diff options
Diffstat (limited to 'media/libopus/silk/NLSF2A.c')
| -rw-r--r-- | media/libopus/silk/NLSF2A.c | 59 |
1 files changed, 11 insertions, 48 deletions
diff --git a/media/libopus/silk/NLSF2A.c b/media/libopus/silk/NLSF2A.c index b1c559ea68..d5b7730638 100644 --- a/media/libopus/silk/NLSF2A.c +++ b/media/libopus/silk/NLSF2A.c @@ -66,7 +66,8 @@ static OPUS_INLINE void silk_NLSF2A_find_poly( void silk_NLSF2A( opus_int16 *a_Q12, /* O monic whitening filter coefficients in Q12, [ d ] */ const opus_int16 *NLSF, /* I normalized line spectral frequencies in Q15, [ d ] */ - const opus_int d /* I filter order (should be even) */ + const opus_int d, /* I filter order (should be even) */ + int arch /* I Run-time architecture */ ) { /* This ordering was found to maximize quality. It improves numerical accuracy of @@ -83,15 +84,14 @@ void silk_NLSF2A( opus_int32 P[ SILK_MAX_ORDER_LPC / 2 + 1 ], Q[ SILK_MAX_ORDER_LPC / 2 + 1 ]; opus_int32 Ptmp, Qtmp, f_int, f_frac, cos_val, delta; opus_int32 a32_QA1[ SILK_MAX_ORDER_LPC ]; - opus_int32 maxabs, absval, idx=0, sc_Q16; silk_assert( LSF_COS_TAB_SZ_FIX == 128 ); - silk_assert( d==10||d==16 ); + celt_assert( d==10 || d==16 ); /* convert LSFs to 2*cos(LSF), using piecewise linear curve from table */ ordering = d == 16 ? ordering16 : ordering10; for( k = 0; k < d; k++ ) { - silk_assert(NLSF[k] >= 0 ); + silk_assert( NLSF[k] >= 0 ); /* f_int on a scale 0-127 (rounded down) */ f_int = silk_RSHIFT( NLSF[k], 15 - 7 ); @@ -126,52 +126,15 @@ void silk_NLSF2A( a32_QA1[ d-k-1 ] = Qtmp - Ptmp; /* QA+1 */ } - /* Limit the maximum absolute value of the prediction coefficients, so that they'll fit in int16 */ - for( i = 0; i < 10; i++ ) { - /* Find maximum absolute value and its index */ - maxabs = 0; - for( k = 0; k < d; k++ ) { - absval = silk_abs( a32_QA1[k] ); - if( absval > maxabs ) { - maxabs = absval; - idx = k; - } - } - maxabs = silk_RSHIFT_ROUND( maxabs, QA + 1 - 12 ); /* QA+1 -> Q12 */ - - if( maxabs > silk_int16_MAX ) { - /* Reduce magnitude of prediction coefficients */ - maxabs = silk_min( maxabs, 163838 ); /* ( silk_int32_MAX >> 14 ) + silk_int16_MAX = 163838 */ - sc_Q16 = SILK_FIX_CONST( 0.999, 16 ) - silk_DIV32( silk_LSHIFT( maxabs - silk_int16_MAX, 14 ), - silk_RSHIFT32( silk_MUL( maxabs, idx + 1), 2 ) ); - silk_bwexpander_32( a32_QA1, d, sc_Q16 ); - } else { - break; - } - } + /* Convert int32 coefficients to Q12 int16 coefs */ + silk_LPC_fit( a_Q12, a32_QA1, 12, QA + 1, d ); - if( i == 10 ) { - /* Reached the last iteration, clip the coefficients */ + for( i = 0; silk_LPC_inverse_pred_gain( a_Q12, d, arch ) == 0 && i < MAX_LPC_STABILIZE_ITERATIONS; i++ ) { + /* Prediction coefficients are (too close to) unstable; apply bandwidth expansion */ + /* on the unscaled coefficients, convert to Q12 and measure again */ + silk_bwexpander_32( a32_QA1, d, 65536 - silk_LSHIFT( 2, i ) ); for( k = 0; k < d; k++ ) { - a_Q12[ k ] = (opus_int16)silk_SAT16( silk_RSHIFT_ROUND( a32_QA1[ k ], QA + 1 - 12 ) ); /* QA+1 -> Q12 */ - a32_QA1[ k ] = silk_LSHIFT( (opus_int32)a_Q12[ k ], QA + 1 - 12 ); - } - } else { - for( k = 0; k < d; k++ ) { - a_Q12[ k ] = (opus_int16)silk_RSHIFT_ROUND( a32_QA1[ k ], QA + 1 - 12 ); /* QA+1 -> Q12 */ - } - } - - for( i = 0; i < MAX_LPC_STABILIZE_ITERATIONS; i++ ) { - if( silk_LPC_inverse_pred_gain( a_Q12, d ) < SILK_FIX_CONST( 1.0 / MAX_PREDICTION_POWER_GAIN, 30 ) ) { - /* Prediction coefficients are (too close to) unstable; apply bandwidth expansion */ - /* on the unscaled coefficients, convert to Q12 and measure again */ - silk_bwexpander_32( a32_QA1, d, 65536 - silk_LSHIFT( 2, i ) ); - for( k = 0; k < d; k++ ) { - a_Q12[ k ] = (opus_int16)silk_RSHIFT_ROUND( a32_QA1[ k ], QA + 1 - 12 ); /* QA+1 -> Q12 */ - } - } else { - break; + a_Q12[ k ] = (opus_int16)silk_RSHIFT_ROUND( a32_QA1[ k ], QA + 1 - 12 ); /* QA+1 -> Q12 */ } } } |