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path: root/src/opus-1.0.2/silk/PLC.c
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diff --git a/src/opus-1.0.2/silk/PLC.c b/src/opus-1.0.2/silk/PLC.c
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--- a/src/opus-1.0.2/silk/PLC.c
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-/***********************************************************************
-Copyright (c) 2006-2011, Skype Limited. All rights reserved.
-Redistribution and use in source and binary forms, with or without
-modification, are permitted provided that the following conditions
-are met:
-- Redistributions of source code must retain the above copyright notice,
-this list of conditions and the following disclaimer.
-- Redistributions in binary form must reproduce the above copyright
-notice, this list of conditions and the following disclaimer in the
-documentation and/or other materials provided with the distribution.
-- Neither the name of Internet Society, IETF or IETF Trust, nor the
-names of specific contributors, may be used to endorse or promote
-products derived from this software without specific prior written
-permission.
-THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS “AS IS”
-AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
-IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
-ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
-LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
-CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
-SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
-INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
-CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
-ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
-POSSIBILITY OF SUCH DAMAGE.
-***********************************************************************/
-
-#ifdef HAVE_CONFIG_H
-#include "config.h"
-#endif
-
-#include "main.h"
-#include "stack_alloc.h"
-#include "PLC.h"
-
-#define NB_ATT 2
-static const opus_int16 HARM_ATT_Q15[NB_ATT] = { 32440, 31130 }; /* 0.99, 0.95 */
-static const opus_int16 PLC_RAND_ATTENUATE_V_Q15[NB_ATT] = { 31130, 26214 }; /* 0.95, 0.8 */
-static const opus_int16 PLC_RAND_ATTENUATE_UV_Q15[NB_ATT] = { 32440, 29491 }; /* 0.99, 0.9 */
-
-static inline void silk_PLC_update(
- silk_decoder_state *psDec, /* I/O Decoder state */
- silk_decoder_control *psDecCtrl /* I/O Decoder control */
-);
-
-static inline void silk_PLC_conceal(
- silk_decoder_state *psDec, /* I/O Decoder state */
- silk_decoder_control *psDecCtrl, /* I/O Decoder control */
- opus_int16 frame[] /* O LPC residual signal */
-);
-
-
-void silk_PLC_Reset(
- silk_decoder_state *psDec /* I/O Decoder state */
-)
-{
- psDec->sPLC.pitchL_Q8 = silk_LSHIFT( psDec->frame_length, 8 - 1 );
- psDec->sPLC.prevGain_Q16[ 0 ] = SILK_FIX_CONST( 1, 16 );
- psDec->sPLC.prevGain_Q16[ 1 ] = SILK_FIX_CONST( 1, 16 );
- psDec->sPLC.subfr_length = 20;
- psDec->sPLC.nb_subfr = 2;
-}
-
-void silk_PLC(
- silk_decoder_state *psDec, /* I/O Decoder state */
- silk_decoder_control *psDecCtrl, /* I/O Decoder control */
- opus_int16 frame[], /* I/O signal */
- opus_int lost /* I Loss flag */
-)
-{
- /* PLC control function */
- if( psDec->fs_kHz != psDec->sPLC.fs_kHz ) {
- silk_PLC_Reset( psDec );
- psDec->sPLC.fs_kHz = psDec->fs_kHz;
- }
-
- if( lost ) {
- /****************************/
- /* Generate Signal */
- /****************************/
- silk_PLC_conceal( psDec, psDecCtrl, frame );
-
- psDec->lossCnt++;
- } else {
- /****************************/
- /* Update state */
- /****************************/
- silk_PLC_update( psDec, psDecCtrl );
- }
-}
-
-/**************************************************/
-/* Update state of PLC */
-/**************************************************/
-static inline void silk_PLC_update(
- silk_decoder_state *psDec, /* I/O Decoder state */
- silk_decoder_control *psDecCtrl /* I/O Decoder control */
-)
-{
- opus_int32 LTP_Gain_Q14, temp_LTP_Gain_Q14;
- opus_int i, j;
- silk_PLC_struct *psPLC;
-
- psPLC = &psDec->sPLC;
-
- /* Update parameters used in case of packet loss */
- psDec->prevSignalType = psDec->indices.signalType;
- LTP_Gain_Q14 = 0;
- if( psDec->indices.signalType == TYPE_VOICED ) {
- /* Find the parameters for the last subframe which contains a pitch pulse */
- for( j = 0; j * psDec->subfr_length < psDecCtrl->pitchL[ psDec->nb_subfr - 1 ]; j++ ) {
- if( j == psDec->nb_subfr ) {
- break;
- }
- temp_LTP_Gain_Q14 = 0;
- for( i = 0; i < LTP_ORDER; i++ ) {
- temp_LTP_Gain_Q14 += psDecCtrl->LTPCoef_Q14[ ( psDec->nb_subfr - 1 - j ) * LTP_ORDER + i ];
- }
- if( temp_LTP_Gain_Q14 > LTP_Gain_Q14 ) {
- LTP_Gain_Q14 = temp_LTP_Gain_Q14;
- silk_memcpy( psPLC->LTPCoef_Q14,
- &psDecCtrl->LTPCoef_Q14[ silk_SMULBB( psDec->nb_subfr - 1 - j, LTP_ORDER ) ],
- LTP_ORDER * sizeof( opus_int16 ) );
-
- psPLC->pitchL_Q8 = silk_LSHIFT( psDecCtrl->pitchL[ psDec->nb_subfr - 1 - j ], 8 );
- }
- }
-
- silk_memset( psPLC->LTPCoef_Q14, 0, LTP_ORDER * sizeof( opus_int16 ) );
- psPLC->LTPCoef_Q14[ LTP_ORDER / 2 ] = LTP_Gain_Q14;
-
- /* Limit LT coefs */
- if( LTP_Gain_Q14 < V_PITCH_GAIN_START_MIN_Q14 ) {
- opus_int scale_Q10;
- opus_int32 tmp;
-
- tmp = silk_LSHIFT( V_PITCH_GAIN_START_MIN_Q14, 10 );
- scale_Q10 = silk_DIV32( tmp, silk_max( LTP_Gain_Q14, 1 ) );
- for( i = 0; i < LTP_ORDER; i++ ) {
- psPLC->LTPCoef_Q14[ i ] = silk_RSHIFT( silk_SMULBB( psPLC->LTPCoef_Q14[ i ], scale_Q10 ), 10 );
- }
- } else if( LTP_Gain_Q14 > V_PITCH_GAIN_START_MAX_Q14 ) {
- opus_int scale_Q14;
- opus_int32 tmp;
-
- tmp = silk_LSHIFT( V_PITCH_GAIN_START_MAX_Q14, 14 );
- scale_Q14 = silk_DIV32( tmp, silk_max( LTP_Gain_Q14, 1 ) );
- for( i = 0; i < LTP_ORDER; i++ ) {
- psPLC->LTPCoef_Q14[ i ] = silk_RSHIFT( silk_SMULBB( psPLC->LTPCoef_Q14[ i ], scale_Q14 ), 14 );
- }
- }
- } else {
- psPLC->pitchL_Q8 = silk_LSHIFT( silk_SMULBB( psDec->fs_kHz, 18 ), 8 );
- silk_memset( psPLC->LTPCoef_Q14, 0, LTP_ORDER * sizeof( opus_int16 ));
- }
-
- /* Save LPC coeficients */
- silk_memcpy( psPLC->prevLPC_Q12, psDecCtrl->PredCoef_Q12[ 1 ], psDec->LPC_order * sizeof( opus_int16 ) );
- psPLC->prevLTP_scale_Q14 = psDecCtrl->LTP_scale_Q14;
-
- /* Save last two gains */
- silk_memcpy( psPLC->prevGain_Q16, &psDecCtrl->Gains_Q16[ psDec->nb_subfr - 2 ], 2 * sizeof( opus_int32 ) );
-
- psPLC->subfr_length = psDec->subfr_length;
- psPLC->nb_subfr = psDec->nb_subfr;
-}
-
-static inline void silk_PLC_conceal(
- silk_decoder_state *psDec, /* I/O Decoder state */
- silk_decoder_control *psDecCtrl, /* I/O Decoder control */
- opus_int16 frame[] /* O LPC residual signal */
-)
-{
- opus_int i, j, k;
- opus_int lag, idx, sLTP_buf_idx, shift1, shift2;
- opus_int32 rand_seed, harm_Gain_Q15, rand_Gain_Q15, inv_gain_Q30;
- opus_int32 energy1, energy2, *rand_ptr, *pred_lag_ptr;
- opus_int32 LPC_pred_Q10, LTP_pred_Q12;
- opus_int16 rand_scale_Q14;
- opus_int16 *B_Q14, *exc_buf_ptr;
- opus_int32 *sLPC_Q14_ptr;
- VARDECL( opus_int16, exc_buf );
- opus_int16 A_Q12[ MAX_LPC_ORDER ];
- VARDECL( opus_int16, sLTP );
- VARDECL( opus_int32, sLTP_Q14 );
- silk_PLC_struct *psPLC = &psDec->sPLC;
- opus_int32 prevGain_Q10[2];
- SAVE_STACK;
-
- ALLOC( exc_buf, 2*psPLC->subfr_length, opus_int16 );
- ALLOC( sLTP, psDec->ltp_mem_length, opus_int16 );
- ALLOC( sLTP_Q14, psDec->ltp_mem_length + psDec->frame_length, opus_int32 );
-
- prevGain_Q10[0] = silk_RSHIFT( psPLC->prevGain_Q16[ 0 ], 6);
- prevGain_Q10[1] = silk_RSHIFT( psPLC->prevGain_Q16[ 1 ], 6);
-
- if( psDec->first_frame_after_reset ) {
- silk_memset( psPLC->prevLPC_Q12, 0, sizeof( psPLC->prevLPC_Q12 ) );
- }
-
- /* Find random noise component */
- /* Scale previous excitation signal */
- exc_buf_ptr = exc_buf;
- for( k = 0; k < 2; k++ ) {
- for( i = 0; i < psPLC->subfr_length; i++ ) {
- exc_buf_ptr[ i ] = (opus_int16)silk_SAT16( silk_RSHIFT(
- silk_SMULWW( psDec->exc_Q14[ i + ( k + psPLC->nb_subfr - 2 ) * psPLC->subfr_length ], prevGain_Q10[ k ] ), 8 ) );
- }
- exc_buf_ptr += psPLC->subfr_length;
- }
- /* Find the subframe with lowest energy of the last two and use that as random noise generator */
- silk_sum_sqr_shift( &energy1, &shift1, exc_buf, psPLC->subfr_length );
- silk_sum_sqr_shift( &energy2, &shift2, &exc_buf[ psPLC->subfr_length ], psPLC->subfr_length );
-
- if( silk_RSHIFT( energy1, shift2 ) < silk_RSHIFT( energy2, shift1 ) ) {
- /* First sub-frame has lowest energy */
- rand_ptr = &psDec->exc_Q14[ silk_max_int( 0, ( psPLC->nb_subfr - 1 ) * psPLC->subfr_length - RAND_BUF_SIZE ) ];
- } else {
- /* Second sub-frame has lowest energy */
- rand_ptr = &psDec->exc_Q14[ silk_max_int( 0, psPLC->nb_subfr * psPLC->subfr_length - RAND_BUF_SIZE ) ];
- }
-
- /* Set up Gain to random noise component */
- B_Q14 = psPLC->LTPCoef_Q14;
- rand_scale_Q14 = psPLC->randScale_Q14;
-
- /* Set up attenuation gains */
- harm_Gain_Q15 = HARM_ATT_Q15[ silk_min_int( NB_ATT - 1, psDec->lossCnt ) ];
- if( psDec->prevSignalType == TYPE_VOICED ) {
- rand_Gain_Q15 = PLC_RAND_ATTENUATE_V_Q15[ silk_min_int( NB_ATT - 1, psDec->lossCnt ) ];
- } else {
- rand_Gain_Q15 = PLC_RAND_ATTENUATE_UV_Q15[ silk_min_int( NB_ATT - 1, psDec->lossCnt ) ];
- }
-
- /* LPC concealment. Apply BWE to previous LPC */
- silk_bwexpander( psPLC->prevLPC_Q12, psDec->LPC_order, SILK_FIX_CONST( BWE_COEF, 16 ) );
-
- /* Preload LPC coeficients to array on stack. Gives small performance gain */
- silk_memcpy( A_Q12, psPLC->prevLPC_Q12, psDec->LPC_order * sizeof( opus_int16 ) );
-
- /* First Lost frame */
- if( psDec->lossCnt == 0 ) {
- rand_scale_Q14 = 1 << 14;
-
- /* Reduce random noise Gain for voiced frames */
- if( psDec->prevSignalType == TYPE_VOICED ) {
- for( i = 0; i < LTP_ORDER; i++ ) {
- rand_scale_Q14 -= B_Q14[ i ];
- }
- rand_scale_Q14 = silk_max_16( 3277, rand_scale_Q14 ); /* 0.2 */
- rand_scale_Q14 = (opus_int16)silk_RSHIFT( silk_SMULBB( rand_scale_Q14, psPLC->prevLTP_scale_Q14 ), 14 );
- } else {
- /* Reduce random noise for unvoiced frames with high LPC gain */
- opus_int32 invGain_Q30, down_scale_Q30;
-
- invGain_Q30 = silk_LPC_inverse_pred_gain( psPLC->prevLPC_Q12, psDec->LPC_order );
-
- down_scale_Q30 = silk_min_32( silk_RSHIFT( (opus_int32)1 << 30, LOG2_INV_LPC_GAIN_HIGH_THRES ), invGain_Q30 );
- down_scale_Q30 = silk_max_32( silk_RSHIFT( (opus_int32)1 << 30, LOG2_INV_LPC_GAIN_LOW_THRES ), down_scale_Q30 );
- down_scale_Q30 = silk_LSHIFT( down_scale_Q30, LOG2_INV_LPC_GAIN_HIGH_THRES );
-
- rand_Gain_Q15 = silk_RSHIFT( silk_SMULWB( down_scale_Q30, rand_Gain_Q15 ), 14 );
- }
- }
-
- rand_seed = psPLC->rand_seed;
- lag = silk_RSHIFT_ROUND( psPLC->pitchL_Q8, 8 );
- sLTP_buf_idx = psDec->ltp_mem_length;
-
- /* Rewhiten LTP state */
- idx = psDec->ltp_mem_length - lag - psDec->LPC_order - LTP_ORDER / 2;
- silk_assert( idx > 0 );
- silk_LPC_analysis_filter( &sLTP[ idx ], &psDec->outBuf[ idx ], A_Q12, psDec->ltp_mem_length - idx, psDec->LPC_order );
- /* Scale LTP state */
- inv_gain_Q30 = silk_INVERSE32_varQ( psPLC->prevGain_Q16[ 1 ], 46 );
- inv_gain_Q30 = silk_min( inv_gain_Q30, silk_int32_MAX >> 1 );
- for( i = idx + psDec->LPC_order; i < psDec->ltp_mem_length; i++ ) {
- sLTP_Q14[ i ] = silk_SMULWB( inv_gain_Q30, sLTP[ i ] );
- }
-
- /***************************/
- /* LTP synthesis filtering */
- /***************************/
- for( k = 0; k < psDec->nb_subfr; k++ ) {
- /* Set up pointer */
- pred_lag_ptr = &sLTP_Q14[ sLTP_buf_idx - lag + LTP_ORDER / 2 ];
- for( i = 0; i < psDec->subfr_length; i++ ) {
- /* Unrolled loop */
- /* Avoids introducing a bias because silk_SMLAWB() always rounds to -inf */
- LTP_pred_Q12 = 2;
- LTP_pred_Q12 = silk_SMLAWB( LTP_pred_Q12, pred_lag_ptr[ 0 ], B_Q14[ 0 ] );
- LTP_pred_Q12 = silk_SMLAWB( LTP_pred_Q12, pred_lag_ptr[ -1 ], B_Q14[ 1 ] );
- LTP_pred_Q12 = silk_SMLAWB( LTP_pred_Q12, pred_lag_ptr[ -2 ], B_Q14[ 2 ] );
- LTP_pred_Q12 = silk_SMLAWB( LTP_pred_Q12, pred_lag_ptr[ -3 ], B_Q14[ 3 ] );
- LTP_pred_Q12 = silk_SMLAWB( LTP_pred_Q12, pred_lag_ptr[ -4 ], B_Q14[ 4 ] );
- pred_lag_ptr++;
-
- /* Generate LPC excitation */
- rand_seed = silk_RAND( rand_seed );
- idx = silk_RSHIFT( rand_seed, 25 ) & RAND_BUF_MASK;
- sLTP_Q14[ sLTP_buf_idx ] = silk_LSHIFT32( silk_SMLAWB( LTP_pred_Q12, rand_ptr[ idx ], rand_scale_Q14 ), 2 );
- sLTP_buf_idx++;
- }
-
- /* Gradually reduce LTP gain */
- for( j = 0; j < LTP_ORDER; j++ ) {
- B_Q14[ j ] = silk_RSHIFT( silk_SMULBB( harm_Gain_Q15, B_Q14[ j ] ), 15 );
- }
- /* Gradually reduce excitation gain */
- rand_scale_Q14 = silk_RSHIFT( silk_SMULBB( rand_scale_Q14, rand_Gain_Q15 ), 15 );
-
- /* Slowly increase pitch lag */
- psPLC->pitchL_Q8 = silk_SMLAWB( psPLC->pitchL_Q8, psPLC->pitchL_Q8, PITCH_DRIFT_FAC_Q16 );
- psPLC->pitchL_Q8 = silk_min_32( psPLC->pitchL_Q8, silk_LSHIFT( silk_SMULBB( MAX_PITCH_LAG_MS, psDec->fs_kHz ), 8 ) );
- lag = silk_RSHIFT_ROUND( psPLC->pitchL_Q8, 8 );
- }
-
- /***************************/
- /* LPC synthesis filtering */
- /***************************/
- sLPC_Q14_ptr = &sLTP_Q14[ psDec->ltp_mem_length - MAX_LPC_ORDER ];
-
- /* Copy LPC state */
- silk_memcpy( sLPC_Q14_ptr, psDec->sLPC_Q14_buf, MAX_LPC_ORDER * sizeof( opus_int32 ) );
-
- silk_assert( psDec->LPC_order >= 10 ); /* check that unrolling works */
- for( i = 0; i < psDec->frame_length; i++ ) {
- /* partly unrolled */
- /* Avoids introducing a bias because silk_SMLAWB() always rounds to -inf */
- LPC_pred_Q10 = silk_RSHIFT( psDec->LPC_order, 1 );
- LPC_pred_Q10 = silk_SMLAWB( LPC_pred_Q10, sLPC_Q14_ptr[ MAX_LPC_ORDER + i - 1 ], A_Q12[ 0 ] );
- LPC_pred_Q10 = silk_SMLAWB( LPC_pred_Q10, sLPC_Q14_ptr[ MAX_LPC_ORDER + i - 2 ], A_Q12[ 1 ] );
- LPC_pred_Q10 = silk_SMLAWB( LPC_pred_Q10, sLPC_Q14_ptr[ MAX_LPC_ORDER + i - 3 ], A_Q12[ 2 ] );
- LPC_pred_Q10 = silk_SMLAWB( LPC_pred_Q10, sLPC_Q14_ptr[ MAX_LPC_ORDER + i - 4 ], A_Q12[ 3 ] );
- LPC_pred_Q10 = silk_SMLAWB( LPC_pred_Q10, sLPC_Q14_ptr[ MAX_LPC_ORDER + i - 5 ], A_Q12[ 4 ] );
- LPC_pred_Q10 = silk_SMLAWB( LPC_pred_Q10, sLPC_Q14_ptr[ MAX_LPC_ORDER + i - 6 ], A_Q12[ 5 ] );
- LPC_pred_Q10 = silk_SMLAWB( LPC_pred_Q10, sLPC_Q14_ptr[ MAX_LPC_ORDER + i - 7 ], A_Q12[ 6 ] );
- LPC_pred_Q10 = silk_SMLAWB( LPC_pred_Q10, sLPC_Q14_ptr[ MAX_LPC_ORDER + i - 8 ], A_Q12[ 7 ] );
- LPC_pred_Q10 = silk_SMLAWB( LPC_pred_Q10, sLPC_Q14_ptr[ MAX_LPC_ORDER + i - 9 ], A_Q12[ 8 ] );
- LPC_pred_Q10 = silk_SMLAWB( LPC_pred_Q10, sLPC_Q14_ptr[ MAX_LPC_ORDER + i - 10 ], A_Q12[ 9 ] );
- for( j = 10; j < psDec->LPC_order; j++ ) {
- LPC_pred_Q10 = silk_SMLAWB( LPC_pred_Q10, sLPC_Q14_ptr[ MAX_LPC_ORDER + i - j - 1 ], A_Q12[ j ] );
- }
-
- /* Add prediction to LPC excitation */
- sLPC_Q14_ptr[ MAX_LPC_ORDER + i ] = silk_ADD_LSHIFT32( sLPC_Q14_ptr[ MAX_LPC_ORDER + i ], LPC_pred_Q10, 4 );
-
- /* Scale with Gain */
- frame[ i ] = (opus_int16)silk_SAT16( silk_SAT16( silk_RSHIFT_ROUND( silk_SMULWW( sLPC_Q14_ptr[ MAX_LPC_ORDER + i ], prevGain_Q10[ 1 ] ), 8 ) ) );
- }
-
- /* Save LPC state */
- silk_memcpy( psDec->sLPC_Q14_buf, &sLPC_Q14_ptr[ psDec->frame_length ], MAX_LPC_ORDER * sizeof( opus_int32 ) );
-
- /**************************************/
- /* Update states */
- /**************************************/
- psPLC->rand_seed = rand_seed;
- psPLC->randScale_Q14 = rand_scale_Q14;
- for( i = 0; i < MAX_NB_SUBFR; i++ ) {
- psDecCtrl->pitchL[ i ] = lag;
- }
- RESTORE_STACK;
-}
-
-/* Glues concealed frames with new good received frames */
-void silk_PLC_glue_frames(
- silk_decoder_state *psDec, /* I/O decoder state */
- opus_int16 frame[], /* I/O signal */
- opus_int length /* I length of signal */
-)
-{
- opus_int i, energy_shift;
- opus_int32 energy;
- silk_PLC_struct *psPLC;
- psPLC = &psDec->sPLC;
-
- if( psDec->lossCnt ) {
- /* Calculate energy in concealed residual */
- silk_sum_sqr_shift( &psPLC->conc_energy, &psPLC->conc_energy_shift, frame, length );
-
- psPLC->last_frame_lost = 1;
- } else {
- if( psDec->sPLC.last_frame_lost ) {
- /* Calculate residual in decoded signal if last frame was lost */
- silk_sum_sqr_shift( &energy, &energy_shift, frame, length );
-
- /* Normalize energies */
- if( energy_shift > psPLC->conc_energy_shift ) {
- psPLC->conc_energy = silk_RSHIFT( psPLC->conc_energy, energy_shift - psPLC->conc_energy_shift );
- } else if( energy_shift < psPLC->conc_energy_shift ) {
- energy = silk_RSHIFT( energy, psPLC->conc_energy_shift - energy_shift );
- }
-
- /* Fade in the energy difference */
- if( energy > psPLC->conc_energy ) {
- opus_int32 frac_Q24, LZ;
- opus_int32 gain_Q16, slope_Q16;
-
- LZ = silk_CLZ32( psPLC->conc_energy );
- LZ = LZ - 1;
- psPLC->conc_energy = silk_LSHIFT( psPLC->conc_energy, LZ );
- energy = silk_RSHIFT( energy, silk_max_32( 24 - LZ, 0 ) );
-
- frac_Q24 = silk_DIV32( psPLC->conc_energy, silk_max( energy, 1 ) );
-
- gain_Q16 = silk_LSHIFT( silk_SQRT_APPROX( frac_Q24 ), 4 );
- slope_Q16 = silk_DIV32_16( ( (opus_int32)1 << 16 ) - gain_Q16, length );
- /* Make slope 4x steeper to avoid missing onsets after DTX */
- slope_Q16 = silk_LSHIFT( slope_Q16, 2 );
-
- for( i = 0; i < length; i++ ) {
- frame[ i ] = silk_SMULWB( gain_Q16, frame[ i ] );
- gain_Q16 += slope_Q16;
- if( gain_Q16 > (opus_int32)1 << 16 ) {
- break;
- }
- }
- }
- }
- psPLC->last_frame_lost = 0;
- }
-}