summaryrefslogtreecommitdiffstats
path: root/lib/rbcodec/codecs/libopus/silk/PLC.c
diff options
context:
space:
mode:
Diffstat (limited to 'lib/rbcodec/codecs/libopus/silk/PLC.c')
-rw-r--r--lib/rbcodec/codecs/libopus/silk/PLC.c423
1 files changed, 423 insertions, 0 deletions
diff --git a/lib/rbcodec/codecs/libopus/silk/PLC.c b/lib/rbcodec/codecs/libopus/silk/PLC.c
new file mode 100644
index 0000000000..08ae5b7617
--- /dev/null
+++ b/lib/rbcodec/codecs/libopus/silk/PLC.c
@@ -0,0 +1,423 @@
+/***********************************************************************
+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 "opus_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 recieved 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;
+ }
+}