diff options
Diffstat (limited to 'media/libaom/src/av1/encoder/pass2_strategy.c')
| -rw-r--r-- | media/libaom/src/av1/encoder/pass2_strategy.c | 2895 |
1 files changed, 2895 insertions, 0 deletions
diff --git a/media/libaom/src/av1/encoder/pass2_strategy.c b/media/libaom/src/av1/encoder/pass2_strategy.c new file mode 100644 index 0000000000..6adc1fbf9d --- /dev/null +++ b/media/libaom/src/av1/encoder/pass2_strategy.c @@ -0,0 +1,2895 @@ +/* + * Copyright (c) 2019, Alliance for Open Media. All rights reserved + * + * This source code is subject to the terms of the BSD 2 Clause License and + * the Alliance for Open Media Patent License 1.0. If the BSD 2 Clause License + * was not distributed with this source code in the LICENSE file, you can + * obtain it at www.aomedia.org/license/software. If the Alliance for Open + * Media Patent License 1.0 was not distributed with this source code in the + * PATENTS file, you can obtain it at www.aomedia.org/license/patent. + */ + +#include <stdint.h> + +#include "config/aom_config.h" +#include "config/aom_scale_rtcd.h" + +#include "aom/aom_codec.h" +#include "aom/aom_encoder.h" + +#include "aom_ports/system_state.h" + +#include "av1/common/av1_common_int.h" + +#include "av1/encoder/encoder.h" +#include "av1/encoder/firstpass.h" +#include "av1/encoder/gop_structure.h" +#include "av1/encoder/pass2_strategy.h" +#include "av1/encoder/ratectrl.h" +#include "av1/encoder/tpl_model.h" +#include "av1/encoder/use_flat_gop_model_params.h" +#include "av1/encoder/encode_strategy.h" + +#define DEFAULT_KF_BOOST 2300 +#define DEFAULT_GF_BOOST 2000 +#define GROUP_ADAPTIVE_MAXQ 1 +static void init_gf_stats(GF_GROUP_STATS *gf_stats); + +// Calculate an active area of the image that discounts formatting +// bars and partially discounts other 0 energy areas. +#define MIN_ACTIVE_AREA 0.5 +#define MAX_ACTIVE_AREA 1.0 +static double calculate_active_area(const FRAME_INFO *frame_info, + const FIRSTPASS_STATS *this_frame) { + const double active_pct = + 1.0 - + ((this_frame->intra_skip_pct / 2) + + ((this_frame->inactive_zone_rows * 2) / (double)frame_info->mb_rows)); + return fclamp(active_pct, MIN_ACTIVE_AREA, MAX_ACTIVE_AREA); +} + +// Calculate a modified Error used in distributing bits between easier and +// harder frames. +#define ACT_AREA_CORRECTION 0.5 +static double calculate_modified_err(const FRAME_INFO *frame_info, + const TWO_PASS *twopass, + const AV1EncoderConfig *oxcf, + const FIRSTPASS_STATS *this_frame) { + const FIRSTPASS_STATS *const stats = twopass->stats_buf_ctx->total_stats; + if (stats == NULL) { + return 0; + } + const double av_weight = stats->weight / stats->count; + const double av_err = (stats->coded_error * av_weight) / stats->count; + double modified_error = + av_err * pow(this_frame->coded_error * this_frame->weight / + DOUBLE_DIVIDE_CHECK(av_err), + oxcf->two_pass_vbrbias / 100.0); + + // Correction for active area. Frames with a reduced active area + // (eg due to formatting bars) have a higher error per mb for the + // remaining active MBs. The correction here assumes that coding + // 0.5N blocks of complexity 2X is a little easier than coding N + // blocks of complexity X. + modified_error *= + pow(calculate_active_area(frame_info, this_frame), ACT_AREA_CORRECTION); + + return fclamp(modified_error, twopass->modified_error_min, + twopass->modified_error_max); +} + +// Resets the first pass file to the given position using a relative seek from +// the current position. +static void reset_fpf_position(TWO_PASS *p, const FIRSTPASS_STATS *position) { + p->stats_in = position; +} + +static int input_stats(TWO_PASS *p, FIRSTPASS_STATS *fps) { + if (p->stats_in >= p->stats_buf_ctx->stats_in_end) return EOF; + + *fps = *p->stats_in; + ++p->stats_in; + return 1; +} + +static int input_stats_lap(TWO_PASS *p, FIRSTPASS_STATS *fps) { + if (p->stats_in >= p->stats_buf_ctx->stats_in_end) return EOF; + + *fps = *p->stats_in; + /* Move old stats[0] out to accommodate for next frame stats */ + memmove(p->frame_stats_arr[0], p->frame_stats_arr[1], + (p->stats_buf_ctx->stats_in_end - p->stats_in - 1) * + sizeof(FIRSTPASS_STATS)); + p->stats_buf_ctx->stats_in_end--; + return 1; +} + +// Read frame stats at an offset from the current position. +static const FIRSTPASS_STATS *read_frame_stats(const TWO_PASS *p, int offset) { + if ((offset >= 0 && p->stats_in + offset >= p->stats_buf_ctx->stats_in_end) || + (offset < 0 && p->stats_in + offset < p->stats_buf_ctx->stats_in_start)) { + return NULL; + } + + return &p->stats_in[offset]; +} + +static void subtract_stats(FIRSTPASS_STATS *section, + const FIRSTPASS_STATS *frame) { + section->frame -= frame->frame; + section->weight -= frame->weight; + section->intra_error -= frame->intra_error; + section->frame_avg_wavelet_energy -= frame->frame_avg_wavelet_energy; + section->coded_error -= frame->coded_error; + section->sr_coded_error -= frame->sr_coded_error; + section->pcnt_inter -= frame->pcnt_inter; + section->pcnt_motion -= frame->pcnt_motion; + section->pcnt_second_ref -= frame->pcnt_second_ref; + section->pcnt_neutral -= frame->pcnt_neutral; + section->intra_skip_pct -= frame->intra_skip_pct; + section->inactive_zone_rows -= frame->inactive_zone_rows; + section->inactive_zone_cols -= frame->inactive_zone_cols; + section->MVr -= frame->MVr; + section->mvr_abs -= frame->mvr_abs; + section->MVc -= frame->MVc; + section->mvc_abs -= frame->mvc_abs; + section->MVrv -= frame->MVrv; + section->MVcv -= frame->MVcv; + section->mv_in_out_count -= frame->mv_in_out_count; + section->new_mv_count -= frame->new_mv_count; + section->count -= frame->count; + section->duration -= frame->duration; +} + +// This function returns the maximum target rate per frame. +static int frame_max_bits(const RATE_CONTROL *rc, + const AV1EncoderConfig *oxcf) { + int64_t max_bits = ((int64_t)rc->avg_frame_bandwidth * + (int64_t)oxcf->two_pass_vbrmax_section) / + 100; + if (max_bits < 0) + max_bits = 0; + else if (max_bits > rc->max_frame_bandwidth) + max_bits = rc->max_frame_bandwidth; + + return (int)max_bits; +} + +static const double q_pow_term[(QINDEX_RANGE >> 5) + 1] = { 0.65, 0.70, 0.75, + 0.80, 0.85, 0.90, + 0.95, 0.95, 0.95 }; +#define ERR_DIVISOR 96.0 +static double calc_correction_factor(double err_per_mb, int q) { + const double error_term = err_per_mb / ERR_DIVISOR; + const int index = q >> 5; + // Adjustment to power term based on qindex + const double power_term = + q_pow_term[index] + + (((q_pow_term[index + 1] - q_pow_term[index]) * (q % 32)) / 32.0); + assert(error_term >= 0.0); + return fclamp(pow(error_term, power_term), 0.05, 5.0); +} + +static void twopass_update_bpm_factor(TWO_PASS *twopass) { + // Based on recent history adjust expectations of bits per macroblock. + double last_group_rate_err = + (double)twopass->rolling_arf_group_actual_bits / + DOUBLE_DIVIDE_CHECK((double)twopass->rolling_arf_group_target_bits); + last_group_rate_err = AOMMAX(0.25, AOMMIN(4.0, last_group_rate_err)); + twopass->bpm_factor *= (3.0 + last_group_rate_err) / 4.0; + twopass->bpm_factor = AOMMAX(0.25, AOMMIN(4.0, twopass->bpm_factor)); +} + +static int qbpm_enumerator(int rate_err_tol) { + return 1350000 + ((300000 * AOMMIN(75, AOMMAX(rate_err_tol - 25, 0))) / 75); +} + +// Similar to find_qindex_by_rate() function in ratectrl.c, but includes +// calculation of a correction_factor. +static int find_qindex_by_rate_with_correction( + int desired_bits_per_mb, aom_bit_depth_t bit_depth, double error_per_mb, + double group_weight_factor, int rate_err_tol, int best_qindex, + int worst_qindex) { + assert(best_qindex <= worst_qindex); + int low = best_qindex; + int high = worst_qindex; + + while (low < high) { + const int mid = (low + high) >> 1; + const double mid_factor = calc_correction_factor(error_per_mb, mid); + const double q = av1_convert_qindex_to_q(mid, bit_depth); + const int enumerator = qbpm_enumerator(rate_err_tol); + const int mid_bits_per_mb = + (int)((enumerator * mid_factor * group_weight_factor) / q); + + if (mid_bits_per_mb > desired_bits_per_mb) { + low = mid + 1; + } else { + high = mid; + } + } + return low; +} + +static int get_twopass_worst_quality(AV1_COMP *cpi, const double section_err, + double inactive_zone, + int section_target_bandwidth, + double group_weight_factor) { + const RATE_CONTROL *const rc = &cpi->rc; + const AV1EncoderConfig *const oxcf = &cpi->oxcf; + + inactive_zone = fclamp(inactive_zone, 0.0, 1.0); + + if (section_target_bandwidth <= 0) { + return rc->worst_quality; // Highest value allowed + } else { + const int num_mbs = (cpi->oxcf.resize_mode != RESIZE_NONE) + ? cpi->initial_mbs + : cpi->common.mi_params.MBs; + const int active_mbs = AOMMAX(1, num_mbs - (int)(num_mbs * inactive_zone)); + const double av_err_per_mb = section_err / active_mbs; + const int target_norm_bits_per_mb = + (int)((uint64_t)section_target_bandwidth << BPER_MB_NORMBITS) / + active_mbs; + int rate_err_tol = + AOMMIN(cpi->oxcf.under_shoot_pct, cpi->oxcf.over_shoot_pct); + + twopass_update_bpm_factor(&cpi->twopass); + // Try and pick a max Q that will be high enough to encode the + // content at the given rate. + int q = find_qindex_by_rate_with_correction( + target_norm_bits_per_mb, cpi->common.seq_params.bit_depth, + av_err_per_mb, group_weight_factor, rate_err_tol, rc->best_quality, + rc->worst_quality); + + // Restriction on active max q for constrained quality mode. + if (cpi->oxcf.rc_mode == AOM_CQ) q = AOMMAX(q, oxcf->cq_level); + return q; + } +} + +#define SR_DIFF_PART 0.0015 +#define MOTION_AMP_PART 0.003 +#define INTRA_PART 0.005 +#define DEFAULT_DECAY_LIMIT 0.75 +#define LOW_SR_DIFF_TRHESH 0.1 +#define SR_DIFF_MAX 128.0 +#define NCOUNT_FRAME_II_THRESH 5.0 + +static double get_sr_decay_rate(const FRAME_INFO *frame_info, + const FIRSTPASS_STATS *frame) { + const int num_mbs = frame_info->num_mbs; + double sr_diff = (frame->sr_coded_error - frame->coded_error) / num_mbs; + double sr_decay = 1.0; + double modified_pct_inter; + double modified_pcnt_intra; + const double motion_amplitude_factor = + frame->pcnt_motion * ((frame->mvc_abs + frame->mvr_abs) / 2); + + modified_pct_inter = frame->pcnt_inter; + if ((frame->intra_error / DOUBLE_DIVIDE_CHECK(frame->coded_error)) < + (double)NCOUNT_FRAME_II_THRESH) { + modified_pct_inter = frame->pcnt_inter - frame->pcnt_neutral; + } + modified_pcnt_intra = 100 * (1.0 - modified_pct_inter); + + if ((sr_diff > LOW_SR_DIFF_TRHESH)) { + sr_diff = AOMMIN(sr_diff, SR_DIFF_MAX); + sr_decay = 1.0 - (SR_DIFF_PART * sr_diff) - + (MOTION_AMP_PART * motion_amplitude_factor) - + (INTRA_PART * modified_pcnt_intra); + } + return AOMMAX(sr_decay, AOMMIN(DEFAULT_DECAY_LIMIT, modified_pct_inter)); +} + +// This function gives an estimate of how badly we believe the prediction +// quality is decaying from frame to frame. +static double get_zero_motion_factor(const FRAME_INFO *frame_info, + const FIRSTPASS_STATS *frame) { + const double zero_motion_pct = frame->pcnt_inter - frame->pcnt_motion; + double sr_decay = get_sr_decay_rate(frame_info, frame); + return AOMMIN(sr_decay, zero_motion_pct); +} + +#define ZM_POWER_FACTOR 0.75 + +static double get_prediction_decay_rate(const FRAME_INFO *frame_info, + const FIRSTPASS_STATS *next_frame) { + const double sr_decay_rate = get_sr_decay_rate(frame_info, next_frame); + const double zero_motion_factor = + (0.95 * pow((next_frame->pcnt_inter - next_frame->pcnt_motion), + ZM_POWER_FACTOR)); + + return AOMMAX(zero_motion_factor, + (sr_decay_rate + ((1.0 - sr_decay_rate) * zero_motion_factor))); +} + +// Function to test for a condition where a complex transition is followed +// by a static section. For example in slide shows where there is a fade +// between slides. This is to help with more optimal kf and gf positioning. +static int detect_transition_to_still(TWO_PASS *const twopass, + const int min_gf_interval, + const int frame_interval, + const int still_interval, + const double loop_decay_rate, + const double last_decay_rate) { + // Break clause to detect very still sections after motion + // For example a static image after a fade or other transition + // instead of a clean scene cut. + if (frame_interval > min_gf_interval && loop_decay_rate >= 0.999 && + last_decay_rate < 0.9) { + int j; + // Look ahead a few frames to see if static condition persists... + for (j = 0; j < still_interval; ++j) { + const FIRSTPASS_STATS *stats = &twopass->stats_in[j]; + if (stats >= twopass->stats_buf_ctx->stats_in_end) break; + + if (stats->pcnt_inter - stats->pcnt_motion < 0.999) break; + } + // Only if it does do we signal a transition to still. + return j == still_interval; + } + return 0; +} + +// This function detects a flash through the high relative pcnt_second_ref +// score in the frame following a flash frame. The offset passed in should +// reflect this. +static int detect_flash(const TWO_PASS *twopass, const int offset) { + const FIRSTPASS_STATS *const next_frame = read_frame_stats(twopass, offset); + + // What we are looking for here is a situation where there is a + // brief break in prediction (such as a flash) but subsequent frames + // are reasonably well predicted by an earlier (pre flash) frame. + // The recovery after a flash is indicated by a high pcnt_second_ref + // compared to pcnt_inter. + return next_frame != NULL && + next_frame->pcnt_second_ref > next_frame->pcnt_inter && + next_frame->pcnt_second_ref >= 0.5; +} + +// Update the motion related elements to the GF arf boost calculation. +static void accumulate_frame_motion_stats(const FIRSTPASS_STATS *stats, + GF_GROUP_STATS *gf_stats) { + const double pct = stats->pcnt_motion; + + // Accumulate Motion In/Out of frame stats. + gf_stats->this_frame_mv_in_out = stats->mv_in_out_count * pct; + gf_stats->mv_in_out_accumulator += gf_stats->this_frame_mv_in_out; + gf_stats->abs_mv_in_out_accumulator += fabs(gf_stats->this_frame_mv_in_out); + + // Accumulate a measure of how uniform (or conversely how random) the motion + // field is (a ratio of abs(mv) / mv). + if (pct > 0.05) { + const double mvr_ratio = + fabs(stats->mvr_abs) / DOUBLE_DIVIDE_CHECK(fabs(stats->MVr)); + const double mvc_ratio = + fabs(stats->mvc_abs) / DOUBLE_DIVIDE_CHECK(fabs(stats->MVc)); + + gf_stats->mv_ratio_accumulator += + pct * (mvr_ratio < stats->mvr_abs ? mvr_ratio : stats->mvr_abs); + gf_stats->mv_ratio_accumulator += + pct * (mvc_ratio < stats->mvc_abs ? mvc_ratio : stats->mvc_abs); + } +} + +static void accumulate_this_frame_stats(const FIRSTPASS_STATS *stats, + const double mod_frame_err, + GF_GROUP_STATS *gf_stats) { + gf_stats->gf_group_err += mod_frame_err; +#if GROUP_ADAPTIVE_MAXQ + gf_stats->gf_group_raw_error += stats->coded_error; +#endif + gf_stats->gf_group_skip_pct += stats->intra_skip_pct; + gf_stats->gf_group_inactive_zone_rows += stats->inactive_zone_rows; +} + +static void accumulate_next_frame_stats( + const FIRSTPASS_STATS *stats, const FRAME_INFO *frame_info, + TWO_PASS *const twopass, const int flash_detected, + const int frames_since_key, const int cur_idx, const int can_disable_arf, + const int min_gf_interval, GF_GROUP_STATS *gf_stats) { + accumulate_frame_motion_stats(stats, gf_stats); + // sum up the metric values of current gf group + gf_stats->avg_sr_coded_error += stats->sr_coded_error; + gf_stats->avg_tr_coded_error += stats->tr_coded_error; + gf_stats->avg_pcnt_second_ref += stats->pcnt_second_ref; + gf_stats->avg_pcnt_third_ref += stats->pcnt_third_ref; + gf_stats->avg_new_mv_count += stats->new_mv_count; + gf_stats->avg_wavelet_energy += stats->frame_avg_wavelet_energy; + if (fabs(stats->raw_error_stdev) > 0.000001) { + gf_stats->non_zero_stdev_count++; + gf_stats->avg_raw_err_stdev += stats->raw_error_stdev; + } + + // Accumulate the effect of prediction quality decay + if (!flash_detected) { + gf_stats->last_loop_decay_rate = gf_stats->loop_decay_rate; + gf_stats->loop_decay_rate = get_prediction_decay_rate(frame_info, stats); + + gf_stats->decay_accumulator = + gf_stats->decay_accumulator * gf_stats->loop_decay_rate; + + // Monitor for static sections. + if ((frames_since_key + cur_idx - 1) > 1) { + gf_stats->zero_motion_accumulator = + AOMMIN(gf_stats->zero_motion_accumulator, + get_zero_motion_factor(frame_info, stats)); + } + + // Break clause to detect very still sections after motion. For example, + // a static image after a fade or other transition. + if (can_disable_arf && + detect_transition_to_still(twopass, min_gf_interval, cur_idx, 5, + gf_stats->loop_decay_rate, + gf_stats->last_loop_decay_rate)) { + gf_stats->allow_alt_ref = 0; + } + } +} + +static void average_gf_stats(const int total_frame, + const FIRSTPASS_STATS *last_stat, + GF_GROUP_STATS *gf_stats) { + if (total_frame) { + gf_stats->avg_sr_coded_error /= total_frame; + gf_stats->avg_tr_coded_error /= total_frame; + gf_stats->avg_pcnt_second_ref /= total_frame; + if (total_frame - 1) { + gf_stats->avg_pcnt_third_ref_nolast = + (gf_stats->avg_pcnt_third_ref - last_stat->pcnt_third_ref) / + (total_frame - 1); + } else { + gf_stats->avg_pcnt_third_ref_nolast = + gf_stats->avg_pcnt_third_ref / total_frame; + } + gf_stats->avg_pcnt_third_ref /= total_frame; + gf_stats->avg_new_mv_count /= total_frame; + gf_stats->avg_wavelet_energy /= total_frame; + } + + if (gf_stats->non_zero_stdev_count) + gf_stats->avg_raw_err_stdev /= gf_stats->non_zero_stdev_count; +} + +static void get_features_from_gf_stats(const GF_GROUP_STATS *gf_stats, + const GF_FRAME_STATS *first_frame, + const GF_FRAME_STATS *last_frame, + const int num_mbs, + const int constrained_gf_group, + const int kf_zeromotion_pct, + const int num_frames, float *features) { + *features++ = (float)gf_stats->abs_mv_in_out_accumulator; + *features++ = (float)(gf_stats->avg_new_mv_count / num_mbs); + *features++ = (float)gf_stats->avg_pcnt_second_ref; + *features++ = (float)gf_stats->avg_pcnt_third_ref; + *features++ = (float)gf_stats->avg_pcnt_third_ref_nolast; + *features++ = (float)(gf_stats->avg_sr_coded_error / num_mbs); + *features++ = (float)(gf_stats->avg_tr_coded_error / num_mbs); + *features++ = (float)(gf_stats->avg_wavelet_energy / num_mbs); + *features++ = (float)(constrained_gf_group); + *features++ = (float)gf_stats->decay_accumulator; + *features++ = (float)(first_frame->frame_coded_error / num_mbs); + *features++ = (float)(first_frame->frame_sr_coded_error / num_mbs); + *features++ = (float)(first_frame->frame_tr_coded_error / num_mbs); + *features++ = (float)(first_frame->frame_err / num_mbs); + *features++ = (float)(kf_zeromotion_pct); + *features++ = (float)(last_frame->frame_coded_error / num_mbs); + *features++ = (float)(last_frame->frame_sr_coded_error / num_mbs); + *features++ = (float)(last_frame->frame_tr_coded_error / num_mbs); + *features++ = (float)num_frames; + *features++ = (float)gf_stats->mv_ratio_accumulator; + *features++ = (float)gf_stats->non_zero_stdev_count; +} + +#define BOOST_FACTOR 12.5 +static double baseline_err_per_mb(const FRAME_INFO *frame_info) { + unsigned int screen_area = frame_info->frame_height * frame_info->frame_width; + + // Use a different error per mb factor for calculating boost for + // different formats. + if (screen_area <= 640 * 360) { + return 500.0; + } else { + return 1000.0; + } +} + +static double calc_frame_boost(const RATE_CONTROL *rc, + const FRAME_INFO *frame_info, + const FIRSTPASS_STATS *this_frame, + double this_frame_mv_in_out, double max_boost) { + double frame_boost; + const double lq = av1_convert_qindex_to_q(rc->avg_frame_qindex[INTER_FRAME], + frame_info->bit_depth); + const double boost_q_correction = AOMMIN((0.5 + (lq * 0.015)), 1.5); + const double active_area = calculate_active_area(frame_info, this_frame); + int num_mbs = frame_info->num_mbs; + + // Correct for any inactive region in the image + num_mbs = (int)AOMMAX(1, num_mbs * active_area); + + // Underlying boost factor is based on inter error ratio. + frame_boost = AOMMAX(baseline_err_per_mb(frame_info) * num_mbs, + this_frame->intra_error * active_area) / + DOUBLE_DIVIDE_CHECK(this_frame->coded_error); + frame_boost = frame_boost * BOOST_FACTOR * boost_q_correction; + + // Increase boost for frames where new data coming into frame (e.g. zoom out). + // Slightly reduce boost if there is a net balance of motion out of the frame + // (zoom in). The range for this_frame_mv_in_out is -1.0 to +1.0. + if (this_frame_mv_in_out > 0.0) + frame_boost += frame_boost * (this_frame_mv_in_out * 2.0); + // In the extreme case the boost is halved. + else + frame_boost += frame_boost * (this_frame_mv_in_out / 2.0); + + return AOMMIN(frame_boost, max_boost * boost_q_correction); +} + +static double calc_kf_frame_boost(const RATE_CONTROL *rc, + const FRAME_INFO *frame_info, + const FIRSTPASS_STATS *this_frame, + double *sr_accumulator, double max_boost) { + double frame_boost; + const double lq = av1_convert_qindex_to_q(rc->avg_frame_qindex[INTER_FRAME], + frame_info->bit_depth); + const double boost_q_correction = AOMMIN((0.50 + (lq * 0.015)), 2.00); + const double active_area = calculate_active_area(frame_info, this_frame); + int num_mbs = frame_info->num_mbs; + + // Correct for any inactive region in the image + num_mbs = (int)AOMMAX(1, num_mbs * active_area); + + // Underlying boost factor is based on inter error ratio. + frame_boost = AOMMAX(baseline_err_per_mb(frame_info) * num_mbs, + this_frame->intra_error * active_area) / + DOUBLE_DIVIDE_CHECK( + (this_frame->coded_error + *sr_accumulator) * active_area); + + // Update the accumulator for second ref error difference. + // This is intended to give an indication of how much the coded error is + // increasing over time. + *sr_accumulator += (this_frame->sr_coded_error - this_frame->coded_error); + *sr_accumulator = AOMMAX(0.0, *sr_accumulator); + + // Q correction and scaling + // The 40.0 value here is an experimentally derived baseline minimum. + // This value is in line with the minimum per frame boost in the alt_ref + // boost calculation. + frame_boost = ((frame_boost + 40.0) * boost_q_correction); + + return AOMMIN(frame_boost, max_boost * boost_q_correction); +} + +static int get_projected_gfu_boost(const RATE_CONTROL *rc, int gfu_boost, + int frames_to_project, + int num_stats_used_for_gfu_boost) { + /* + * If frames_to_project is equal to num_stats_used_for_gfu_boost, + * it means that gfu_boost was calculated over frames_to_project to + * begin with(ie; all stats required were available), hence return + * the original boost. + */ + if (num_stats_used_for_gfu_boost >= frames_to_project) return gfu_boost; + + double min_boost_factor = sqrt(rc->baseline_gf_interval); + // Get the current tpl factor (number of frames = frames_to_project). + double tpl_factor = av1_get_gfu_boost_projection_factor( + min_boost_factor, MAX_GFUBOOST_FACTOR, frames_to_project); + // Get the tpl factor when number of frames = num_stats_used_for_prior_boost. + double tpl_factor_num_stats = av1_get_gfu_boost_projection_factor( + min_boost_factor, MAX_GFUBOOST_FACTOR, num_stats_used_for_gfu_boost); + int projected_gfu_boost = + (int)rint((tpl_factor * gfu_boost) / tpl_factor_num_stats); + return projected_gfu_boost; +} + +#define GF_MAX_BOOST 90.0 +#define MIN_DECAY_FACTOR 0.01 +int av1_calc_arf_boost(const TWO_PASS *twopass, const RATE_CONTROL *rc, + FRAME_INFO *frame_info, int offset, int f_frames, + int b_frames, int *num_fpstats_used, + int *num_fpstats_required) { + int i; + GF_GROUP_STATS gf_stats; + init_gf_stats(&gf_stats); + double boost_score = (double)NORMAL_BOOST; + int arf_boost; + int flash_detected = 0; + if (num_fpstats_used) *num_fpstats_used = 0; + + // Search forward from the proposed arf/next gf position. + for (i = 0; i < f_frames; ++i) { + const FIRSTPASS_STATS *this_frame = read_frame_stats(twopass, i + offset); + if (this_frame == NULL) break; + + // Update the motion related elements to the boost calculation. + accumulate_frame_motion_stats(this_frame, &gf_stats); + + // We want to discount the flash frame itself and the recovery + // frame that follows as both will have poor scores. + flash_detected = detect_flash(twopass, i + offset) || + detect_flash(twopass, i + offset + 1); + + // Accumulate the effect of prediction quality decay. + if (!flash_detected) { + gf_stats.decay_accumulator *= + get_prediction_decay_rate(frame_info, this_frame); + gf_stats.decay_accumulator = gf_stats.decay_accumulator < MIN_DECAY_FACTOR + ? MIN_DECAY_FACTOR + : gf_stats.decay_accumulator; + } + + boost_score += + gf_stats.decay_accumulator * + calc_frame_boost(rc, frame_info, this_frame, + gf_stats.this_frame_mv_in_out, GF_MAX_BOOST); + if (num_fpstats_used) (*num_fpstats_used)++; + } + + arf_boost = (int)boost_score; + + // Reset for backward looking loop. + boost_score = 0.0; + init_gf_stats(&gf_stats); + // Search backward towards last gf position. + for (i = -1; i >= -b_frames; --i) { + const FIRSTPASS_STATS *this_frame = read_frame_stats(twopass, i + offset); + if (this_frame == NULL) break; + + // Update the motion related elements to the boost calculation. + accumulate_frame_motion_stats(this_frame, &gf_stats); + + // We want to discount the the flash frame itself and the recovery + // frame that follows as both will have poor scores. + flash_detected = detect_flash(twopass, i + offset) || + detect_flash(twopass, i + offset + 1); + + // Cumulative effect of prediction quality decay. + if (!flash_detected) { + gf_stats.decay_accumulator *= + get_prediction_decay_rate(frame_info, this_frame); + gf_stats.decay_accumulator = gf_stats.decay_accumulator < MIN_DECAY_FACTOR + ? MIN_DECAY_FACTOR + : gf_stats.decay_accumulator; + } + + boost_score += + gf_stats.decay_accumulator * + calc_frame_boost(rc, frame_info, this_frame, + gf_stats.this_frame_mv_in_out, GF_MAX_BOOST); + if (num_fpstats_used) (*num_fpstats_used)++; + } + arf_boost += (int)boost_score; + + if (num_fpstats_required) { + *num_fpstats_required = f_frames + b_frames; + if (num_fpstats_used) { + arf_boost = get_projected_gfu_boost(rc, arf_boost, *num_fpstats_required, + *num_fpstats_used); + } + } + + if (arf_boost < ((b_frames + f_frames) * 50)) + arf_boost = ((b_frames + f_frames) * 50); + + return arf_boost; +} + +// Calculate a section intra ratio used in setting max loop filter. +static int calculate_section_intra_ratio(const FIRSTPASS_STATS *begin, + const FIRSTPASS_STATS *end, + int section_length) { + const FIRSTPASS_STATS *s = begin; + double intra_error = 0.0; + double coded_error = 0.0; + int i = 0; + + while (s < end && i < section_length) { + intra_error += s->intra_error; + coded_error += s->coded_error; + ++s; + ++i; + } + + return (int)(intra_error / DOUBLE_DIVIDE_CHECK(coded_error)); +} + +// Calculate the total bits to allocate in this GF/ARF group. +static int64_t calculate_total_gf_group_bits(AV1_COMP *cpi, + double gf_group_err) { + const RATE_CONTROL *const rc = &cpi->rc; + const TWO_PASS *const twopass = &cpi->twopass; + const int max_bits = frame_max_bits(rc, &cpi->oxcf); + int64_t total_group_bits; + + // Calculate the bits to be allocated to the group as a whole. + if ((twopass->kf_group_bits > 0) && (twopass->kf_group_error_left > 0)) { + total_group_bits = (int64_t)(twopass->kf_group_bits * + (gf_group_err / twopass->kf_group_error_left)); + } else { + total_group_bits = 0; + } + + // Clamp odd edge cases. + total_group_bits = (total_group_bits < 0) + ? 0 + : (total_group_bits > twopass->kf_group_bits) + ? twopass->kf_group_bits + : total_group_bits; + + // Clip based on user supplied data rate variability limit. + if (total_group_bits > (int64_t)max_bits * rc->baseline_gf_interval) + total_group_bits = (int64_t)max_bits * rc->baseline_gf_interval; + + return total_group_bits; +} + +// Calculate the number of bits to assign to boosted frames in a group. +static int calculate_boost_bits(int frame_count, int boost, + int64_t total_group_bits) { + int allocation_chunks; + + // return 0 for invalid inputs (could arise e.g. through rounding errors) + if (!boost || (total_group_bits <= 0)) return 0; + + if (frame_count <= 0) return (int)(AOMMIN(total_group_bits, INT_MAX)); + + allocation_chunks = (frame_count * 100) + boost; + + // Prevent overflow. + if (boost > 1023) { + int divisor = boost >> 10; + boost /= divisor; + allocation_chunks /= divisor; + } + + // Calculate the number of extra bits for use in the boosted frame or frames. + return AOMMAX((int)(((int64_t)boost * total_group_bits) / allocation_chunks), + 0); +} + +// Calculate the boost factor based on the number of bits assigned, i.e. the +// inverse of calculate_boost_bits(). +static int calculate_boost_factor(int frame_count, int bits, + int64_t total_group_bits) { + aom_clear_system_state(); + return (int)(100.0 * frame_count * bits / (total_group_bits - bits)); +} + +// Reduce the number of bits assigned to keyframe or arf if necessary, to +// prevent bitrate spikes that may break level constraints. +// frame_type: 0: keyframe; 1: arf. +static int adjust_boost_bits_for_target_level(const AV1_COMP *const cpi, + RATE_CONTROL *const rc, + int bits_assigned, + int64_t group_bits, + int frame_type) { + const AV1_COMMON *const cm = &cpi->common; + const SequenceHeader *const seq_params = &cm->seq_params; + const int temporal_layer_id = cm->temporal_layer_id; + const int spatial_layer_id = cm->spatial_layer_id; + for (int index = 0; index < seq_params->operating_points_cnt_minus_1 + 1; + ++index) { + if (!is_in_operating_point(seq_params->operating_point_idc[index], + temporal_layer_id, spatial_layer_id)) { + continue; + } + + const AV1_LEVEL target_level = + cpi->level_params.target_seq_level_idx[index]; + if (target_level >= SEQ_LEVELS) continue; + + assert(is_valid_seq_level_idx(target_level)); + + const double level_bitrate_limit = av1_get_max_bitrate_for_level( + target_level, seq_params->tier[0], seq_params->profile); + const int target_bits_per_frame = + (int)(level_bitrate_limit / cpi->framerate); + if (frame_type == 0) { + // Maximum bits for keyframe is 8 times the target_bits_per_frame. + const int level_enforced_max_kf_bits = target_bits_per_frame * 8; + if (bits_assigned > level_enforced_max_kf_bits) { + const int frames = rc->frames_to_key - 1; + rc->kf_boost = calculate_boost_factor( + frames, level_enforced_max_kf_bits, group_bits); + bits_assigned = calculate_boost_bits(frames, rc->kf_boost, group_bits); + } + } else if (frame_type == 1) { + // Maximum bits for arf is 4 times the target_bits_per_frame. + const int level_enforced_max_arf_bits = target_bits_per_frame * 4; + if (bits_assigned > level_enforced_max_arf_bits) { + rc->gfu_boost = calculate_boost_factor( + rc->baseline_gf_interval, level_enforced_max_arf_bits, group_bits); + bits_assigned = calculate_boost_bits(rc->baseline_gf_interval, + rc->gfu_boost, group_bits); + } + } else { + assert(0); + } + } + + return bits_assigned; +} + +// Compile time switch on alternate algorithm to allocate bits in ARF groups +// #define ALT_ARF_ALLOCATION +#ifdef ALT_ARF_ALLOCATION +double layer_fraction[MAX_ARF_LAYERS + 1] = { 1.0, 0.70, 0.55, 0.60, + 0.60, 1.0, 1.0 }; +static void allocate_gf_group_bits(GF_GROUP *gf_group, RATE_CONTROL *const rc, + int64_t gf_group_bits, int gf_arf_bits, + int key_frame, int use_arf) { + int64_t total_group_bits = gf_group_bits; + int base_frame_bits; + const int gf_group_size = gf_group->size; + int layer_frames[MAX_ARF_LAYERS + 1] = { 0 }; + + // Subtract the extra bits set aside for ARF frames from the Group Total + if (use_arf || !key_frame) total_group_bits -= gf_arf_bits; + + if (rc->baseline_gf_interval) + base_frame_bits = (int)(total_group_bits / rc->baseline_gf_interval); + else + base_frame_bits = (int)1; + + // For key frames the frame target rate is already set and it + // is also the golden frame. + // === [frame_index == 0] === + int frame_index = 0; + if (!key_frame) { + if (rc->source_alt_ref_active) + gf_group->bit_allocation[frame_index] = 0; + else + gf_group->bit_allocation[frame_index] = + base_frame_bits + (int)(gf_arf_bits * layer_fraction[1]); + } + frame_index++; + + // Check the number of frames in each layer in case we have a + // non standard group length. + int max_arf_layer = gf_group->max_layer_depth - 1; + for (int idx = frame_index; idx < gf_group_size; ++idx) { + if ((gf_group->update_type[idx] == ARF_UPDATE) || + (gf_group->update_type[idx] == INTNL_ARF_UPDATE)) { + // max_arf_layer = AOMMAX(max_arf_layer, gf_group->layer_depth[idx]); + layer_frames[gf_group->layer_depth[idx]]++; + } + } + + // Allocate extra bits to each ARF layer + int i; + int layer_extra_bits[MAX_ARF_LAYERS + 1] = { 0 }; + for (i = 1; i <= max_arf_layer; ++i) { + double fraction = (i == max_arf_layer) ? 1.0 : layer_fraction[i]; + layer_extra_bits[i] = + (int)((gf_arf_bits * fraction) / AOMMAX(1, layer_frames[i])); + gf_arf_bits -= (int)(gf_arf_bits * fraction); + } + + // Now combine ARF layer and baseline bits to give total bits for each frame. + int arf_extra_bits; + for (int idx = frame_index; idx < gf_group_size; ++idx) { + switch (gf_group->update_type[idx]) { + case ARF_UPDATE: + case INTNL_ARF_UPDATE: + arf_extra_bits = layer_extra_bits[gf_group->layer_depth[idx]]; + gf_group->bit_allocation[idx] = base_frame_bits + arf_extra_bits; + break; + case INTNL_OVERLAY_UPDATE: + case OVERLAY_UPDATE: gf_group->bit_allocation[idx] = 0; break; + default: gf_group->bit_allocation[idx] = base_frame_bits; break; + } + } + + // Set the frame following the current GOP to 0 bit allocation. For ARF + // groups, this next frame will be overlay frame, which is the first frame + // in the next GOP. For GF group, next GOP will overwrite the rate allocation. + // Setting this frame to use 0 bit (of out the current GOP budget) will + // simplify logics in reference frame management. + gf_group->bit_allocation[gf_group_size] = 0; +} +#else +static void allocate_gf_group_bits(GF_GROUP *gf_group, RATE_CONTROL *const rc, + int64_t gf_group_bits, int gf_arf_bits, + int key_frame, int use_arf) { + int64_t total_group_bits = gf_group_bits; + + // For key frames the frame target rate is already set and it + // is also the golden frame. + // === [frame_index == 0] === + int frame_index = 0; + if (!key_frame) { + if (rc->source_alt_ref_active) + gf_group->bit_allocation[frame_index] = 0; + else + gf_group->bit_allocation[frame_index] = gf_arf_bits; + } + + // Deduct the boost bits for arf (or gf if it is not a key frame) + // from the group total. + if (use_arf || !key_frame) total_group_bits -= gf_arf_bits; + + frame_index++; + + // Store the bits to spend on the ARF if there is one. + // === [frame_index == 1] === + if (use_arf) { + gf_group->bit_allocation[frame_index] = gf_arf_bits; + ++frame_index; + } + + const int gf_group_size = gf_group->size; + int arf_depth_bits[MAX_ARF_LAYERS + 1] = { 0 }; + int arf_depth_count[MAX_ARF_LAYERS + 1] = { 0 }; + int arf_depth_boost[MAX_ARF_LAYERS + 1] = { 0 }; + int total_arfs = 0; + int total_overlays = rc->source_alt_ref_active; + + for (int idx = 0; idx < gf_group_size; ++idx) { + if (gf_group->update_type[idx] == ARF_UPDATE || + gf_group->update_type[idx] == INTNL_ARF_UPDATE || + gf_group->update_type[idx] == LF_UPDATE) { + arf_depth_boost[gf_group->layer_depth[idx]] += gf_group->arf_boost[idx]; + ++arf_depth_count[gf_group->layer_depth[idx]]; + } + } + + for (int idx = 2; idx <= MAX_ARF_LAYERS; ++idx) { + arf_depth_bits[idx] = + calculate_boost_bits(rc->baseline_gf_interval - total_arfs - + total_overlays - arf_depth_count[idx], + arf_depth_boost[idx], total_group_bits); + total_group_bits -= arf_depth_bits[idx]; + total_arfs += arf_depth_count[idx]; + } + + for (int idx = frame_index; idx < gf_group_size; ++idx) { + switch (gf_group->update_type[idx]) { + case ARF_UPDATE: + case INTNL_ARF_UPDATE: + case LF_UPDATE: + gf_group->bit_allocation[idx] = + (int)(((int64_t)arf_depth_bits[gf_group->layer_depth[idx]] * + gf_group->arf_boost[idx]) / + arf_depth_boost[gf_group->layer_depth[idx]]); + break; + case INTNL_OVERLAY_UPDATE: + case OVERLAY_UPDATE: + default: gf_group->bit_allocation[idx] = 0; break; + } + } + + // Set the frame following the current GOP to 0 bit allocation. For ARF + // groups, this next frame will be overlay frame, which is the first frame + // in the next GOP. For GF group, next GOP will overwrite the rate allocation. + // Setting this frame to use 0 bit (of out the current GOP budget) will + // simplify logics in reference frame management. + gf_group->bit_allocation[gf_group_size] = 0; +} +#endif + +// Returns true if KF group and GF group both are almost completely static. +static INLINE int is_almost_static(double gf_zero_motion, int kf_zero_motion) { + return (gf_zero_motion >= 0.995) && + (kf_zero_motion >= STATIC_KF_GROUP_THRESH); +} + +#define ARF_ABS_ZOOM_THRESH 4.4 +static INLINE int detect_gf_cut(AV1_COMP *cpi, int frame_index, int cur_start, + int flash_detected, int active_max_gf_interval, + int active_min_gf_interval, + GF_GROUP_STATS *gf_stats) { + RATE_CONTROL *const rc = &cpi->rc; + TWO_PASS *const twopass = &cpi->twopass; + // Motion breakout threshold for loop below depends on image size. + const double mv_ratio_accumulator_thresh = + (cpi->initial_height + cpi->initial_width) / 4.0; + + if (!flash_detected) { + // Break clause to detect very still sections after motion. For example, + // a static image after a fade or other transition. + if (detect_transition_to_still( + twopass, rc->min_gf_interval, frame_index - cur_start, 5, + gf_stats->loop_decay_rate, gf_stats->last_loop_decay_rate)) { + return 1; + } + } + + // Some conditions to breakout after min interval. + if (frame_index - cur_start >= active_min_gf_interval && + // If possible don't break very close to a kf + (rc->frames_to_key - frame_index >= rc->min_gf_interval) && + ((frame_index - cur_start) & 0x01) && !flash_detected && + (gf_stats->mv_ratio_accumulator > mv_ratio_accumulator_thresh || + gf_stats->abs_mv_in_out_accumulator > ARF_ABS_ZOOM_THRESH)) { + return 1; + } + + // If almost totally static, we will not use the the max GF length later, + // so we can continue for more frames. + if (((frame_index - cur_start) >= active_max_gf_interval + 1) && + !is_almost_static(gf_stats->zero_motion_accumulator, + twopass->kf_zeromotion_pct)) { + return 1; + } + return 0; +} + +#define MAX_PAD_GF_CHECK 6 // padding length to check for gf length +#define AVG_SI_THRES 0.6 // thres for average silouette +#define GF_SHRINK_OUTPUT 0 // print output for gf length decision +int determine_high_err_gf(double *errs, int *is_high, double *si, int len, + double *ratio, int gf_start, int gf_end, + int before_pad) { + (void)gf_start; + (void)gf_end; + (void)before_pad; + // alpha and beta controls the threshold placement + // e.g. a smaller alpha makes the lower group more rigid + const double alpha = 0.5; + const double beta = 1 - alpha; + double mean = 0; + double mean_low = 0; + double mean_high = 0; + double prev_mean_low = 0; + double prev_mean_high = 0; + int count_low = 0; + int count_high = 0; + // calculate mean of errs + for (int i = 0; i < len; i++) { + mean += errs[i]; + } + mean /= len; + // separate into two initial groups with greater / lower than mean + for (int i = 0; i < len; i++) { + if (errs[i] <= mean) { + is_high[i] = 0; + count_low++; + prev_mean_low += errs[i]; + } else { + is_high[i] = 1; + count_high++; + prev_mean_high += errs[i]; + } + } + prev_mean_low /= count_low; + prev_mean_high /= count_high; + // kmeans to refine + int count = 0; + while (count < 10) { + // re-group + mean_low = 0; + mean_high = 0; + count_low = 0; + count_high = 0; + double thres = prev_mean_low * alpha + prev_mean_high * beta; + for (int i = 0; i < len; i++) { + if (errs[i] <= thres) { + is_high[i] = 0; + count_low++; + mean_low += errs[i]; + } else { + is_high[i] = 1; + count_high++; + mean_high += errs[i]; + } + } + mean_low /= count_low; + mean_high /= count_high; + + // break if not changed much + if (fabs((mean_low - prev_mean_low) / (prev_mean_low + 0.00001)) < + 0.00001 && + fabs((mean_high - prev_mean_high) / (prev_mean_high + 0.00001)) < + 0.00001) + break; + + // update means + prev_mean_high = mean_high; + prev_mean_low = mean_low; + + count++; + } + + // count how many jumps of group changes + int num_change = 0; + for (int i = 0; i < len - 1; i++) { + if (is_high[i] != is_high[i + 1]) num_change++; + } + + // get silhouette as a measure of the classification quality + double avg_si = 0; + // ai: avg dist of its own class, bi: avg dist to the other class + double ai, bi; + if (count_low > 1 && count_high > 1) { + for (int i = 0; i < len; i++) { + ai = 0; + bi = 0; + // calculate average distance to everyone in the same group + // and in the other group + for (int j = 0; j < len; j++) { + if (i == j) continue; + if (is_high[i] == is_high[j]) { + ai += fabs(errs[i] - errs[j]); + } else { + bi += fabs(errs[i] - errs[j]); + } + } + if (is_high[i] == 0) { + ai = ai / (count_low - 1); + bi = bi / count_high; + } else { + ai = ai / (count_high - 1); + bi = bi / count_low; + } + if (ai <= bi) { + si[i] = 1 - ai / (bi + 0.00001); + } else { + si[i] = bi / (ai + 0.00001) - 1; + } + avg_si += si[i]; + } + avg_si /= len; + } + + int reset = 0; + *ratio = mean_high / (mean_low + 0.00001); + // if the two groups too similar, or + // if too many numbers of changes, or + // silhouette is too small, not confident + // reset everything to 0 later so we fallback to the original decision + if (*ratio < 1.3 || num_change > AOMMAX(len / 3, 6) || + avg_si < AVG_SI_THRES) { + reset = 1; + } + +#if GF_SHRINK_OUTPUT + printf("\n"); + for (int i = 0; i < len; i++) { + printf("%d: err %.1f, ishigh %d, si %.2f, (i=%d)\n", + gf_start + i - before_pad, errs[i], is_high[i], si[i], gf_end); + } + printf( + "count: %d, mean_high: %.1f, mean_low: %.1f, avg_si: %.2f, num_change: " + "%d, ratio %.2f, reset: %d\n", + count, mean_high, mean_low, avg_si, num_change, + mean_high / (mean_low + 0.000001), reset); +#endif + + if (reset) { + memset(is_high, 0, sizeof(is_high[0]) * len); + memset(si, 0, sizeof(si[0]) * len); + } + return reset; +} + +#if GROUP_ADAPTIVE_MAXQ +#define RC_FACTOR_MIN 0.75 +#define RC_FACTOR_MAX 1.25 +#endif // GROUP_ADAPTIVE_MAXQ +#define MIN_FWD_KF_INTERVAL 8 +#define MIN_SHRINK_LEN 6 // the minimum length of gf if we are shrinking +#define SI_HIGH AVG_SI_THRES // high quality classification +#define SI_LOW 0.3 // very unsure classification +// this function finds an low error frame previously to the current last frame +// in the gf group, and set the last frame to it. +// The resulting last frame is then returned by *cur_last_ptr +// *cur_start_ptr and cut_pos[n] could also change due to shrinking +// previous gf groups +void set_last_prev_low_err(int *cur_start_ptr, int *cur_last_ptr, int *cut_pos, + int count_cuts, int before_pad, double ratio, + int *is_high, double *si, int prev_lows) { + int n; + int cur_start = *cur_start_ptr; + int cur_last = *cur_last_ptr; + for (n = cur_last; n >= cur_start + MIN_SHRINK_LEN; n--) { + // try to find a point that is very probable to be good + if (is_high[n - cur_start + before_pad] == 0 && + si[n - cur_start + before_pad] > SI_HIGH) { + *cur_last_ptr = n; + return; + } + } + // could not find a low-err point, then let's try find an "unsure" + // point at least + for (n = cur_last; n >= cur_start + MIN_SHRINK_LEN; n--) { + if ((is_high[n - cur_start + before_pad] == 0) || + (is_high[n - cur_start + before_pad] && + si[n - cur_start + before_pad] < SI_LOW)) { + *cur_last_ptr = n; + return; + } + } + if (prev_lows) { + // try with shrinking previous all_zero interval + for (n = cur_start + MIN_SHRINK_LEN - 1; n > cur_start; n--) { + if (is_high[n - cur_start + before_pad] == 0 && + si[n - cur_start + before_pad] > SI_HIGH) { + int tentative_start = n - MIN_SHRINK_LEN; + // check if the previous interval can shrink this much + int available = + tentative_start - cut_pos[count_cuts - 2] > MIN_SHRINK_LEN && + cur_start - tentative_start < prev_lows; + // shrinking too agressively may worsen performance + // set stricter thres for shorter length + double ratio_thres = + 1.0 * (cur_start - tentative_start) / (double)(MIN_SHRINK_LEN) + + 1.0; + + if (available && (ratio > ratio_thres)) { + cut_pos[count_cuts - 1] = tentative_start; + *cur_start_ptr = tentative_start; + *cur_last_ptr = n; + return; + } + } + } + } + if (prev_lows) { + // try with shrinking previous all_zero interval with unsure points + for (n = cur_start + MIN_SHRINK_LEN - 1; n > cur_start; n--) { + if ((is_high[n - cur_start + before_pad] == 0) || + (is_high[n - cur_start + before_pad] && + si[n - cur_start + before_pad] < SI_LOW)) { + int tentative_start = n - MIN_SHRINK_LEN; + // check if the previous interval can shrink this much + int available = + tentative_start - cut_pos[count_cuts - 2] > MIN_SHRINK_LEN && + cur_start - tentative_start < prev_lows; + // shrinking too agressively may worsen performance + double ratio_thres = + 1.0 * (cur_start - tentative_start) / (double)(MIN_SHRINK_LEN) + + 1.0; + + if (available && (ratio > ratio_thres)) { + cut_pos[count_cuts - 1] = tentative_start; + *cur_start_ptr = tentative_start; + *cur_last_ptr = n; + return; + } + } + } + } // prev_lows + return; +} + +// This function decides the gf group length of future frames in batch +// rc->gf_intervals is modified to store the group lengths +static void calculate_gf_length(AV1_COMP *cpi, int max_gop_length, + int max_intervals) { + RATE_CONTROL *const rc = &cpi->rc; + TWO_PASS *const twopass = &cpi->twopass; + FIRSTPASS_STATS next_frame; + const FIRSTPASS_STATS *const start_pos = twopass->stats_in; + FRAME_INFO *frame_info = &cpi->frame_info; + int i; + + int flash_detected; + + aom_clear_system_state(); + av1_zero(next_frame); + + if (has_no_stats_stage(cpi)) { + for (i = 0; i < MAX_NUM_GF_INTERVALS; i++) { + rc->gf_intervals[i] = AOMMIN(rc->max_gf_interval, max_gop_length); + } + rc->cur_gf_index = 0; + rc->intervals_till_gf_calculate_due = MAX_NUM_GF_INTERVALS; + return; + } + + // TODO(urvang): Try logic to vary min and max interval based on q. + const int active_min_gf_interval = rc->min_gf_interval; + const int active_max_gf_interval = + AOMMIN(rc->max_gf_interval, max_gop_length); + + i = 0; + max_intervals = cpi->lap_enabled ? 1 : max_intervals; + int cut_pos[MAX_NUM_GF_INTERVALS + 1] = { 0 }; + int count_cuts = 1; + int cur_start = 0, cur_last; + int cut_here; + int prev_lows = 0; + GF_GROUP_STATS gf_stats; + init_gf_stats(&gf_stats); + while (count_cuts < max_intervals + 1) { + ++i; + + // reaches next key frame, break here + if (i >= rc->frames_to_key) { + cut_pos[count_cuts] = i - 1; + count_cuts++; + break; + } + + // reached maximum len, but nothing special yet (almost static) + // let's look at the next interval + if (i - cur_start >= rc->static_scene_max_gf_interval) { + cut_here = 1; + } else { + // reaches last frame, break + if (EOF == input_stats(twopass, &next_frame)) { + cut_pos[count_cuts] = i - 1; + count_cuts++; + break; + } + // Test for the case where there is a brief flash but the prediction + // quality back to an earlier frame is then restored. + flash_detected = detect_flash(twopass, 0); + // TODO(bohanli): remove redundant accumulations here, or unify + // this and the ones in define_gf_group + accumulate_next_frame_stats(&next_frame, frame_info, twopass, + flash_detected, rc->frames_since_key, i, 0, + rc->min_gf_interval, &gf_stats); + + cut_here = detect_gf_cut(cpi, i, cur_start, flash_detected, + active_max_gf_interval, active_min_gf_interval, + &gf_stats); + } + if (cut_here) { + cur_last = i - 1; // the current last frame in the gf group + // only try shrinking if interval smaller than active_max_gf_interval + if (cur_last - cur_start <= active_max_gf_interval) { + // determine in the current decided gop the higher and lower errs + int n; + double ratio; + + // load neighboring coded errs + int is_high[MAX_GF_INTERVAL + 1 + MAX_PAD_GF_CHECK * 2] = { 0 }; + double errs[MAX_GF_INTERVAL + 1 + MAX_PAD_GF_CHECK * 2] = { 0 }; + double si[MAX_GF_INTERVAL + 1 + MAX_PAD_GF_CHECK * 2] = { 0 }; + int before_pad = + AOMMIN(MAX_PAD_GF_CHECK, rc->frames_since_key - 1 + cur_start); + int after_pad = + AOMMIN(MAX_PAD_GF_CHECK, rc->frames_to_key - cur_last - 1); + for (n = cur_start - before_pad; n <= cur_last + after_pad; n++) { + if (start_pos + n - 1 > twopass->stats_buf_ctx->stats_in_end) { + after_pad = n - cur_last - 1; + assert(after_pad >= 0); + break; + } else if (start_pos + n - 1 < + twopass->stats_buf_ctx->stats_in_start) { + before_pad = cur_start - n - 1; + continue; + } + errs[n + before_pad - cur_start] = (start_pos + n - 1)->coded_error; + } + const int len = before_pad + after_pad + cur_last - cur_start + 1; + const int reset = determine_high_err_gf( + errs, is_high, si, len, &ratio, cur_start, cur_last, before_pad); + + // if the current frame may have high error, try shrinking + if (is_high[cur_last - cur_start + before_pad] == 1 || + (!reset && si[cur_last - cur_start + before_pad] < SI_LOW)) { + // try not to cut in high err area + set_last_prev_low_err(&cur_start, &cur_last, cut_pos, count_cuts, + before_pad, ratio, is_high, si, prev_lows); + } // if current frame high error + // count how many trailing lower error frames we have in this decided + // gf group + prev_lows = 0; + for (n = cur_last - 1; n > cur_start + MIN_SHRINK_LEN; n--) { + if (is_high[n - cur_start + before_pad] == 0 && + (si[n - cur_start + before_pad] > SI_HIGH || reset)) { + prev_lows++; + } else { + break; + } + } + } + cut_pos[count_cuts] = cur_last; + count_cuts++; + + // reset pointers to the shrinked location + twopass->stats_in = start_pos + cur_last; + cur_start = cur_last; + i = cur_last; + + // reset accumulators + init_gf_stats(&gf_stats); + } + } + + // save intervals + rc->intervals_till_gf_calculate_due = count_cuts - 1; + for (int n = 1; n < count_cuts; n++) { + rc->gf_intervals[n - 1] = cut_pos[n] + 1 - cut_pos[n - 1]; + } + rc->cur_gf_index = 0; + twopass->stats_in = start_pos; + +#if GF_SHRINK_OUTPUT + printf("\nf_to_key: %d, count_cut: %d. ", rc->frames_to_key, count_cuts); + for (int n = 0; n < count_cuts; n++) { + printf("%d ", cut_pos[n]); + } + printf("\n"); + + for (int n = 0; n < rc->intervals_till_gf_calculate_due; n++) { + printf("%d ", rc->gf_intervals[n]); + } + printf("\n\n"); +#endif +} + +static void correct_frames_to_key(AV1_COMP *cpi) { + int lookahead_size = + (int)av1_lookahead_depth(cpi->lookahead, cpi->compressor_stage) + 1; + if (lookahead_size < + av1_lookahead_pop_sz(cpi->lookahead, cpi->compressor_stage)) { + cpi->rc.frames_to_key = AOMMIN(cpi->rc.frames_to_key, lookahead_size); + } +} + +static void define_gf_group_pass0(AV1_COMP *cpi, + const EncodeFrameParams *const frame_params) { + RATE_CONTROL *const rc = &cpi->rc; + GF_GROUP *const gf_group = &cpi->gf_group; + int target; + + if (cpi->oxcf.aq_mode == CYCLIC_REFRESH_AQ) { + av1_cyclic_refresh_set_golden_update(cpi); + } else { + rc->baseline_gf_interval = rc->gf_intervals[rc->cur_gf_index]; + rc->intervals_till_gf_calculate_due--; + rc->cur_gf_index++; + } + + // correct frames_to_key when lookahead queue is flushing + correct_frames_to_key(cpi); + + if (rc->baseline_gf_interval > rc->frames_to_key) + rc->baseline_gf_interval = rc->frames_to_key; + + rc->gfu_boost = DEFAULT_GF_BOOST; + rc->constrained_gf_group = + (rc->baseline_gf_interval >= rc->frames_to_key) ? 1 : 0; + + gf_group->max_layer_depth_allowed = cpi->oxcf.gf_max_pyr_height; + + // Rare case when the look-ahead is less than the target GOP length, can't + // generate ARF frame. + if (rc->baseline_gf_interval > cpi->oxcf.lag_in_frames || + !is_altref_enabled(cpi) || rc->baseline_gf_interval < rc->min_gf_interval) + gf_group->max_layer_depth_allowed = 0; + + // Set up the structure of this Group-Of-Pictures (same as GF_GROUP) + av1_gop_setup_structure(cpi, frame_params); + + // Allocate bits to each of the frames in the GF group. + // TODO(sarahparker) Extend this to work with pyramid structure. + for (int cur_index = 0; cur_index < gf_group->size; ++cur_index) { + const FRAME_UPDATE_TYPE cur_update_type = gf_group->update_type[cur_index]; + if (cpi->oxcf.rc_mode == AOM_CBR) { + if (cur_update_type == KEY_FRAME) { + target = av1_calc_iframe_target_size_one_pass_cbr(cpi); + } else { + target = av1_calc_pframe_target_size_one_pass_cbr(cpi, cur_update_type); + } + } else { + if (cur_update_type == KEY_FRAME) { + target = av1_calc_iframe_target_size_one_pass_vbr(cpi); + } else { + target = av1_calc_pframe_target_size_one_pass_vbr(cpi, cur_update_type); + } + } + gf_group->bit_allocation[cur_index] = target; + } +} + +static INLINE void set_baseline_gf_interval(AV1_COMP *cpi, int arf_position, + int active_max_gf_interval, + int use_alt_ref, + int is_final_pass) { + RATE_CONTROL *const rc = &cpi->rc; + TWO_PASS *const twopass = &cpi->twopass; + // Set the interval until the next gf. + // If forward keyframes are enabled, ensure the final gf group obeys the + // MIN_FWD_KF_INTERVAL. + if (cpi->oxcf.fwd_kf_enabled && use_alt_ref && + ((twopass->stats_in - arf_position + rc->frames_to_key) < + twopass->stats_buf_ctx->stats_in_end) && + cpi->rc.next_is_fwd_key) { + if (arf_position == rc->frames_to_key) { + rc->baseline_gf_interval = arf_position; + // if the last gf group will be smaller than MIN_FWD_KF_INTERVAL + } else if ((rc->frames_to_key - arf_position < + AOMMAX(MIN_FWD_KF_INTERVAL, rc->min_gf_interval)) && + (rc->frames_to_key != arf_position)) { + // if possible, merge the last two gf groups + if (rc->frames_to_key <= active_max_gf_interval) { + rc->baseline_gf_interval = rc->frames_to_key; + if (is_final_pass) rc->intervals_till_gf_calculate_due = 0; + // if merging the last two gf groups creates a group that is too long, + // split them and force the last gf group to be the MIN_FWD_KF_INTERVAL + } else { + rc->baseline_gf_interval = rc->frames_to_key - MIN_FWD_KF_INTERVAL; + if (is_final_pass) rc->intervals_till_gf_calculate_due = 0; + } + } else { + rc->baseline_gf_interval = arf_position - rc->source_alt_ref_pending; + } + } else { + rc->baseline_gf_interval = arf_position - rc->source_alt_ref_pending; + } +} + +// initialize GF_GROUP_STATS +static void init_gf_stats(GF_GROUP_STATS *gf_stats) { + gf_stats->gf_group_err = 0.0; + gf_stats->gf_group_raw_error = 0.0; + gf_stats->gf_group_skip_pct = 0.0; + gf_stats->gf_group_inactive_zone_rows = 0.0; + + gf_stats->mv_ratio_accumulator = 0.0; + gf_stats->decay_accumulator = 1.0; + gf_stats->zero_motion_accumulator = 1.0; + gf_stats->loop_decay_rate = 1.0; + gf_stats->last_loop_decay_rate = 1.0; + gf_stats->this_frame_mv_in_out = 0.0; + gf_stats->mv_in_out_accumulator = 0.0; + gf_stats->abs_mv_in_out_accumulator = 0.0; + + gf_stats->avg_sr_coded_error = 0.0; + gf_stats->avg_tr_coded_error = 0.0; + gf_stats->avg_pcnt_second_ref = 0.0; + gf_stats->avg_pcnt_third_ref = 0.0; + gf_stats->avg_pcnt_third_ref_nolast = 0.0; + gf_stats->avg_new_mv_count = 0.0; + gf_stats->avg_wavelet_energy = 0.0; + gf_stats->avg_raw_err_stdev = 0.0; + gf_stats->non_zero_stdev_count = 0; + + gf_stats->allow_alt_ref = 0; +} + +// Analyse and define a gf/arf group. +#define MAX_GF_BOOST 5400 +static void define_gf_group(AV1_COMP *cpi, FIRSTPASS_STATS *this_frame, + const EncodeFrameParams *const frame_params, + int max_gop_length, int is_final_pass) { + AV1_COMMON *const cm = &cpi->common; + RATE_CONTROL *const rc = &cpi->rc; + AV1EncoderConfig *const oxcf = &cpi->oxcf; + TWO_PASS *const twopass = &cpi->twopass; + FIRSTPASS_STATS next_frame; + const FIRSTPASS_STATS *const start_pos = twopass->stats_in; + GF_GROUP *gf_group = &cpi->gf_group; + FRAME_INFO *frame_info = &cpi->frame_info; + int i; + + int flash_detected; + int64_t gf_group_bits; + const int is_intra_only = frame_params->frame_type == KEY_FRAME || + frame_params->frame_type == INTRA_ONLY_FRAME; + const int arf_active_or_kf = is_intra_only || rc->source_alt_ref_active; + + cpi->internal_altref_allowed = (oxcf->gf_max_pyr_height > 1); + + // Reset the GF group data structures unless this is a key + // frame in which case it will already have been done. + if (!is_intra_only) { + av1_zero(cpi->gf_group); + } + + aom_clear_system_state(); + av1_zero(next_frame); + + if (has_no_stats_stage(cpi)) { + define_gf_group_pass0(cpi, frame_params); + return; + } + + // correct frames_to_key when lookahead queue is emptying + if (cpi->lap_enabled) { + correct_frames_to_key(cpi); + } + + GF_GROUP_STATS gf_stats; + init_gf_stats(&gf_stats); + GF_FRAME_STATS first_frame_stats, last_frame_stats; + + gf_stats.allow_alt_ref = is_altref_enabled(cpi); + const int can_disable_arf = (oxcf->gf_min_pyr_height == MIN_PYRAMID_LVL); + + // Load stats for the current frame. + double mod_frame_err = + calculate_modified_err(frame_info, twopass, oxcf, this_frame); + + // Note the error of the frame at the start of the group. This will be + // the GF frame error if we code a normal gf. + first_frame_stats.frame_err = mod_frame_err; + first_frame_stats.frame_coded_error = this_frame->coded_error; + first_frame_stats.frame_sr_coded_error = this_frame->sr_coded_error; + first_frame_stats.frame_tr_coded_error = this_frame->tr_coded_error; + + // If this is a key frame or the overlay from a previous arf then + // the error score / cost of this frame has already been accounted for. + if (arf_active_or_kf) { + gf_stats.gf_group_err -= first_frame_stats.frame_err; +#if GROUP_ADAPTIVE_MAXQ + gf_stats.gf_group_raw_error -= this_frame->coded_error; +#endif + gf_stats.gf_group_skip_pct -= this_frame->intra_skip_pct; + gf_stats.gf_group_inactive_zone_rows -= this_frame->inactive_zone_rows; + } + + // TODO(urvang): Try logic to vary min and max interval based on q. + const int active_min_gf_interval = rc->min_gf_interval; + const int active_max_gf_interval = + AOMMIN(rc->max_gf_interval, max_gop_length); + + i = 0; + // get the determined gf group length from rc->gf_intervals + while (i < rc->gf_intervals[rc->cur_gf_index]) { + ++i; + // Accumulate error score of frames in this gf group. + mod_frame_err = + calculate_modified_err(frame_info, twopass, oxcf, this_frame); + // accumulate stats for this frame + accumulate_this_frame_stats(this_frame, mod_frame_err, &gf_stats); + + // read in the next frame + if (EOF == input_stats(twopass, &next_frame)) break; + + // Test for the case where there is a brief flash but the prediction + // quality back to an earlier frame is then restored. + flash_detected = detect_flash(twopass, 0); + + // accumulate stats for next frame + accumulate_next_frame_stats( + &next_frame, frame_info, twopass, flash_detected, rc->frames_since_key, + i, can_disable_arf, rc->min_gf_interval, &gf_stats); + + *this_frame = next_frame; + } + // save the errs for the last frame + last_frame_stats.frame_coded_error = next_frame.coded_error; + last_frame_stats.frame_sr_coded_error = next_frame.sr_coded_error; + last_frame_stats.frame_tr_coded_error = next_frame.tr_coded_error; + + if (is_final_pass) { + rc->intervals_till_gf_calculate_due--; + rc->cur_gf_index++; + } + + // Was the group length constrained by the requirement for a new KF? + rc->constrained_gf_group = (i >= rc->frames_to_key) ? 1 : 0; + + const int num_mbs = (cpi->oxcf.resize_mode != RESIZE_NONE) + ? cpi->initial_mbs + : cm->mi_params.MBs; + assert(num_mbs > 0); + + average_gf_stats(i, &next_frame, &gf_stats); + + // Disable internal ARFs for "still" gf groups. + // zero_motion_accumulator: minimum percentage of (0,0) motion; + // avg_sr_coded_error: average of the SSE per pixel of each frame; + // avg_raw_err_stdev: average of the standard deviation of (0,0) + // motion error per block of each frame. + const int can_disable_internal_arfs = + (oxcf->gf_min_pyr_height <= MIN_PYRAMID_LVL + 1); + if (can_disable_internal_arfs && + gf_stats.zero_motion_accumulator > MIN_ZERO_MOTION && + gf_stats.avg_sr_coded_error / num_mbs < MAX_SR_CODED_ERROR && + gf_stats.avg_raw_err_stdev < MAX_RAW_ERR_VAR) { + cpi->internal_altref_allowed = 0; + } + + int use_alt_ref; + if (can_disable_arf) { + use_alt_ref = !is_almost_static(gf_stats.zero_motion_accumulator, + twopass->kf_zeromotion_pct) && + gf_stats.allow_alt_ref && (i < cpi->oxcf.lag_in_frames) && + (i >= MIN_GF_INTERVAL) && + (cpi->oxcf.gf_max_pyr_height > MIN_PYRAMID_LVL); + + // TODO(urvang): Improve and use model for VBR, CQ etc as well. + if (use_alt_ref && cpi->oxcf.rc_mode == AOM_Q && + cpi->oxcf.cq_level <= 200) { + aom_clear_system_state(); + float features[21]; + get_features_from_gf_stats( + &gf_stats, &first_frame_stats, &last_frame_stats, num_mbs, + rc->constrained_gf_group, twopass->kf_zeromotion_pct, i, features); + // Infer using ML model. + float score; + av1_nn_predict(features, &av1_use_flat_gop_nn_config, 1, &score); + use_alt_ref = (score <= 0.0); + } + } else { + assert(cpi->oxcf.gf_max_pyr_height > MIN_PYRAMID_LVL); + use_alt_ref = + gf_stats.allow_alt_ref && (i < cpi->oxcf.lag_in_frames) && (i > 2); + } + +#define REDUCE_GF_LENGTH_THRESH 4 +#define REDUCE_GF_LENGTH_TO_KEY_THRESH 9 +#define REDUCE_GF_LENGTH_BY 1 + int alt_offset = 0; + // The length reduction strategy is tweaked for certain cases, and doesn't + // work well for certain other cases. + const int allow_gf_length_reduction = + ((cpi->oxcf.rc_mode == AOM_Q && cpi->oxcf.cq_level <= 128) || + !cpi->internal_altref_allowed) && + !is_lossless_requested(&cpi->oxcf); + + if (allow_gf_length_reduction && use_alt_ref) { + // adjust length of this gf group if one of the following condition met + // 1: only one overlay frame left and this gf is too long + // 2: next gf group is too short to have arf compared to the current gf + + // maximum length of next gf group + const int next_gf_len = rc->frames_to_key - i; + const int single_overlay_left = + next_gf_len == 0 && i > REDUCE_GF_LENGTH_THRESH; + // the next gf is probably going to have a ARF but it will be shorter than + // this gf + const int unbalanced_gf = + i > REDUCE_GF_LENGTH_TO_KEY_THRESH && + next_gf_len + 1 < REDUCE_GF_LENGTH_TO_KEY_THRESH && + next_gf_len + 1 >= rc->min_gf_interval; + + if (single_overlay_left || unbalanced_gf) { + const int roll_back = REDUCE_GF_LENGTH_BY; + // Reduce length only if active_min_gf_interval will be respected later. + if (i - roll_back >= active_min_gf_interval + 1) { + alt_offset = -roll_back; + i -= roll_back; + if (is_final_pass) rc->intervals_till_gf_calculate_due = 0; + } + } + } + + // Should we use the alternate reference frame. + if (use_alt_ref) { + rc->source_alt_ref_pending = 1; + gf_group->max_layer_depth_allowed = cpi->oxcf.gf_max_pyr_height; + set_baseline_gf_interval(cpi, i, active_max_gf_interval, use_alt_ref, + is_final_pass); + + const int forward_frames = (rc->frames_to_key - i >= i - 1) + ? i - 1 + : AOMMAX(0, rc->frames_to_key - i); + + // Calculate the boost for alt ref. + rc->gfu_boost = av1_calc_arf_boost( + twopass, rc, frame_info, alt_offset, forward_frames, (i - 1), + cpi->lap_enabled ? &rc->num_stats_used_for_gfu_boost : NULL, + cpi->lap_enabled ? &rc->num_stats_required_for_gfu_boost : NULL); + } else { + reset_fpf_position(twopass, start_pos); + rc->source_alt_ref_pending = 0; + gf_group->max_layer_depth_allowed = 0; + set_baseline_gf_interval(cpi, i, active_max_gf_interval, use_alt_ref, + is_final_pass); + + rc->gfu_boost = AOMMIN( + MAX_GF_BOOST, + av1_calc_arf_boost( + twopass, rc, frame_info, alt_offset, (i - 1), 0, + cpi->lap_enabled ? &rc->num_stats_used_for_gfu_boost : NULL, + cpi->lap_enabled ? &rc->num_stats_required_for_gfu_boost : NULL)); + } + + // rc->gf_intervals assumes the usage of alt_ref, therefore adding one overlay + // frame to the next gf. If no alt_ref is used, should substract 1 frame from + // the next gf group. + // TODO(bohanli): should incorporate the usage of alt_ref into + // calculate_gf_length + if (is_final_pass && rc->source_alt_ref_pending == 0 && + rc->intervals_till_gf_calculate_due > 0) { + rc->gf_intervals[rc->cur_gf_index]--; + } + +#define LAST_ALR_BOOST_FACTOR 0.2f + rc->arf_boost_factor = 1.0; + if (rc->source_alt_ref_pending && !is_lossless_requested(&cpi->oxcf)) { + // Reduce the boost of altref in the last gf group + if (rc->frames_to_key - i == REDUCE_GF_LENGTH_BY || + rc->frames_to_key - i == 0) { + rc->arf_boost_factor = LAST_ALR_BOOST_FACTOR; + } + } + + rc->frames_till_gf_update_due = rc->baseline_gf_interval; + + // Reset the file position. + reset_fpf_position(twopass, start_pos); + + // Calculate the bits to be allocated to the gf/arf group as a whole + gf_group_bits = calculate_total_gf_group_bits(cpi, gf_stats.gf_group_err); + rc->gf_group_bits = gf_group_bits; + +#if GROUP_ADAPTIVE_MAXQ + // Calculate an estimate of the maxq needed for the group. + // We are more agressive about correcting for sections + // where there could be significant overshoot than for easier + // sections where we do not wish to risk creating an overshoot + // of the allocated bit budget. + if ((cpi->oxcf.rc_mode != AOM_Q) && (rc->baseline_gf_interval > 1)) { + const int vbr_group_bits_per_frame = + (int)(gf_group_bits / rc->baseline_gf_interval); + const double group_av_err = + gf_stats.gf_group_raw_error / rc->baseline_gf_interval; + const double group_av_skip_pct = + gf_stats.gf_group_skip_pct / rc->baseline_gf_interval; + const double group_av_inactive_zone = + ((gf_stats.gf_group_inactive_zone_rows * 2) / + (rc->baseline_gf_interval * (double)cm->mi_params.mb_rows)); + + int tmp_q; + // rc factor is a weight factor that corrects for local rate control drift. + double rc_factor = 1.0; + int64_t bits = cpi->oxcf.target_bandwidth; + + if (bits > 0) { + int rate_error; + + rate_error = (int)((rc->vbr_bits_off_target * 100) / bits); + rate_error = clamp(rate_error, -100, 100); + if (rate_error > 0) { + rc_factor = AOMMAX(RC_FACTOR_MIN, (double)(100 - rate_error) / 100.0); + } else { + rc_factor = AOMMIN(RC_FACTOR_MAX, (double)(100 - rate_error) / 100.0); + } + } + + tmp_q = get_twopass_worst_quality( + cpi, group_av_err, (group_av_skip_pct + group_av_inactive_zone), + vbr_group_bits_per_frame, rc_factor); + rc->active_worst_quality = AOMMAX(tmp_q, rc->active_worst_quality >> 1); + } +#endif + + // Adjust KF group bits and error remaining. + if (is_final_pass) + twopass->kf_group_error_left -= (int64_t)gf_stats.gf_group_err; + + // Set up the structure of this Group-Of-Pictures (same as GF_GROUP) + av1_gop_setup_structure(cpi, frame_params); + + // Reset the file position. + reset_fpf_position(twopass, start_pos); + + // Calculate a section intra ratio used in setting max loop filter. + if (frame_params->frame_type != KEY_FRAME) { + twopass->section_intra_rating = calculate_section_intra_ratio( + start_pos, twopass->stats_buf_ctx->stats_in_end, + rc->baseline_gf_interval); + } + + // Reset rolling actual and target bits counters for ARF groups. + twopass->rolling_arf_group_target_bits = 1; + twopass->rolling_arf_group_actual_bits = 1; + + av1_gop_bit_allocation(cpi, rc, gf_group, + frame_params->frame_type == KEY_FRAME, use_alt_ref, + gf_group_bits); +} + +// #define FIXED_ARF_BITS +#ifdef FIXED_ARF_BITS +#define ARF_BITS_FRACTION 0.75 +#endif +void av1_gop_bit_allocation(const AV1_COMP *cpi, RATE_CONTROL *const rc, + GF_GROUP *gf_group, int is_key_frame, int use_arf, + int64_t gf_group_bits) { + // Calculate the extra bits to be used for boosted frame(s) +#ifdef FIXED_ARF_BITS + int gf_arf_bits = (int)(ARF_BITS_FRACTION * gf_group_bits); +#else + int gf_arf_bits = calculate_boost_bits(rc->baseline_gf_interval, + rc->gfu_boost, gf_group_bits); +#endif + + gf_arf_bits = adjust_boost_bits_for_target_level(cpi, rc, gf_arf_bits, + gf_group_bits, 1); + + // Allocate bits to each of the frames in the GF group. + allocate_gf_group_bits(gf_group, rc, gf_group_bits, gf_arf_bits, is_key_frame, + use_arf); +} + +// Minimum % intra coding observed in first pass (1.0 = 100%) +#define MIN_INTRA_LEVEL 0.25 +// Minimum ratio between the % of intra coding and inter coding in the first +// pass after discounting neutral blocks (discounting neutral blocks in this +// way helps catch scene cuts in clips with very flat areas or letter box +// format clips with image padding. +#define INTRA_VS_INTER_THRESH 2.0 +// Hard threshold where the first pass chooses intra for almost all blocks. +// In such a case even if the frame is not a scene cut coding a key frame +// may be a good option. +#define VERY_LOW_INTER_THRESH 0.05 +// Maximum threshold for the relative ratio of intra error score vs best +// inter error score. +#define KF_II_ERR_THRESHOLD 2.5 +// In real scene cuts there is almost always a sharp change in the intra +// or inter error score. +#define ERR_CHANGE_THRESHOLD 0.4 +// For real scene cuts we expect an improvment in the intra inter error +// ratio in the next frame. +#define II_IMPROVEMENT_THRESHOLD 3.5 +#define KF_II_MAX 128.0 + +// Threshold for use of the lagging second reference frame. High second ref +// usage may point to a transient event like a flash or occlusion rather than +// a real scene cut. +// We adapt the threshold based on number of frames in this key-frame group so +// far. +static double get_second_ref_usage_thresh(int frame_count_so_far) { + const int adapt_upto = 32; + const double min_second_ref_usage_thresh = 0.085; + const double second_ref_usage_thresh_max_delta = 0.035; + if (frame_count_so_far >= adapt_upto) { + return min_second_ref_usage_thresh + second_ref_usage_thresh_max_delta; + } + return min_second_ref_usage_thresh + + ((double)frame_count_so_far / (adapt_upto - 1)) * + second_ref_usage_thresh_max_delta; +} + +static int test_candidate_kf(TWO_PASS *twopass, + const FIRSTPASS_STATS *last_frame, + const FIRSTPASS_STATS *this_frame, + const FIRSTPASS_STATS *next_frame, + int frame_count_so_far, enum aom_rc_mode rc_mode) { + int is_viable_kf = 0; + double pcnt_intra = 1.0 - this_frame->pcnt_inter; + double modified_pcnt_inter = + this_frame->pcnt_inter - this_frame->pcnt_neutral; + const double second_ref_usage_thresh = + get_second_ref_usage_thresh(frame_count_so_far); + + // Does the frame satisfy the primary criteria of a key frame? + // See above for an explanation of the test criteria. + // If so, then examine how well it predicts subsequent frames. + if (IMPLIES(rc_mode == AOM_Q, frame_count_so_far >= 3) && + (this_frame->pcnt_second_ref < second_ref_usage_thresh) && + (next_frame->pcnt_second_ref < second_ref_usage_thresh) && + ((this_frame->pcnt_inter < VERY_LOW_INTER_THRESH) || + ((pcnt_intra > MIN_INTRA_LEVEL) && + (pcnt_intra > (INTRA_VS_INTER_THRESH * modified_pcnt_inter)) && + ((this_frame->intra_error / + DOUBLE_DIVIDE_CHECK(this_frame->coded_error)) < + KF_II_ERR_THRESHOLD) && + ((fabs(last_frame->coded_error - this_frame->coded_error) / + DOUBLE_DIVIDE_CHECK(this_frame->coded_error) > + ERR_CHANGE_THRESHOLD) || + (fabs(last_frame->intra_error - this_frame->intra_error) / + DOUBLE_DIVIDE_CHECK(this_frame->intra_error) > + ERR_CHANGE_THRESHOLD) || + ((next_frame->intra_error / + DOUBLE_DIVIDE_CHECK(next_frame->coded_error)) > + II_IMPROVEMENT_THRESHOLD))))) { + int i; + const FIRSTPASS_STATS *start_pos = twopass->stats_in; + FIRSTPASS_STATS local_next_frame = *next_frame; + double boost_score = 0.0; + double old_boost_score = 0.0; + double decay_accumulator = 1.0; + + // Examine how well the key frame predicts subsequent frames. + for (i = 0; i < SCENE_CUT_KEY_TEST_INTERVAL; ++i) { + double next_iiratio = (BOOST_FACTOR * local_next_frame.intra_error / + DOUBLE_DIVIDE_CHECK(local_next_frame.coded_error)); + + if (next_iiratio > KF_II_MAX) next_iiratio = KF_II_MAX; + + // Cumulative effect of decay in prediction quality. + if (local_next_frame.pcnt_inter > 0.85) + decay_accumulator *= local_next_frame.pcnt_inter; + else + decay_accumulator *= (0.85 + local_next_frame.pcnt_inter) / 2.0; + + // Keep a running total. + boost_score += (decay_accumulator * next_iiratio); + + // Test various breakout clauses. + if ((local_next_frame.pcnt_inter < 0.05) || (next_iiratio < 1.5) || + (((local_next_frame.pcnt_inter - local_next_frame.pcnt_neutral) < + 0.20) && + (next_iiratio < 3.0)) || + ((boost_score - old_boost_score) < 3.0) || + (local_next_frame.intra_error < 200)) { + break; + } + + old_boost_score = boost_score; + + // Get the next frame details + if (EOF == input_stats(twopass, &local_next_frame)) break; + } + + // If there is tolerable prediction for at least the next 3 frames then + // break out else discard this potential key frame and move on + if (boost_score > 30.0 && (i > 3)) { + is_viable_kf = 1; + } else { + // Reset the file position + reset_fpf_position(twopass, start_pos); + + is_viable_kf = 0; + } + } + + return is_viable_kf; +} + +#define FRAMES_TO_CHECK_DECAY 8 +#define KF_MIN_FRAME_BOOST 80.0 +#define KF_MAX_FRAME_BOOST 128.0 +#define MIN_KF_BOOST 600 // Minimum boost for non-static KF interval +#define MAX_KF_BOOST 3200 +#define MIN_STATIC_KF_BOOST 5400 // Minimum boost for static KF interval + +static int detect_app_forced_key(AV1_COMP *cpi) { + if (cpi->oxcf.fwd_kf_enabled) cpi->rc.next_is_fwd_key = 1; + int num_frames_to_app_forced_key = is_forced_keyframe_pending( + cpi->lookahead, cpi->lookahead->max_sz, cpi->compressor_stage); + if (num_frames_to_app_forced_key != -1) cpi->rc.next_is_fwd_key = 0; + return num_frames_to_app_forced_key; +} + +static int get_projected_kf_boost(AV1_COMP *cpi) { + /* + * If num_stats_used_for_kf_boost >= frames_to_key, then + * all stats needed for prior boost calculation are available. + * Hence projecting the prior boost is not needed in this cases. + */ + if (cpi->rc.num_stats_used_for_kf_boost >= cpi->rc.frames_to_key) + return cpi->rc.kf_boost; + + // Get the current tpl factor (number of frames = frames_to_key). + double tpl_factor = av1_get_kf_boost_projection_factor(cpi->rc.frames_to_key); + // Get the tpl factor when number of frames = num_stats_used_for_kf_boost. + double tpl_factor_num_stats = + av1_get_kf_boost_projection_factor(cpi->rc.num_stats_used_for_kf_boost); + int projected_kf_boost = + (int)rint((tpl_factor * cpi->rc.kf_boost) / tpl_factor_num_stats); + return projected_kf_boost; +} + +static int define_kf_interval(AV1_COMP *cpi, FIRSTPASS_STATS *this_frame, + double *kf_group_err, + int num_frames_to_detect_scenecut) { + TWO_PASS *const twopass = &cpi->twopass; + RATE_CONTROL *const rc = &cpi->rc; + const AV1EncoderConfig *const oxcf = &cpi->oxcf; + double recent_loop_decay[FRAMES_TO_CHECK_DECAY]; + FIRSTPASS_STATS last_frame; + double decay_accumulator = 1.0; + int i = 0, j; + int frames_to_key = 1; + int frames_since_key = rc->frames_since_key + 1; + FRAME_INFO *const frame_info = &cpi->frame_info; + int num_stats_used_for_kf_boost = 1; + int scenecut_detected = 0; + + int num_frames_to_next_key = detect_app_forced_key(cpi); + + if (num_frames_to_detect_scenecut == 0) { + if (num_frames_to_next_key != -1) + return num_frames_to_next_key; + else + return rc->frames_to_key; + } + + if (num_frames_to_next_key != -1) + num_frames_to_detect_scenecut = + AOMMIN(num_frames_to_detect_scenecut, num_frames_to_next_key); + + // Initialize the decay rates for the recent frames to check + for (j = 0; j < FRAMES_TO_CHECK_DECAY; ++j) recent_loop_decay[j] = 1.0; + + i = 0; + while (twopass->stats_in < twopass->stats_buf_ctx->stats_in_end && + frames_to_key < num_frames_to_detect_scenecut) { + // Accumulate total number of stats available till next key frame + num_stats_used_for_kf_boost++; + + // Accumulate kf group error. + if (kf_group_err != NULL) + *kf_group_err += + calculate_modified_err(frame_info, twopass, oxcf, this_frame); + + // Load the next frame's stats. + last_frame = *this_frame; + input_stats(twopass, this_frame); + + // Provided that we are not at the end of the file... + if (cpi->rc.enable_scenecut_detection && cpi->oxcf.auto_key && + twopass->stats_in < twopass->stats_buf_ctx->stats_in_end) { + double loop_decay_rate; + + // Check for a scene cut. + if (test_candidate_kf(twopass, &last_frame, this_frame, twopass->stats_in, + frames_since_key, oxcf->rc_mode)) { + scenecut_detected = 1; + break; + } + + // How fast is the prediction quality decaying? + loop_decay_rate = + get_prediction_decay_rate(frame_info, twopass->stats_in); + + // We want to know something about the recent past... rather than + // as used elsewhere where we are concerned with decay in prediction + // quality since the last GF or KF. + recent_loop_decay[i % FRAMES_TO_CHECK_DECAY] = loop_decay_rate; + decay_accumulator = 1.0; + for (j = 0; j < FRAMES_TO_CHECK_DECAY; ++j) + decay_accumulator *= recent_loop_decay[j]; + + // Special check for transition or high motion followed by a + // static scene. + if (detect_transition_to_still(twopass, rc->min_gf_interval, i, + cpi->oxcf.key_freq - i, loop_decay_rate, + decay_accumulator)) { + scenecut_detected = 1; + break; + } + + // Step on to the next frame. + ++frames_to_key; + ++frames_since_key; + + // If we don't have a real key frame within the next two + // key_freq intervals then break out of the loop. + if (frames_to_key >= 2 * cpi->oxcf.key_freq) break; + } else { + ++frames_to_key; + ++frames_since_key; + } + ++i; + } + + if (kf_group_err != NULL) + rc->num_stats_used_for_kf_boost = num_stats_used_for_kf_boost; + + if (cpi->lap_enabled && !scenecut_detected) + frames_to_key = num_frames_to_next_key; + + return frames_to_key; +} + +static void find_next_key_frame(AV1_COMP *cpi, FIRSTPASS_STATS *this_frame) { + RATE_CONTROL *const rc = &cpi->rc; + TWO_PASS *const twopass = &cpi->twopass; + GF_GROUP *const gf_group = &cpi->gf_group; + FRAME_INFO *const frame_info = &cpi->frame_info; + AV1_COMMON *const cm = &cpi->common; + CurrentFrame *const current_frame = &cm->current_frame; + const AV1EncoderConfig *const oxcf = &cpi->oxcf; + const FIRSTPASS_STATS first_frame = *this_frame; + FIRSTPASS_STATS next_frame; + av1_zero(next_frame); + + rc->frames_since_key = 0; + + // Reset the GF group data structures. + av1_zero(*gf_group); + + // Clear the alt ref active flag and last group multi arf flags as they + // can never be set for a key frame. + rc->source_alt_ref_active = 0; + + // KF is always a GF so clear frames till next gf counter. + rc->frames_till_gf_update_due = 0; + + rc->frames_to_key = 1; + + if (has_no_stats_stage(cpi)) { + int num_frames_to_app_forced_key = detect_app_forced_key(cpi); + rc->this_key_frame_forced = + current_frame->frame_number != 0 && rc->frames_to_key == 0; + if (num_frames_to_app_forced_key != -1) + rc->frames_to_key = num_frames_to_app_forced_key; + else + rc->frames_to_key = AOMMAX(1, cpi->oxcf.key_freq); + correct_frames_to_key(cpi); + rc->kf_boost = DEFAULT_KF_BOOST; + rc->source_alt_ref_active = 0; + gf_group->update_type[0] = KF_UPDATE; + return; + } + int i; + const FIRSTPASS_STATS *const start_position = twopass->stats_in; + int kf_bits = 0; + double zero_motion_accumulator = 1.0; + double boost_score = 0.0; + double kf_raw_err = 0.0; + double kf_mod_err = 0.0; + double kf_group_err = 0.0; + double sr_accumulator = 0.0; + int frames_to_key; + // Is this a forced key frame by interval. + rc->this_key_frame_forced = rc->next_key_frame_forced; + + twopass->kf_group_bits = 0; // Total bits available to kf group + twopass->kf_group_error_left = 0; // Group modified error score. + + kf_raw_err = this_frame->intra_error; + kf_mod_err = calculate_modified_err(frame_info, twopass, oxcf, this_frame); + + frames_to_key = + define_kf_interval(cpi, this_frame, &kf_group_err, oxcf->key_freq); + + if (frames_to_key != -1) + rc->frames_to_key = AOMMIN(oxcf->key_freq, frames_to_key); + else + rc->frames_to_key = oxcf->key_freq; + + if (cpi->lap_enabled) correct_frames_to_key(cpi); + + // If there is a max kf interval set by the user we must obey it. + // We already breakout of the loop above at 2x max. + // This code centers the extra kf if the actual natural interval + // is between 1x and 2x. + if (cpi->oxcf.auto_key && rc->frames_to_key > cpi->oxcf.key_freq) { + FIRSTPASS_STATS tmp_frame = first_frame; + + rc->frames_to_key /= 2; + + // Reset to the start of the group. + reset_fpf_position(twopass, start_position); + + kf_group_err = 0.0; + + // Rescan to get the correct error data for the forced kf group. + for (i = 0; i < rc->frames_to_key; ++i) { + kf_group_err += + calculate_modified_err(frame_info, twopass, oxcf, &tmp_frame); + if (EOF == input_stats(twopass, &tmp_frame)) break; + } + rc->next_key_frame_forced = 1; + } else if ((twopass->stats_in == twopass->stats_buf_ctx->stats_in_end && + is_stat_consumption_stage_twopass(cpi)) || + rc->frames_to_key >= cpi->oxcf.key_freq) { + rc->next_key_frame_forced = 1; + } else { + rc->next_key_frame_forced = 0; + } + + // Special case for the last key frame of the file. + if (twopass->stats_in >= twopass->stats_buf_ctx->stats_in_end) { + // Accumulate kf group error. + kf_group_err += + calculate_modified_err(frame_info, twopass, oxcf, this_frame); + } + + // Calculate the number of bits that should be assigned to the kf group. + if (twopass->bits_left > 0 && twopass->modified_error_left > 0.0) { + // Maximum number of bits for a single normal frame (not key frame). + const int max_bits = frame_max_bits(rc, &cpi->oxcf); + + // Maximum number of bits allocated to the key frame group. + int64_t max_grp_bits; + + // Default allocation based on bits left and relative + // complexity of the section. + twopass->kf_group_bits = (int64_t)( + twopass->bits_left * (kf_group_err / twopass->modified_error_left)); + + // Clip based on maximum per frame rate defined by the user. + max_grp_bits = (int64_t)max_bits * (int64_t)rc->frames_to_key; + if (twopass->kf_group_bits > max_grp_bits) + twopass->kf_group_bits = max_grp_bits; + } else { + twopass->kf_group_bits = 0; + } + twopass->kf_group_bits = AOMMAX(0, twopass->kf_group_bits); + + // Reset the first pass file position. + reset_fpf_position(twopass, start_position); + + // Scan through the kf group collating various stats used to determine + // how many bits to spend on it. + boost_score = 0.0; + const double kf_max_boost = + cpi->oxcf.rc_mode == AOM_Q + ? AOMMIN(AOMMAX(rc->frames_to_key * 2.0, KF_MIN_FRAME_BOOST), + KF_MAX_FRAME_BOOST) + : KF_MAX_FRAME_BOOST; + for (i = 0; i < (rc->frames_to_key - 1); ++i) { + if (EOF == input_stats(twopass, &next_frame)) break; + + // Monitor for static sections. + // For the first frame in kf group, the second ref indicator is invalid. + if (i > 0) { + zero_motion_accumulator = + AOMMIN(zero_motion_accumulator, + get_zero_motion_factor(frame_info, &next_frame)); + } else { + zero_motion_accumulator = next_frame.pcnt_inter - next_frame.pcnt_motion; + } + + // Not all frames in the group are necessarily used in calculating boost. + if ((sr_accumulator < (kf_raw_err * 1.50)) && + (i <= rc->max_gf_interval * 2)) { + double frame_boost; + double zm_factor; + + // Factor 0.75-1.25 based on how much of frame is static. + zm_factor = (0.75 + (zero_motion_accumulator / 2.0)); + + if (i < 2) sr_accumulator = 0.0; + frame_boost = calc_kf_frame_boost(rc, frame_info, &next_frame, + &sr_accumulator, kf_max_boost); + boost_score += frame_boost * zm_factor; + } + } + + reset_fpf_position(twopass, start_position); + + // Store the zero motion percentage + twopass->kf_zeromotion_pct = (int)(zero_motion_accumulator * 100.0); + + // Calculate a section intra ratio used in setting max loop filter. + twopass->section_intra_rating = calculate_section_intra_ratio( + start_position, twopass->stats_buf_ctx->stats_in_end, rc->frames_to_key); + + rc->kf_boost = (int)boost_score; + + if (cpi->lap_enabled) { + rc->kf_boost = get_projected_kf_boost(cpi); + } + + // Special case for static / slide show content but don't apply + // if the kf group is very short. + if ((zero_motion_accumulator > STATIC_KF_GROUP_FLOAT_THRESH) && + (rc->frames_to_key > 8)) { + rc->kf_boost = AOMMAX(rc->kf_boost, MIN_STATIC_KF_BOOST); + } else { + // Apply various clamps for min and max boost + rc->kf_boost = AOMMAX(rc->kf_boost, (rc->frames_to_key * 3)); + rc->kf_boost = AOMMAX(rc->kf_boost, MIN_KF_BOOST); +#ifdef STRICT_RC + rc->kf_boost = AOMMIN(rc->kf_boost, MAX_KF_BOOST); +#endif + } + + // Work out how many bits to allocate for the key frame itself. + kf_bits = calculate_boost_bits((rc->frames_to_key - 1), rc->kf_boost, + twopass->kf_group_bits); + // printf("kf boost = %d kf_bits = %d kf_zeromotion_pct = %d\n", rc->kf_boost, + // kf_bits, twopass->kf_zeromotion_pct); + kf_bits = adjust_boost_bits_for_target_level(cpi, rc, kf_bits, + twopass->kf_group_bits, 0); + + twopass->kf_group_bits -= kf_bits; + + // Save the bits to spend on the key frame. + gf_group->bit_allocation[0] = kf_bits; + gf_group->update_type[0] = KF_UPDATE; + + // Note the total error score of the kf group minus the key frame itself. + twopass->kf_group_error_left = (int)(kf_group_err - kf_mod_err); + + // Adjust the count of total modified error left. + // The count of bits left is adjusted elsewhere based on real coded frame + // sizes. + twopass->modified_error_left -= kf_group_err; +} + +static int is_skippable_frame(const AV1_COMP *cpi) { + if (has_no_stats_stage(cpi)) return 0; + // If the current frame does not have non-zero motion vector detected in the + // first pass, and so do its previous and forward frames, then this frame + // can be skipped for partition check, and the partition size is assigned + // according to the variance + const TWO_PASS *const twopass = &cpi->twopass; + + return (!frame_is_intra_only(&cpi->common) && + twopass->stats_in - 2 > twopass->stats_buf_ctx->stats_in_start && + twopass->stats_in < twopass->stats_buf_ctx->stats_in_end && + (twopass->stats_in - 1)->pcnt_inter - + (twopass->stats_in - 1)->pcnt_motion == + 1 && + (twopass->stats_in - 2)->pcnt_inter - + (twopass->stats_in - 2)->pcnt_motion == + 1 && + twopass->stats_in->pcnt_inter - twopass->stats_in->pcnt_motion == 1); +} + +#define ARF_STATS_OUTPUT 0 +#if ARF_STATS_OUTPUT +unsigned int arf_count = 0; +#endif +#define DEFAULT_GRP_WEIGHT 1.0 + +static void process_first_pass_stats(AV1_COMP *cpi, + FIRSTPASS_STATS *this_frame) { + AV1_COMMON *const cm = &cpi->common; + CurrentFrame *const current_frame = &cm->current_frame; + RATE_CONTROL *const rc = &cpi->rc; + TWO_PASS *const twopass = &cpi->twopass; + + if (cpi->oxcf.rc_mode != AOM_Q && current_frame->frame_number == 0 && + cpi->twopass.stats_buf_ctx->total_stats && + cpi->twopass.stats_buf_ctx->total_left_stats) { + if (cpi->lap_enabled) { + /* + * Accumulate total_stats using available limited number of stats, + * and assign it to total_left_stats. + */ + *cpi->twopass.stats_buf_ctx->total_left_stats = + *cpi->twopass.stats_buf_ctx->total_stats; + } + const int frames_left = (int)(twopass->stats_buf_ctx->total_stats->count - + current_frame->frame_number); + + // Special case code for first frame. + const int section_target_bandwidth = + (int)(twopass->bits_left / frames_left); + const double section_length = + twopass->stats_buf_ctx->total_left_stats->count; + const double section_error = + twopass->stats_buf_ctx->total_left_stats->coded_error / section_length; + const double section_intra_skip = + twopass->stats_buf_ctx->total_left_stats->intra_skip_pct / + section_length; + const double section_inactive_zone = + (twopass->stats_buf_ctx->total_left_stats->inactive_zone_rows * 2) / + ((double)cm->mi_params.mb_rows * section_length); + const int tmp_q = get_twopass_worst_quality( + cpi, section_error, section_intra_skip + section_inactive_zone, + section_target_bandwidth, DEFAULT_GRP_WEIGHT); + + rc->active_worst_quality = tmp_q; + rc->ni_av_qi = tmp_q; + rc->last_q[INTER_FRAME] = tmp_q; + rc->avg_q = av1_convert_qindex_to_q(tmp_q, cm->seq_params.bit_depth); + rc->avg_frame_qindex[INTER_FRAME] = tmp_q; + rc->last_q[KEY_FRAME] = (tmp_q + cpi->oxcf.best_allowed_q) / 2; + rc->avg_frame_qindex[KEY_FRAME] = rc->last_q[KEY_FRAME]; + } + + int err = 0; + if (cpi->lap_enabled) { + err = input_stats_lap(twopass, this_frame); + } else { + err = input_stats(twopass, this_frame); + } + if (err == EOF) return; + + { + const int num_mbs = (cpi->oxcf.resize_mode != RESIZE_NONE) + ? cpi->initial_mbs + : cm->mi_params.MBs; + // The multiplication by 256 reverses a scaling factor of (>> 8) + // applied when combining MB error values for the frame. + twopass->mb_av_energy = log((this_frame->intra_error / num_mbs) + 1.0); + twopass->frame_avg_haar_energy = + log((this_frame->frame_avg_wavelet_energy / num_mbs) + 1.0); + } + + // Update the total stats remaining structure. + if (twopass->stats_buf_ctx->total_left_stats) + subtract_stats(twopass->stats_buf_ctx->total_left_stats, this_frame); + + // Set the frame content type flag. + if (this_frame->intra_skip_pct >= FC_ANIMATION_THRESH) + twopass->fr_content_type = FC_GRAPHICS_ANIMATION; + else + twopass->fr_content_type = FC_NORMAL; +} + +static void setup_target_rate(AV1_COMP *cpi) { + RATE_CONTROL *const rc = &cpi->rc; + GF_GROUP *const gf_group = &cpi->gf_group; + + int target_rate = gf_group->bit_allocation[gf_group->index]; + + if (has_no_stats_stage(cpi)) { + av1_rc_set_frame_target(cpi, target_rate, cpi->common.width, + cpi->common.height); + } + + rc->base_frame_target = target_rate; +} + +void av1_get_second_pass_params(AV1_COMP *cpi, + EncodeFrameParams *const frame_params, + const EncodeFrameInput *const frame_input, + unsigned int frame_flags) { + RATE_CONTROL *const rc = &cpi->rc; + TWO_PASS *const twopass = &cpi->twopass; + GF_GROUP *const gf_group = &cpi->gf_group; + AV1_COMMON *cm = &cpi->common; + + if (frame_is_intra_only(cm)) { + FeatureFlags *const features = &cm->features; + av1_set_screen_content_options(cpi, features); + cpi->is_screen_content_type = features->allow_screen_content_tools; + } + + if (is_stat_consumption_stage(cpi) && !twopass->stats_in) return; + + if (rc->frames_till_gf_update_due > 0 && !(frame_flags & FRAMEFLAGS_KEY)) { + assert(gf_group->index < gf_group->size); + const int update_type = gf_group->update_type[gf_group->index]; + + setup_target_rate(cpi); + + // If this is an arf frame then we dont want to read the stats file or + // advance the input pointer as we already have what we need. + if (update_type == ARF_UPDATE || update_type == INTNL_ARF_UPDATE) { + if (cpi->no_show_kf) { + assert(update_type == ARF_UPDATE); + frame_params->frame_type = KEY_FRAME; + } else { + frame_params->frame_type = INTER_FRAME; + } + + // Do the firstpass stats indicate that this frame is skippable for the + // partition search? + if (cpi->sf.part_sf.allow_partition_search_skip && cpi->oxcf.pass == 2) { + cpi->partition_search_skippable_frame = is_skippable_frame(cpi); + } + + return; + } + } + + aom_clear_system_state(); + + if (cpi->oxcf.rc_mode == AOM_Q) rc->active_worst_quality = cpi->oxcf.cq_level; + FIRSTPASS_STATS this_frame; + av1_zero(this_frame); + // call above fn + if (is_stat_consumption_stage(cpi)) { + process_first_pass_stats(cpi, &this_frame); + } else { + rc->active_worst_quality = cpi->oxcf.cq_level; + } + + // Keyframe and section processing. + if (rc->frames_to_key == 0 || (frame_flags & FRAMEFLAGS_KEY)) { + FIRSTPASS_STATS this_frame_copy; + this_frame_copy = this_frame; + frame_params->frame_type = KEY_FRAME; + // Define next KF group and assign bits to it. + find_next_key_frame(cpi, &this_frame); + this_frame = this_frame_copy; + } else { + frame_params->frame_type = INTER_FRAME; + const int altref_enabled = is_altref_enabled(cpi); + const int sframe_dist = cpi->oxcf.sframe_dist; + const int sframe_mode = cpi->oxcf.sframe_mode; + const int sframe_enabled = cpi->oxcf.sframe_enabled; + const int update_type = gf_group->update_type[gf_group->index]; + CurrentFrame *const current_frame = &cpi->common.current_frame; + if (sframe_enabled) { + if (altref_enabled) { + if (sframe_mode == 1) { + // sframe_mode == 1: insert sframe if it matches altref frame. + if (current_frame->frame_number % sframe_dist == 0 && + current_frame->frame_number != 0 && update_type == ARF_UPDATE) { + frame_params->frame_type = S_FRAME; + } + } else { + // sframe_mode != 1: if sframe will be inserted at the next available + // altref frame + if (current_frame->frame_number % sframe_dist == 0 && + current_frame->frame_number != 0) { + rc->sframe_due = 1; + } + if (rc->sframe_due && update_type == ARF_UPDATE) { + frame_params->frame_type = S_FRAME; + rc->sframe_due = 0; + } + } + } else { + if (current_frame->frame_number % sframe_dist == 0 && + current_frame->frame_number != 0) { + frame_params->frame_type = S_FRAME; + } + } + } + } + + // Define a new GF/ARF group. (Should always enter here for key frames). + if (rc->frames_till_gf_update_due == 0) { + assert(cpi->common.current_frame.frame_number == 0 || + gf_group->index == gf_group->size); + const FIRSTPASS_STATS *const start_position = twopass->stats_in; + int num_frames_to_detect_scenecut, frames_to_key; + if (cpi->lap_enabled && cpi->rc.enable_scenecut_detection) + num_frames_to_detect_scenecut = MAX_GF_LENGTH_LAP + 1; + else + num_frames_to_detect_scenecut = 0; + frames_to_key = define_kf_interval(cpi, &this_frame, NULL, + num_frames_to_detect_scenecut); + reset_fpf_position(twopass, start_position); + if (frames_to_key != -1) + rc->frames_to_key = AOMMIN(rc->frames_to_key, frames_to_key); + + int max_gop_length = (cpi->oxcf.lag_in_frames >= 32 && + is_stat_consumption_stage_twopass(cpi)) + ? MAX_GF_INTERVAL + : MAX_GF_LENGTH_LAP; + if (rc->intervals_till_gf_calculate_due == 0) { + calculate_gf_length(cpi, max_gop_length, MAX_NUM_GF_INTERVALS); + } + + if (max_gop_length > 16) { + if (rc->gf_intervals[rc->cur_gf_index] - 1 > 16) { + // The calculate_gf_length function is previously used with + // max_gop_length = 32 with look-ahead gf intervals. + define_gf_group(cpi, &this_frame, frame_params, max_gop_length, 0); + if (!av1_tpl_setup_stats(cpi, 1, frame_params, frame_input)) { + // Tpl decides that a shorter gf interval is better. + // TODO(jingning): Remove redundant computations here. + max_gop_length = 16; + calculate_gf_length(cpi, max_gop_length, 1); + } + } else { + // Even based on 32 we still decide to use a short gf interval. + // Better to re-decide based on 16 then + max_gop_length = 16; + calculate_gf_length(cpi, max_gop_length, 1); + } + } + define_gf_group(cpi, &this_frame, frame_params, max_gop_length, 1); + rc->frames_till_gf_update_due = rc->baseline_gf_interval; + cpi->num_gf_group_show_frames = 0; + assert(gf_group->index == 0); + +#if ARF_STATS_OUTPUT + { + FILE *fpfile; + fpfile = fopen("arf.stt", "a"); + ++arf_count; + fprintf(fpfile, "%10d %10d %10d %10d %10d\n", + cpi->common.current_frame.frame_number, + rc->frames_till_gf_update_due, rc->kf_boost, arf_count, + rc->gfu_boost); + + fclose(fpfile); + } +#endif + } + assert(gf_group->index < gf_group->size); + + // Do the firstpass stats indicate that this frame is skippable for the + // partition search? + if (cpi->sf.part_sf.allow_partition_search_skip && cpi->oxcf.pass == 2) { + cpi->partition_search_skippable_frame = is_skippable_frame(cpi); + } + + setup_target_rate(cpi); +} + +void av1_init_second_pass(AV1_COMP *cpi) { + const AV1EncoderConfig *const oxcf = &cpi->oxcf; + TWO_PASS *const twopass = &cpi->twopass; + FRAME_INFO *const frame_info = &cpi->frame_info; + double frame_rate; + FIRSTPASS_STATS *stats; + + if (!twopass->stats_buf_ctx->stats_in_end) return; + + stats = twopass->stats_buf_ctx->total_stats; + + *stats = *twopass->stats_buf_ctx->stats_in_end; + *twopass->stats_buf_ctx->total_left_stats = *stats; + + frame_rate = 10000000.0 * stats->count / stats->duration; + // Each frame can have a different duration, as the frame rate in the source + // isn't guaranteed to be constant. The frame rate prior to the first frame + // encoded in the second pass is a guess. However, the sum duration is not. + // It is calculated based on the actual durations of all frames from the + // first pass. + av1_new_framerate(cpi, frame_rate); + twopass->bits_left = + (int64_t)(stats->duration * oxcf->target_bandwidth / 10000000.0); + + // This variable monitors how far behind the second ref update is lagging. + twopass->sr_update_lag = 1; + + // Scan the first pass file and calculate a modified total error based upon + // the bias/power function used to allocate bits. + { + const double avg_error = + stats->coded_error / DOUBLE_DIVIDE_CHECK(stats->count); + const FIRSTPASS_STATS *s = twopass->stats_in; + double modified_error_total = 0.0; + twopass->modified_error_min = + (avg_error * oxcf->two_pass_vbrmin_section) / 100; + twopass->modified_error_max = + (avg_error * oxcf->two_pass_vbrmax_section) / 100; + while (s < twopass->stats_buf_ctx->stats_in_end) { + modified_error_total += + calculate_modified_err(frame_info, twopass, oxcf, s); + ++s; + } + twopass->modified_error_left = modified_error_total; + } + + // Reset the vbr bits off target counters + cpi->rc.vbr_bits_off_target = 0; + cpi->rc.vbr_bits_off_target_fast = 0; + + cpi->rc.rate_error_estimate = 0; + + // Static sequence monitor variables. + twopass->kf_zeromotion_pct = 100; + twopass->last_kfgroup_zeromotion_pct = 100; + + // Initialize bits per macro_block estimate correction factor. + twopass->bpm_factor = 1.0; + // Initialize actual and target bits counters for ARF groups so that + // at the start we have a neutral bpm adjustment. + twopass->rolling_arf_group_target_bits = 1; + twopass->rolling_arf_group_actual_bits = 1; +} + +void av1_init_single_pass_lap(AV1_COMP *cpi) { + TWO_PASS *const twopass = &cpi->twopass; + + if (!twopass->stats_buf_ctx->stats_in_end) return; + + // This variable monitors how far behind the second ref update is lagging. + twopass->sr_update_lag = 1; + + twopass->bits_left = 0; + twopass->modified_error_min = 0.0; + twopass->modified_error_max = 0.0; + twopass->modified_error_left = 0.0; + + // Reset the vbr bits off target counters + cpi->rc.vbr_bits_off_target = 0; + cpi->rc.vbr_bits_off_target_fast = 0; + + cpi->rc.rate_error_estimate = 0; + + // Static sequence monitor variables. + twopass->kf_zeromotion_pct = 100; + twopass->last_kfgroup_zeromotion_pct = 100; + + // Initialize bits per macro_block estimate correction factor. + twopass->bpm_factor = 1.0; + // Initialize actual and target bits counters for ARF groups so that + // at the start we have a neutral bpm adjustment. + twopass->rolling_arf_group_target_bits = 1; + twopass->rolling_arf_group_actual_bits = 1; +} + +#define MINQ_ADJ_LIMIT 48 +#define MINQ_ADJ_LIMIT_CQ 20 +#define HIGH_UNDERSHOOT_RATIO 2 +void av1_twopass_postencode_update(AV1_COMP *cpi) { + TWO_PASS *const twopass = &cpi->twopass; + RATE_CONTROL *const rc = &cpi->rc; + const int bits_used = rc->base_frame_target; + + // VBR correction is done through rc->vbr_bits_off_target. Based on the + // sign of this value, a limited % adjustment is made to the target rate + // of subsequent frames, to try and push it back towards 0. This method + // is designed to prevent extreme behaviour at the end of a clip + // or group of frames. + rc->vbr_bits_off_target += rc->base_frame_target - rc->projected_frame_size; + twopass->bits_left = AOMMAX(twopass->bits_left - bits_used, 0); + + // Target vs actual bits for this arf group. + twopass->rolling_arf_group_target_bits += rc->this_frame_target; + twopass->rolling_arf_group_actual_bits += rc->projected_frame_size; + + // Calculate the pct rc error. + if (rc->total_actual_bits) { + rc->rate_error_estimate = + (int)((rc->vbr_bits_off_target * 100) / rc->total_actual_bits); + rc->rate_error_estimate = clamp(rc->rate_error_estimate, -100, 100); + } else { + rc->rate_error_estimate = 0; + } + + // Update the active best quality pyramid. + if (!rc->is_src_frame_alt_ref) { + const int pyramid_level = cpi->gf_group.layer_depth[cpi->gf_group.index]; + int i; + for (i = pyramid_level; i <= MAX_ARF_LAYERS; ++i) { + rc->active_best_quality[i] = cpi->common.quant_params.base_qindex; + // if (pyramid_level >= 2) { + // rc->active_best_quality[pyramid_level] = + // AOMMAX(rc->active_best_quality[pyramid_level], + // cpi->common.base_qindex); + // } + } + } + +#if 0 + { + AV1_COMMON *cm = &cpi->common; + FILE *fpfile; + fpfile = fopen("details.stt", "a"); + fprintf(fpfile, + "%10d %10d %10d %10" PRId64 " %10" PRId64 + " %10d %10d %10d %10.4lf %10.4lf %10.4lf %10.4lf\n", + cm->current_frame.frame_number, rc->base_frame_target, + rc->projected_frame_size, rc->total_actual_bits, + rc->vbr_bits_off_target, rc->rate_error_estimate, + twopass->rolling_arf_group_target_bits, + twopass->rolling_arf_group_actual_bits, + (double)twopass->rolling_arf_group_actual_bits / + (double)twopass->rolling_arf_group_target_bits, + twopass->bpm_factor, + av1_convert_qindex_to_q(quant_params->base_qindex, + cm->seq_params.bit_depth), + av1_convert_qindex_to_q(rc->active_worst_quality, + cm->seq_params.bit_depth)); + fclose(fpfile); + } +#endif + + if (cpi->common.current_frame.frame_type != KEY_FRAME) { + twopass->kf_group_bits -= bits_used; + twopass->last_kfgroup_zeromotion_pct = twopass->kf_zeromotion_pct; + } + twopass->kf_group_bits = AOMMAX(twopass->kf_group_bits, 0); + + // If the rate control is drifting consider adjustment to min or maxq. + if ((cpi->oxcf.rc_mode != AOM_Q) && !cpi->rc.is_src_frame_alt_ref) { + const int maxq_adj_limit = rc->worst_quality - rc->active_worst_quality; + const int minq_adj_limit = + (cpi->oxcf.rc_mode == AOM_CQ ? MINQ_ADJ_LIMIT_CQ : MINQ_ADJ_LIMIT); + + // Undershoot. + if (rc->rate_error_estimate > cpi->oxcf.under_shoot_pct) { + --twopass->extend_maxq; + if (rc->rolling_target_bits >= rc->rolling_actual_bits) + ++twopass->extend_minq; + // Overshoot. + } else if (rc->rate_error_estimate < -cpi->oxcf.over_shoot_pct) { + --twopass->extend_minq; + if (rc->rolling_target_bits < rc->rolling_actual_bits) + ++twopass->extend_maxq; + } else { + // Adjustment for extreme local overshoot. + if (rc->projected_frame_size > (2 * rc->base_frame_target) && + rc->projected_frame_size > (2 * rc->avg_frame_bandwidth)) + ++twopass->extend_maxq; + + // Unwind undershoot or overshoot adjustment. + if (rc->rolling_target_bits < rc->rolling_actual_bits) + --twopass->extend_minq; + else if (rc->rolling_target_bits > rc->rolling_actual_bits) + --twopass->extend_maxq; + } + + twopass->extend_minq = clamp(twopass->extend_minq, 0, minq_adj_limit); + twopass->extend_maxq = clamp(twopass->extend_maxq, 0, maxq_adj_limit); + + // If there is a big and undexpected undershoot then feed the extra + // bits back in quickly. One situation where this may happen is if a + // frame is unexpectedly almost perfectly predicted by the ARF or GF + // but not very well predcited by the previous frame. + if (!frame_is_kf_gf_arf(cpi) && !cpi->rc.is_src_frame_alt_ref) { + int fast_extra_thresh = rc->base_frame_target / HIGH_UNDERSHOOT_RATIO; + if (rc->projected_frame_size < fast_extra_thresh) { + rc->vbr_bits_off_target_fast += + fast_extra_thresh - rc->projected_frame_size; + rc->vbr_bits_off_target_fast = + AOMMIN(rc->vbr_bits_off_target_fast, (4 * rc->avg_frame_bandwidth)); + + // Fast adaptation of minQ if necessary to use up the extra bits. + if (rc->avg_frame_bandwidth) { + twopass->extend_minq_fast = + (int)(rc->vbr_bits_off_target_fast * 8 / rc->avg_frame_bandwidth); + } + twopass->extend_minq_fast = AOMMIN( + twopass->extend_minq_fast, minq_adj_limit - twopass->extend_minq); + } else if (rc->vbr_bits_off_target_fast) { + twopass->extend_minq_fast = AOMMIN( + twopass->extend_minq_fast, minq_adj_limit - twopass->extend_minq); + } else { + twopass->extend_minq_fast = 0; + } + } + } +} |