLevel::Debug, ("Terminating seek at offset=%lld", startOffset));
+      NS_ASSERTION(startTime < aTarget, "Start time must always be less than target");
+      res = Resource(aType)->Seek(nsISeekableStream::NS_SEEK_SET, startOffset);
+      NS_ENSURE_SUCCESS(res,res);
+      if (NS_FAILED(Reset(aType))) {
+        return NS_ERROR_FAILURE;
+      }
+      break;
+    }
+
+    SEEK_LOG(LogLevel::Debug, ("Time at offset %lld is %lld", guess, granuleTime));
+    if (granuleTime < seekTarget && granuleTime > seekLowerBound) {
+      // We're within the fuzzy region in which we want to terminate the search.
+      res = Resource(aType)->Seek(nsISeekableStream::NS_SEEK_SET, pageOffset);
+      NS_ENSURE_SUCCESS(res,res);
+      if (NS_FAILED(Reset(aType))) {
+        return NS_ERROR_FAILURE;
+      }
+      SEEK_LOG(LogLevel::Debug, ("Terminating seek at offset=%lld", pageOffset));
+      break;
+    }
+
+    if (granuleTime >= seekTarget) {
+      // We've landed after the seek target.
+      NS_ASSERTION(pageOffset < endOffset, "offset_end must decrease");
+      endOffset = pageOffset;
+      endTime = granuleTime;
+    } else if (granuleTime < seekTarget) {
+      // Landed before seek target.
+      NS_ASSERTION(pageOffset >= startOffset + startLength,
+        "Bisection point should be at or after end of first page in interval");
+      startOffset = pageOffset;
+      startLength = pageLength;
+      startTime = granuleTime;
+    }
+    NS_ASSERTION(startTime <= seekTarget, "Must be before seek target");
+    NS_ASSERTION(endTime >= seekTarget, "End must be after seek target");
+  }
+
+  SEEK_LOG(LogLevel::Debug, ("Seek complete in %d bisections.", hops));
+
+  return NS_OK;
+}
+
+#undef OGG_DEBUG
+#undef SEEK_DEBUG
+} // namespace mozilla
diff --git a/dom/media/ogg/OggDemuxer.h b/dom/media/ogg/OggDemuxer.h
new file mode 100644
index 0000000000..90c075c98f
--- /dev/null
+++ b/dom/media/ogg/OggDemuxer.h
@@ -0,0 +1,387 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim:set ts=2 sw=2 sts=2 et cindent: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+#if !defined(OggDemuxer_h_)
+#define OggDemuxer_h_
+
+#include "nsTArray.h"
+#include "MediaDataDemuxer.h"
+#include "OggCodecState.h"
+#include "OggCodecStore.h"
+#include "MediaMetadataManager.h"
+
+namespace mozilla {
+
+class OggTrackDemuxer;
+class OggHeaders;
+
+class OggDemuxer : public MediaDataDemuxer
+{
+public:
+  explicit OggDemuxer(MediaResource* aResource);
+
+  RefPtr<InitPromise> Init() override;
+
+  bool HasTrackType(TrackInfo::TrackType aType) const override;
+
+  uint32_t GetNumberTracks(TrackInfo::TrackType aType) const override;
+
+  already_AddRefed<MediaTrackDemuxer> GetTrackDemuxer(TrackInfo::TrackType aType,
+                                                      uint32_t aTrackNumber) override;
+
+  bool IsSeekable() const override;
+
+  UniquePtr<EncryptionInfo> GetCrypto() override;
+
+  // Set the events to notify when chaining is encountered.
+  void SetChainingEvents(TimedMetadataEventProducer* aMetadataEvent,
+                         MediaEventProducer<void>* aOnSeekableEvent);
+
+private:
+
+  // helpers for friend OggTrackDemuxer
+  UniquePtr<TrackInfo> GetTrackInfo(TrackInfo::TrackType aType, size_t aTrackNumber) const;
+
+  struct nsAutoOggSyncState {
+    nsAutoOggSyncState() {
+      ogg_sync_init(&mState);
+    }
+    ~nsAutoOggSyncState() {
+      ogg_sync_clear(&mState);
+    }
+    ogg_sync_state mState;
+  };
+  media::TimeIntervals GetBuffered(TrackInfo::TrackType aType);
+  void FindStartTime(int64_t& aOutStartTime);
+  void FindStartTime(TrackInfo::TrackType, int64_t& aOutStartTime);
+
+  nsresult SeekInternal(TrackInfo::TrackType aType, const media::TimeUnit& aTarget);
+
+  // Seeks to the keyframe preceding the target time using available
+  // keyframe indexes.
+  enum IndexedSeekResult
+  {
+    SEEK_OK,          // Success.
+    SEEK_INDEX_FAIL,  // Failure due to no index, or invalid index.
+    SEEK_FATAL_ERROR  // Error returned by a stream operation.
+  };
+  IndexedSeekResult SeekToKeyframeUsingIndex(TrackInfo::TrackType aType, int64_t aTarget);
+
+  // Rolls back a seek-using-index attempt, returning a failure error code.
+  IndexedSeekResult RollbackIndexedSeek(TrackInfo::TrackType aType, int64_t aOffset);
+
+  // Represents a section of contiguous media, with a start and end offset,
+  // and the timestamps of the start and end of that range, that is cached.
+  // Used to denote the extremities of a range in which we can seek quickly
+  // (because it's cached).
+  class SeekRange
+  {
+  public:
+    SeekRange()
+      : mOffsetStart(0)
+      , mOffsetEnd(0)
+      , mTimeStart(0)
+      , mTimeEnd(0)
+    {}
+
+    SeekRange(int64_t aOffsetStart,
+              int64_t aOffsetEnd,
+              int64_t aTimeStart,
+              int64_t aTimeEnd)
+      : mOffsetStart(aOffsetStart)
+      , mOffsetEnd(aOffsetEnd)
+      , mTimeStart(aTimeStart)
+      , mTimeEnd(aTimeEnd)
+    {}
+
+    bool IsNull() const {
+      return mOffsetStart == 0 &&
+             mOffsetEnd == 0 &&
+             mTimeStart == 0 &&
+             mTimeEnd == 0;
+    }
+
+    int64_t mOffsetStart, mOffsetEnd; // in bytes.
+    int64_t mTimeStart, mTimeEnd; // in usecs.
+  };
+
+  nsresult GetSeekRanges(TrackInfo::TrackType aType, nsTArray<SeekRange>& aRanges);
+  SeekRange SelectSeekRange(TrackInfo::TrackType aType,
+                            const nsTArray<SeekRange>& ranges,
+                            int64_t aTarget,
+                            int64_t aStartTime,
+                            int64_t aEndTime,
+                            bool aExact);
+
+  // Seeks to aTarget usecs in the buffered range aRange using bisection search,
+  // or to the keyframe prior to aTarget if we have video. aAdjustedTarget is
+  // an adjusted version of the target used to account for Opus pre-roll, if
+  // necessary. aStartTime must be the presentation time at the start of media,
+  // and aEndTime the time at end of media. aRanges must be the time/byte ranges
+  // buffered in the media cache as per GetSeekRanges().
+  nsresult SeekInBufferedRange(TrackInfo::TrackType aType,
+                               int64_t aTarget,
+                               int64_t aAdjustedTarget,
+                               int64_t aStartTime,
+                               int64_t aEndTime,
+                               const nsTArray<SeekRange>& aRanges,
+                               const SeekRange& aRange);
+
+  // Seeks to before aTarget usecs in media using bisection search. If the media
+  // has video, this will seek to before the keyframe required to render the
+  // media at aTarget. Will use aRanges in order to narrow the bisection
+  // search space. aStartTime must be the presentation time at the start of
+  // media, and aEndTime the time at end of media. aRanges must be the time/byte
+  // ranges buffered in the media cache as per GetSeekRanges().
+  nsresult SeekInUnbuffered(TrackInfo::TrackType aType,
+                            int64_t aTarget,
+                            int64_t aStartTime,
+                            int64_t aEndTime,
+                            const nsTArray<SeekRange>& aRanges);
+
+  // Performs a seek bisection to move the media stream's read cursor to the
+  // last ogg page boundary which has end time before aTarget usecs on both the
+  // Theora and Vorbis bitstreams. Limits its search to data inside aRange;
+  // i.e. it will only read inside of the aRange's start and end offsets.
+  // aFuzz is the number of usecs of leniency we'll allow; we'll terminate the
+  // seek when we land in the range (aTime - aFuzz, aTime) usecs.
+  nsresult SeekBisection(TrackInfo::TrackType aType,
+                         int64_t aTarget,
+                         const SeekRange& aRange,
+                         uint32_t aFuzz);
+
+  // Chunk size to read when reading Ogg files. Average Ogg page length
+  // is about 4300 bytes, so we read the file in chunks larger than that.
+  static const int PAGE_STEP = 8192;
+
+  enum PageSyncResult
+  {
+    PAGE_SYNC_ERROR = 1,
+    PAGE_SYNC_END_OF_RANGE= 2,
+    PAGE_SYNC_OK = 3
+  };
+  static PageSyncResult PageSync(MediaResourceIndex* aResource,
+                                 ogg_sync_state* aState,
+                                 bool aCachedDataOnly,
+                                 int64_t aOffset,
+                                 int64_t aEndOffset,
+                                 ogg_page* aPage,
+                                 int& aSkippedBytes);
+
+  // Demux next Ogg packet
+  ogg_packet* GetNextPacket(TrackInfo::TrackType aType);
+
+  nsresult Reset(TrackInfo::TrackType aType);
+
+  static const nsString GetKind(const nsCString& aRole);
+  static void InitTrack(MessageField* aMsgInfo,
+                      TrackInfo* aInfo,
+                      bool aEnable);
+
+  // Really private!
+  ~OggDemuxer();
+
+  // Read enough of the file to identify track information and header
+  // packets necessary for decoding to begin.
+  nsresult ReadMetadata();
+
+  // Read a page of data from the Ogg file. Returns true if a page has been
+  // read, false if the page read failed or end of file reached.
+  bool ReadOggPage(TrackInfo::TrackType aType, ogg_page* aPage);
+
+  // Send a page off to the individual streams it belongs to.
+  // Reconstructed packets, if any are ready, will be available
+  // on the individual OggCodecStates.
+  nsresult DemuxOggPage(TrackInfo::TrackType aType, ogg_page* aPage);
+
+  // Read data and demux until a packet is available on the given stream state
+  void DemuxUntilPacketAvailable(TrackInfo::TrackType aType, OggCodecState* aState);
+
+  // Reads and decodes header packets for aState, until either header decode
+  // fails, or is complete. Initializes the codec state before returning.
+  // Returns true if reading headers and initializtion of the stream
+  // succeeds.
+  bool ReadHeaders(TrackInfo::TrackType aType, OggCodecState* aState, OggHeaders& aHeaders);
+
+  // Reads the next link in the chain.
+  bool ReadOggChain(const media::TimeUnit& aLastEndTime);
+
+  // Set this media as being a chain and notifies the state machine that the
+  // media is no longer seekable.
+  void SetChained();
+
+  // Fills aTracks with the serial numbers of each active stream, for use by
+  // various SkeletonState functions.
+  void BuildSerialList(nsTArray<uint32_t>& aTracks);
+
+  // Setup target bitstreams for decoding.
+  void SetupTargetTheora(TheoraState* aTheoraState, OggHeaders& aHeaders);
+  void SetupTargetVorbis(VorbisState* aVorbisState, OggHeaders& aHeaders);
+  void SetupTargetOpus(OpusState* aOpusState, OggHeaders& aHeaders);
+  void SetupTargetFlac(FlacState* aFlacState, OggHeaders& aHeaders);
+  void SetupTargetSkeleton();
+  void SetupMediaTracksInfo(const nsTArray<uint32_t>& aSerials);
+  void FillTags(TrackInfo* aInfo, MetadataTags* aTags);
+
+  // Compute an ogg page's checksum
+  ogg_uint32_t GetPageChecksum(ogg_page* aPage);
+
+  // Get the end time of aEndOffset. This is the playback position we'd reach
+  // after playback finished at aEndOffset.
+  int64_t RangeEndTime(TrackInfo::TrackType aType, int64_t aEndOffset);
+
+  // Get the end time of aEndOffset, without reading before aStartOffset.
+  // This is the playback position we'd reach after playback finished at
+  // aEndOffset. If bool aCachedDataOnly is true, then we'll only read
+  // from data which is cached in the media cached, otherwise we'll do
+  // regular blocking reads from the media stream. If bool aCachedDataOnly
+  // is true, this can safely be called on the main thread, otherwise it
+  // must be called on the state machine thread.
+  int64_t RangeEndTime(TrackInfo::TrackType aType,
+                       int64_t aStartOffset,
+                       int64_t aEndOffset,
+                       bool aCachedDataOnly);
+
+  // Get the start time of the range beginning at aOffset. This is the start
+  // time of the first aType sample we'd be able to play if we
+  // started playback at aOffset.
+  int64_t RangeStartTime(TrackInfo::TrackType aType, int64_t aOffset);
+
+  MediaInfo mInfo;
+  nsTArray<RefPtr<OggTrackDemuxer>> mDemuxers;
+
+  // Map of codec-specific bitstream states.
+  OggCodecStore mCodecStore;
+
+  // Decode state of the Theora bitstream we're decoding, if we have video.
+  TheoraState* mTheoraState;
+
+  // Decode state of the Vorbis bitstream we're decoding, if we have audio.
+  VorbisState* mVorbisState;
+
+  // Decode state of the Opus bitstream we're decoding, if we have one.
+  OpusState* mOpusState;
+
+  // Get the bitstream decode state for the given track type
+  // Decode state of the Flac bitstream we're decoding, if we have one.
+  FlacState* mFlacState;
+
+  OggCodecState* GetTrackCodecState(TrackInfo::TrackType aType) const;
+  TrackInfo::TrackType GetCodecStateType(OggCodecState* aState) const;
+
+  // Represents the user pref media.opus.enabled at the time our
+  // contructor was called. We can't check it dynamically because
+  // we're not on the main thread;
+  bool mOpusEnabled;
+
+  // Decode state of the Skeleton bitstream.
+  SkeletonState* mSkeletonState;
+
+  // Ogg decoding state.
+  struct OggStateContext
+  {
+    explicit OggStateContext(MediaResource* aResource)
+    : mResource(aResource), mNeedKeyframe(true) {}
+    nsAutoOggSyncState mOggState;
+    MediaResourceIndex mResource;
+    Maybe<media::TimeUnit> mStartTime;
+    bool mNeedKeyframe;
+  };
+
+  OggStateContext& OggState(TrackInfo::TrackType aType);
+  ogg_sync_state* OggSyncState(TrackInfo::TrackType aType);
+  MediaResourceIndex* Resource(TrackInfo::TrackType aType);
+  MediaResourceIndex* CommonResource();
+  OggStateContext mAudioOggState;
+  OggStateContext mVideoOggState;
+
+  // Vorbis/Opus/Theora data used to compute timestamps. This is written on the
+  // decoder thread and read on the main thread. All reading on the main
+  // thread must be done after metadataloaded. We can't use the existing
+  // data in the codec states due to threading issues. You must check the
+  // associated mTheoraState or mVorbisState pointer is non-null before
+  // using this codec data.
+  uint32_t mVorbisSerial;
+  uint32_t mOpusSerial;
+  uint32_t mTheoraSerial;
+  uint32_t mFlacSerial;
+
+  vorbis_info mVorbisInfo;
+  int mOpusPreSkip;
+  th_info mTheoraInfo;
+
+  Maybe<int64_t> mStartTime;
+
+  // Booleans to indicate if we have audio and/or video data
+  bool HasVideo() const;
+  bool HasAudio() const;
+  bool HasSkeleton() const
+  {
+    return mSkeletonState != 0 && mSkeletonState->mActive;
+  }
+  bool HaveStartTime () const;
+  bool HaveStartTime (TrackInfo::TrackType aType);
+  int64_t StartTime() const;
+  int64_t StartTime(TrackInfo::TrackType aType);
+
+  // The picture region inside Theora frame to be displayed, if we have
+  // a Theora video track.
+  nsIntRect mPicture;
+
+  // True if we are decoding a chained ogg.
+  bool mIsChained;
+
+  // Total audio duration played so far.
+  media::TimeUnit mDecodedAudioDuration;
+
+  // Events manager
+  TimedMetadataEventProducer* mTimedMetadataEvent;
+  MediaEventProducer<void>* mOnSeekableEvent;
+
+  // This will be populated only if a content change occurs, otherwise it
+  // will be left as null so the original metadata is used.
+  // It is updated once a chained ogg is encountered.
+  // As Ogg chaining is only supported for audio, we only need an audio track
+  // info.
+  RefPtr<SharedTrackInfo> mSharedAudioTrackInfo;
+
+  friend class OggTrackDemuxer;
+};
+
+class OggTrackDemuxer : public MediaTrackDemuxer
+{
+public:
+  OggTrackDemuxer(OggDemuxer* aParent,
+                  TrackInfo::TrackType aType,
+                  uint32_t aTrackNumber);
+
+  UniquePtr<TrackInfo> GetInfo() const override;
+
+  RefPtr<SeekPromise> Seek(media::TimeUnit aTime) override;
+
+  RefPtr<SamplesPromise> GetSamples(int32_t aNumSamples = 1) override;
+
+  void Reset() override;
+
+  RefPtr<SkipAccessPointPromise> SkipToNextRandomAccessPoint(media::TimeUnit aTimeThreshold) override;
+
+  media::TimeIntervals GetBuffered() override;
+
+  void BreakCycles() override;
+
+private:
+  ~OggTrackDemuxer();
+  void SetNextKeyFrameTime();
+  RefPtr<MediaRawData> NextSample();
+  RefPtr<OggDemuxer> mParent;
+  TrackInfo::TrackType mType;
+  UniquePtr<TrackInfo> mInfo;
+
+  // Queued sample extracted by the demuxer, but not yet returned.
+  RefPtr<MediaRawData> mQueuedSample;
+};
+} // namespace mozilla
+
+#endif
diff --git a/dom/media/ogg/OggWriter.cpp b/dom/media/ogg/OggWriter.cpp
new file mode 100644
index 0000000000..bb0dca67b1
--- /dev/null
+++ b/dom/media/ogg/OggWriter.cpp
@@ -0,0 +1,214 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-*/
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+#include "OggWriter.h"
+#include "prtime.h"
+#include "GeckoProfiler.h"
+
+#undef LOG
+#ifdef MOZ_WIDGET_GONK
+#include <android/log.h>
+#define LOG(args...) __android_log_print(ANDROID_LOG_INFO, "MediaEncoder", ## args);
+#else
+#define LOG(args, ...)
+#endif
+
+namespace mozilla {
+
+OggWriter::OggWriter() : ContainerWriter()
+{
+  if (NS_FAILED(Init())) {
+    LOG("ERROR! Fail to initialize the OggWriter.");
+  }
+}
+
+OggWriter::~OggWriter()
+{
+  if (mInitialized) {
+    ogg_stream_clear(&mOggStreamState);
+  }
+  // mPacket's data was always owned by us, no need to ogg_packet_clear.
+}
+
+nsresult
+OggWriter::Init()
+{
+  MOZ_ASSERT(!mInitialized);
+
+  // The serial number (serialno) should be a random number, for the current
+  // implementation where the output file contains only a single stream, this
+  // serialno is used to differentiate between files.
+  srand(static_cast<unsigned>(PR_Now()));
+  int rc = ogg_stream_init(&mOggStreamState, rand());
+
+  mPacket.b_o_s = 1;
+  mPacket.e_o_s = 0;
+  mPacket.granulepos = 0;
+  mPacket.packet = nullptr;
+  mPacket.packetno = 0;
+  mPacket.bytes = 0;
+
+  mInitialized = (rc == 0);
+
+  return (rc == 0) ? NS_OK : NS_ERROR_NOT_INITIALIZED;
+}
+
+nsresult
+OggWriter::WriteEncodedTrack(const EncodedFrameContainer& aData,
+                             uint32_t aFlags)
+{
+  PROFILER_LABEL("OggWriter", "WriteEncodedTrack",
+    js::ProfileEntry::Category::OTHER);
+
+  uint32_t len = aData.GetEncodedFrames().Length();
+  for (uint32_t i = 0; i < len; i++) {
+    if (aData.GetEncodedFrames()[i]->GetFrameType() != EncodedFrame::OPUS_AUDIO_FRAME) {
+      LOG("[OggWriter] wrong encoded data type!");
+      return NS_ERROR_FAILURE;
+    }
+
+    // only pass END_OF_STREAM on the last frame!
+    nsresult rv = WriteEncodedData(aData.GetEncodedFrames()[i]->GetFrameData(),
+                                   aData.GetEncodedFrames()[i]->GetDuration(),
+                                   i < len-1 ? (aFlags & ~ContainerWriter::END_OF_STREAM) :
+                                   aFlags);
+    if (NS_FAILED(rv)) {
+      LOG("%p Failed to WriteEncodedTrack!", this);
+      return rv;
+    }
+  }
+  return NS_OK;
+}
+
+nsresult
+OggWriter::WriteEncodedData(const nsTArray<uint8_t>& aBuffer, int aDuration,
+                            uint32_t aFlags)
+{
+  if (!mInitialized) {
+    LOG("[OggWriter] OggWriter has not initialized!");
+    return NS_ERROR_FAILURE;
+  }
+
+  MOZ_ASSERT(!ogg_stream_eos(&mOggStreamState),
+             "No data can be written after eos has marked.");
+
+  // Set eos flag to true, and once the eos is written to a packet, there must
+  // not be anymore pages after a page has marked as eos.
+  if (aFlags & ContainerWriter::END_OF_STREAM) {
+    LOG("[OggWriter] Set e_o_s flag to true.");
+    mPacket.e_o_s = 1;
+  }
+
+  mPacket.packet = const_cast<uint8_t*>(aBuffer.Elements());
+  mPacket.bytes = aBuffer.Length();
+  mPacket.granulepos += aDuration;
+
+  // 0 returned on success. -1 returned in the event of internal error.
+  // The data in the packet is copied into the internal storage managed by the
+  // mOggStreamState, so we are free to alter the contents of mPacket after
+  // this call has returned.
+  int rc = ogg_stream_packetin(&mOggStreamState, &mPacket);
+  if (rc < 0) {
+    LOG("[OggWriter] Failed in ogg_stream_packetin! (%d).", rc);
+    return NS_ERROR_FAILURE;
+  }
+
+  if (mPacket.b_o_s) {
+    mPacket.b_o_s = 0;
+  }
+  mPacket.packetno++;
+  mPacket.packet = nullptr;
+
+  return NS_OK;
+}
+
+void
+OggWriter::ProduceOggPage(nsTArray<nsTArray<uint8_t> >* aOutputBufs)
+{
+  aOutputBufs->AppendElement();
+  aOutputBufs->LastElement().SetLength(mOggPage.header_len +
+                                       mOggPage.body_len);
+  memcpy(aOutputBufs->LastElement().Elements(), mOggPage.header,
+         mOggPage.header_len);
+  memcpy(aOutputBufs->LastElement().Elements() + mOggPage.header_len,
+         mOggPage.body, mOggPage.body_len);
+}
+
+nsresult
+OggWriter::GetContainerData(nsTArray<nsTArray<uint8_t> >* aOutputBufs,
+                            uint32_t aFlags)
+{
+  int rc = -1;
+  PROFILER_LABEL("OggWriter", "GetContainerData",
+    js::ProfileEntry::Category::OTHER);
+  // Generate the oggOpus Header
+  if (aFlags & ContainerWriter::GET_HEADER) {
+    OpusMetadata* meta = static_cast<OpusMetadata*>(mMetadata.get());
+    NS_ASSERTION(meta, "should have meta data");
+    NS_ASSERTION(meta->GetKind() == TrackMetadataBase::METADATA_OPUS,
+                 "should have Opus meta data");
+
+    nsresult rv = WriteEncodedData(meta->mIdHeader, 0);
+    NS_ENSURE_SUCCESS(rv, rv);
+
+    rc = ogg_stream_flush(&mOggStreamState, &mOggPage);
+    NS_ENSURE_TRUE(rc > 0, NS_ERROR_FAILURE);
+    ProduceOggPage(aOutputBufs);
+
+    rv = WriteEncodedData(meta->mCommentHeader, 0);
+    NS_ENSURE_SUCCESS(rv, rv);
+
+    rc = ogg_stream_flush(&mOggStreamState, &mOggPage);
+    NS_ENSURE_TRUE(rc > 0, NS_ERROR_FAILURE);
+
+    ProduceOggPage(aOutputBufs);
+    return NS_OK;
+
+  // Force generate a page even if the amount of packet data is not enough.
+  // Usually do so after a header packet.
+  } else if (aFlags & ContainerWriter::FLUSH_NEEDED) {
+    // rc = 0 means no packet to put into a page, or an internal error.
+    rc = ogg_stream_flush(&mOggStreamState, &mOggPage);
+  } else {
+    // rc = 0 means insufficient data has accumulated to fill a page, or an
+    // internal error has occurred.
+    rc = ogg_stream_pageout(&mOggStreamState, &mOggPage);
+  }
+
+  if (rc) {
+    ProduceOggPage(aOutputBufs);
+  }
+  if (aFlags & ContainerWriter::FLUSH_NEEDED) {
+    mIsWritingComplete = true;
+  }
+  return (rc > 0) ? NS_OK : NS_ERROR_FAILURE;
+}
+
+nsresult
+OggWriter::SetMetadata(TrackMetadataBase* aMetadata)
+{
+  MOZ_ASSERT(aMetadata);
+
+  PROFILER_LABEL("OggWriter", "SetMetadata",
+    js::ProfileEntry::Category::OTHER);
+
+  if (aMetadata->GetKind() != TrackMetadataBase::METADATA_OPUS) {
+    LOG("wrong meta data type!");
+    return NS_ERROR_FAILURE;
+  }
+  // Validate each field of METADATA
+  mMetadata = static_cast<OpusMetadata*>(aMetadata);
+  if (mMetadata->mIdHeader.Length() == 0) {
+    LOG("miss mIdHeader!");
+    return NS_ERROR_FAILURE;
+  }
+  if (mMetadata->mCommentHeader.Length() == 0) {
+    LOG("miss mCommentHeader!");
+    return NS_ERROR_FAILURE;
+  }
+
+  return NS_OK;
+}
+
+} // namespace mozilla
diff --git a/dom/media/ogg/OggWriter.h b/dom/media/ogg/OggWriter.h
new file mode 100644
index 0000000000..b58bbd6df5
--- /dev/null
+++ b/dom/media/ogg/OggWriter.h
@@ -0,0 +1,52 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-*/
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef OggWriter_h_
+#define OggWriter_h_
+
+#include "ContainerWriter.h"
+#include "OpusTrackEncoder.h"
+#include <ogg/ogg.h>
+
+namespace mozilla {
+/**
+ * WriteEncodedTrack inserts raw packets into Ogg stream (ogg_stream_state), and
+ * GetContainerData outputs an ogg_page when enough packets have been written
+ * to the Ogg stream.
+ * For more details, please reference:
+ * http://www.xiph.org/ogg/doc/libogg/encoding.html
+ */
+class OggWriter : public ContainerWriter
+{
+public:
+  OggWriter();
+  ~OggWriter();
+
+  nsresult WriteEncodedTrack(const EncodedFrameContainer &aData,
+                             uint32_t aFlags = 0) override;
+
+  nsresult GetContainerData(nsTArray<nsTArray<uint8_t> >* aOutputBufs,
+                            uint32_t aFlags = 0) override;
+
+  // Check metadata type integrity and reject unacceptable track encoder.
+  nsresult SetMetadata(TrackMetadataBase* aMetadata) override;
+private:
+  nsresult Init();
+
+  nsresult WriteEncodedData(const nsTArray<uint8_t>& aBuffer, int aDuration,
+                            uint32_t aFlags = 0);
+
+  void ProduceOggPage(nsTArray<nsTArray<uint8_t> >* aOutputBufs);
+  // Store the Medatata from track encoder
+  RefPtr<OpusMetadata> mMetadata;
+
+  ogg_stream_state mOggStreamState;
+  ogg_page mOggPage;
+  ogg_packet mPacket;
+};
+
+} // namespace mozilla
+
+#endif
diff --git a/dom/media/ogg/OpusParser.cpp b/dom/media/ogg/OpusParser.cpp
new file mode 100644
index 0000000000..7e62f6d5fa
--- /dev/null
+++ b/dom/media/ogg/OpusParser.cpp
@@ -0,0 +1,185 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim:set ts=2 sw=2 sts=2 et cindent: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include <algorithm>
+#include "mozilla/EndianUtils.h"
+
+#include "OpusParser.h"
+#include "VideoUtils.h"
+
+#include "opus/opus.h"
+extern "C" {
+#include "opus/opus_multistream.h"
+}
+
+namespace mozilla {
+
+extern LazyLogModule gMediaDecoderLog;
+#define OPUS_LOG(type, msg) MOZ_LOG(gMediaDecoderLog, type, msg)
+
+OpusParser::OpusParser():
+  mRate(0),
+  mNominalRate(0),
+  mChannels(0),
+  mPreSkip(0),
+#ifdef MOZ_SAMPLE_TYPE_FLOAT32
+  mGain(1.0f),
+#else
+  mGain_Q16(65536),
+#endif
+  mChannelMapping(0),
+  mStreams(0),
+  mCoupledStreams(0)
+{ }
+
+bool OpusParser::DecodeHeader(unsigned char* aData, size_t aLength)
+{
+    if (aLength < 19 || memcmp(aData, "OpusHead", 8)) {
+      OPUS_LOG(LogLevel::Debug, ("Invalid Opus file: unrecognized header"));
+      return false;
+    }
+
+    mRate = 48000; // The Opus decoder runs at 48 kHz regardless.
+
+    int version = aData[8];
+    // Accept file format versions 0.x.
+    if ((version & 0xf0) != 0) {
+      OPUS_LOG(LogLevel::Debug, ("Rejecting unknown Opus file version %d", version));
+      return false;
+    }
+
+    mChannels = aData[9];
+    if (mChannels<1) {
+      OPUS_LOG(LogLevel::Debug, ("Invalid Opus file: Number of channels %d", mChannels));
+      return false;
+    }
+
+    mPreSkip = LittleEndian::readUint16(aData + 10);
+    mNominalRate = LittleEndian::readUint32(aData + 12);
+    double gain_dB = LittleEndian::readInt16(aData + 16) / 256.0;
+#ifdef MOZ_SAMPLE_TYPE_FLOAT32
+    mGain = static_cast<float>(pow(10,0.05*gain_dB));
+#else
+    mGain_Q16 = static_cast<int32_t>(std::min(65536*pow(10,0.05*gain_dB)+0.5,
+                                            static_cast<double>(INT32_MAX)));
+#endif
+    mChannelMapping = aData[18];
+
+    if (mChannelMapping == 0) {
+      // Mapping family 0 only allows two channels
+      if (mChannels>2) {
+        OPUS_LOG(LogLevel::Debug, ("Invalid Opus file: too many channels (%d) for"
+                           " mapping family 0.", mChannels));
+        return false;
+      }
+      mStreams = 1;
+      mCoupledStreams = mChannels - 1;
+      mMappingTable[0] = 0;
+      mMappingTable[1] = 1;
+    } else if (mChannelMapping == 1 || mChannelMapping == 255) {
+      // Currently only up to 8 channels are defined for mapping family 1 and we
+      // only supports only up to 8 channels for mapping family 255.
+      if (mChannels>8) {
+        OPUS_LOG(LogLevel::Debug, ("Invalid Opus file: too many channels (%d) for"
+                           " mapping family 1.", mChannels));
+        return false;
+      }
+      if (aLength>static_cast<unsigned>(20+mChannels)) {
+        mStreams = aData[19];
+        mCoupledStreams = aData[20];
+        int i;
+        for (i=0; i<mChannels; i++)
+          mMappingTable[i] = aData[21+i];
+      } else {
+        OPUS_LOG(LogLevel::Debug, ("Invalid Opus file: channel mapping %d,"
+                           " but no channel mapping table", mChannelMapping));
+        return false;
+      }
+    } else {
+      OPUS_LOG(LogLevel::Debug, ("Invalid Opus file: unsupported channel mapping "
+                         "family %d", mChannelMapping));
+      return false;
+    }
+    if (mStreams < 1) {
+      OPUS_LOG(LogLevel::Debug, ("Invalid Opus file: no streams"));
+      return false;
+    }
+    if (mCoupledStreams > mStreams) {
+      OPUS_LOG(LogLevel::Debug, ("Invalid Opus file: more coupled streams (%d) than "
+                         "total streams (%d)", mCoupledStreams, mStreams));
+      return false;
+    }
+
+#ifdef DEBUG
+    OPUS_LOG(LogLevel::Debug, ("Opus stream header:"));
+    OPUS_LOG(LogLevel::Debug, (" channels: %d", mChannels));
+    OPUS_LOG(LogLevel::Debug, ("  preskip: %d", mPreSkip));
+    OPUS_LOG(LogLevel::Debug, (" original: %d Hz", mNominalRate));
+    OPUS_LOG(LogLevel::Debug, ("     gain: %.2f dB", gain_dB));
+    OPUS_LOG(LogLevel::Debug, ("Channel Mapping:"));
+    OPUS_LOG(LogLevel::Debug, ("   family: %d", mChannelMapping));
+    OPUS_LOG(LogLevel::Debug, ("  streams: %d", mStreams));
+#endif
+  return true;
+}
+
+bool OpusParser::DecodeTags(unsigned char* aData, size_t aLength)
+{
+  if (aLength < 16 || memcmp(aData, "OpusTags", 8))
+    return false;
+
+  // Copy out the raw comment lines, but only do basic validation
+  // checks against the string packing: too little data, too many
+  // comments, or comments that are too long. Rejecting these cases
+  // helps reduce the propagation of broken files.
+  // We do not ensure they are valid UTF-8 here, nor do we validate
+  // the required ASCII_TAG=value format of the user comments.
+  const unsigned char* buf = aData + 8;
+  uint32_t bytes = aLength - 8;
+  uint32_t len;
+  // Read the vendor string.
+  len = LittleEndian::readUint32(buf);
+  buf += 4;
+  bytes -= 4;
+  if (len > bytes)
+    return false;
+  mVendorString = nsCString(reinterpret_cast<const char*>(buf), len);
+  buf += len;
+  bytes -= len;
+  // Read the user comments.
+  if (bytes < 4)
+    return false;
+  uint32_t ncomments = LittleEndian::readUint32(buf);
+  buf += 4;
+  bytes -= 4;
+  // If there are so many comments even their length fields
+  // won't fit in the packet, stop reading now.
+  if (ncomments > (bytes>>2))
+    return false;
+  for (uint32_t i = 0; i < ncomments; i++) {
+    if (bytes < 4)
+      return false;
+    len = LittleEndian::readUint32(buf);
+    buf += 4;
+    bytes -= 4;
+    if (len > bytes)
+      return false;
+    mTags.AppendElement(nsCString(reinterpret_cast<const char*>(buf), len));
+    buf += len;
+    bytes -= len;
+  }
+
+#ifdef DEBUG
+  OPUS_LOG(LogLevel::Debug, ("Opus metadata header:"));
+  OPUS_LOG(LogLevel::Debug, ("  vendor: %s", mVendorString.get()));
+  for (uint32_t i = 0; i < mTags.Length(); i++) {
+    OPUS_LOG(LogLevel::Debug, (" %s", mTags[i].get()));
+  }
+#endif
+  return true;
+}
+
+} // namespace mozilla
diff --git a/dom/media/ogg/OpusParser.h b/dom/media/ogg/OpusParser.h
new file mode 100644
index 0000000000..0c6d9c940a
--- /dev/null
+++ b/dom/media/ogg/OpusParser.h
@@ -0,0 +1,48 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim:set ts=2 sw=2 sts=2 et cindent: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+#if !defined(OpusParser_h_)
+#define OpusParser_h_
+
+#include "nsTArray.h"
+#include "nsString.h"
+
+namespace mozilla {
+
+class OpusParser
+{
+public:
+  OpusParser();
+
+  bool DecodeHeader(unsigned char* aData, size_t aLength);
+  bool DecodeTags(unsigned char* aData, size_t aLength);
+
+  // Various fields from the Ogg Opus header.
+  int mRate;        // Sample rate the decoder uses (always 48 kHz).
+  uint32_t mNominalRate; // Original sample rate of the data (informational).
+  int mChannels;    // Number of channels the stream encodes.
+  uint16_t mPreSkip; // Number of samples to strip after decoder reset.
+#ifdef MOZ_SAMPLE_TYPE_FLOAT32
+  float mGain;      // Gain to apply to decoder output.
+#else
+  int32_t mGain_Q16; // Gain to apply to the decoder output.
+#endif
+  int mChannelMapping; // Channel mapping family.
+  int mStreams;     // Number of packed streams in each packet.
+  int mCoupledStreams; // Number of packed coupled streams in each packet.
+  unsigned char mMappingTable[255]; // Channel mapping table.
+
+  // Granule position (end sample) of the last decoded Opus packet. This is
+  // used to calculate the amount we should trim from the last packet.
+  int64_t mPrevPacketGranulepos;
+
+  nsTArray<nsCString> mTags; // Unparsed comment strings from the header.
+
+  nsCString mVendorString;   // Encoder vendor string from the header.
+};
+
+} // namespace mozilla
+
+#endif
diff --git a/dom/media/ogg/moz.build b/dom/media/ogg/moz.build
new file mode 100644
index 0000000000..07e195b6f7
--- /dev/null
+++ b/dom/media/ogg/moz.build
@@ -0,0 +1,25 @@
+# -*- Mode: python; indent-tabs-mode: nil; tab-width: 40 -*-
+# vim: set filetype=python:
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+EXPORTS += [
+    'OggCodecState.h',
+    'OggCodecStore.h',
+    'OggDecoder.h',
+    'OggDemuxer.h',
+    'OggWriter.h',
+    'OpusParser.h',
+]
+
+UNIFIED_SOURCES += [
+    'OggCodecState.cpp',
+    'OggCodecStore.cpp',
+    'OggDecoder.cpp',
+    'OggDemuxer.cpp',
+    'OggWriter.cpp',
+    'OpusParser.cpp',
+]
+
+FINAL_LIBRARY = 'xul'