Chris@69: /***********************************************************************
Chris@69: Copyright (c) 2006-2011, Skype Limited. All rights reserved.
Chris@69: Redistribution and use in source and binary forms, with or without
Chris@69: modification, are permitted provided that the following conditions
Chris@69: are met:
Chris@69: - Redistributions of source code must retain the above copyright notice,
Chris@69: this list of conditions and the following disclaimer.
Chris@69: - Redistributions in binary form must reproduce the above copyright
Chris@69: notice, this list of conditions and the following disclaimer in the
Chris@69: documentation and/or other materials provided with the distribution.
Chris@69: - Neither the name of Internet Society, IETF or IETF Trust, nor the
Chris@69: names of specific contributors, may be used to endorse or promote
Chris@69: products derived from this software without specific prior written
Chris@69: permission.
Chris@69: THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
Chris@69: AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
Chris@69: IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
Chris@69: ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
Chris@69: LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
Chris@69: CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
Chris@69: SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
Chris@69: INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
Chris@69: CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
Chris@69: ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
Chris@69: POSSIBILITY OF SUCH DAMAGE.
Chris@69: ***********************************************************************/
Chris@69: 
Chris@69: #ifdef HAVE_CONFIG_H
Chris@69: #include "config.h"
Chris@69: #endif
Chris@69: 
Chris@69: #include "main.h"
Chris@69: #include "stack_alloc.h"
Chris@69: #include "PLC.h"
Chris@69: 
Chris@69: #define NB_ATT 2
Chris@69: static const opus_int16 HARM_ATT_Q15[NB_ATT]              = { 32440, 31130 }; /* 0.99, 0.95 */
Chris@69: static const opus_int16 PLC_RAND_ATTENUATE_V_Q15[NB_ATT]  = { 31130, 26214 }; /* 0.95, 0.8 */
Chris@69: static const opus_int16 PLC_RAND_ATTENUATE_UV_Q15[NB_ATT] = { 32440, 29491 }; /* 0.99, 0.9 */
Chris@69: 
Chris@69: static OPUS_INLINE void silk_PLC_update(
Chris@69:     silk_decoder_state                  *psDec,             /* I/O Decoder state        */
Chris@69:     silk_decoder_control                *psDecCtrl          /* I/O Decoder control      */
Chris@69: );
Chris@69: 
Chris@69: static OPUS_INLINE void silk_PLC_conceal(
Chris@69:     silk_decoder_state                  *psDec,             /* I/O Decoder state        */
Chris@69:     silk_decoder_control                *psDecCtrl,         /* I/O Decoder control      */
Chris@69:     opus_int16                          frame[],            /* O LPC residual signal    */
Chris@69:     int                                 arch                /* I  Run-time architecture */
Chris@69: );
Chris@69: 
Chris@69: 
Chris@69: void silk_PLC_Reset(
Chris@69:     silk_decoder_state                  *psDec              /* I/O Decoder state        */
Chris@69: )
Chris@69: {
Chris@69:     psDec->sPLC.pitchL_Q8 = silk_LSHIFT( psDec->frame_length, 8 - 1 );
Chris@69:     psDec->sPLC.prevGain_Q16[ 0 ] = SILK_FIX_CONST( 1, 16 );
Chris@69:     psDec->sPLC.prevGain_Q16[ 1 ] = SILK_FIX_CONST( 1, 16 );
Chris@69:     psDec->sPLC.subfr_length = 20;
Chris@69:     psDec->sPLC.nb_subfr = 2;
Chris@69: }
Chris@69: 
Chris@69: void silk_PLC(
Chris@69:     silk_decoder_state                  *psDec,             /* I/O Decoder state        */
Chris@69:     silk_decoder_control                *psDecCtrl,         /* I/O Decoder control      */
Chris@69:     opus_int16                          frame[],            /* I/O  signal              */
Chris@69:     opus_int                            lost,               /* I Loss flag              */
Chris@69:     int                                 arch                /* I Run-time architecture  */
Chris@69: )
Chris@69: {
Chris@69:     /* PLC control function */
Chris@69:     if( psDec->fs_kHz != psDec->sPLC.fs_kHz ) {
Chris@69:         silk_PLC_Reset( psDec );
Chris@69:         psDec->sPLC.fs_kHz = psDec->fs_kHz;
Chris@69:     }
Chris@69: 
Chris@69:     if( lost ) {
Chris@69:         /****************************/
Chris@69:         /* Generate Signal          */
Chris@69:         /****************************/
Chris@69:         silk_PLC_conceal( psDec, psDecCtrl, frame, arch );
Chris@69: 
Chris@69:         psDec->lossCnt++;
Chris@69:     } else {
Chris@69:         /****************************/
Chris@69:         /* Update state             */
Chris@69:         /****************************/
Chris@69:         silk_PLC_update( psDec, psDecCtrl );
Chris@69:     }
Chris@69: }
Chris@69: 
Chris@69: /**************************************************/
Chris@69: /* Update state of PLC                            */
Chris@69: /**************************************************/
Chris@69: static OPUS_INLINE void silk_PLC_update(
Chris@69:     silk_decoder_state                  *psDec,             /* I/O Decoder state        */
Chris@69:     silk_decoder_control                *psDecCtrl          /* I/O Decoder control      */
Chris@69: )
Chris@69: {
Chris@69:     opus_int32 LTP_Gain_Q14, temp_LTP_Gain_Q14;
Chris@69:     opus_int   i, j;
Chris@69:     silk_PLC_struct *psPLC;
Chris@69: 
Chris@69:     psPLC = &psDec->sPLC;
Chris@69: 
Chris@69:     /* Update parameters used in case of packet loss */
Chris@69:     psDec->prevSignalType = psDec->indices.signalType;
Chris@69:     LTP_Gain_Q14 = 0;
Chris@69:     if( psDec->indices.signalType == TYPE_VOICED ) {
Chris@69:         /* Find the parameters for the last subframe which contains a pitch pulse */
Chris@69:         for( j = 0; j * psDec->subfr_length < psDecCtrl->pitchL[ psDec->nb_subfr - 1 ]; j++ ) {
Chris@69:             if( j == psDec->nb_subfr ) {
Chris@69:                 break;
Chris@69:             }
Chris@69:             temp_LTP_Gain_Q14 = 0;
Chris@69:             for( i = 0; i < LTP_ORDER; i++ ) {
Chris@69:                 temp_LTP_Gain_Q14 += psDecCtrl->LTPCoef_Q14[ ( psDec->nb_subfr - 1 - j ) * LTP_ORDER  + i ];
Chris@69:             }
Chris@69:             if( temp_LTP_Gain_Q14 > LTP_Gain_Q14 ) {
Chris@69:                 LTP_Gain_Q14 = temp_LTP_Gain_Q14;
Chris@69:                 silk_memcpy( psPLC->LTPCoef_Q14,
Chris@69:                     &psDecCtrl->LTPCoef_Q14[ silk_SMULBB( psDec->nb_subfr - 1 - j, LTP_ORDER ) ],
Chris@69:                     LTP_ORDER * sizeof( opus_int16 ) );
Chris@69: 
Chris@69:                 psPLC->pitchL_Q8 = silk_LSHIFT( psDecCtrl->pitchL[ psDec->nb_subfr - 1 - j ], 8 );
Chris@69:             }
Chris@69:         }
Chris@69: 
Chris@69:         silk_memset( psPLC->LTPCoef_Q14, 0, LTP_ORDER * sizeof( opus_int16 ) );
Chris@69:         psPLC->LTPCoef_Q14[ LTP_ORDER / 2 ] = LTP_Gain_Q14;
Chris@69: 
Chris@69:         /* Limit LT coefs */
Chris@69:         if( LTP_Gain_Q14 < V_PITCH_GAIN_START_MIN_Q14 ) {
Chris@69:             opus_int   scale_Q10;
Chris@69:             opus_int32 tmp;
Chris@69: 
Chris@69:             tmp = silk_LSHIFT( V_PITCH_GAIN_START_MIN_Q14, 10 );
Chris@69:             scale_Q10 = silk_DIV32( tmp, silk_max( LTP_Gain_Q14, 1 ) );
Chris@69:             for( i = 0; i < LTP_ORDER; i++ ) {
Chris@69:                 psPLC->LTPCoef_Q14[ i ] = silk_RSHIFT( silk_SMULBB( psPLC->LTPCoef_Q14[ i ], scale_Q10 ), 10 );
Chris@69:             }
Chris@69:         } else if( LTP_Gain_Q14 > V_PITCH_GAIN_START_MAX_Q14 ) {
Chris@69:             opus_int   scale_Q14;
Chris@69:             opus_int32 tmp;
Chris@69: 
Chris@69:             tmp = silk_LSHIFT( V_PITCH_GAIN_START_MAX_Q14, 14 );
Chris@69:             scale_Q14 = silk_DIV32( tmp, silk_max( LTP_Gain_Q14, 1 ) );
Chris@69:             for( i = 0; i < LTP_ORDER; i++ ) {
Chris@69:                 psPLC->LTPCoef_Q14[ i ] = silk_RSHIFT( silk_SMULBB( psPLC->LTPCoef_Q14[ i ], scale_Q14 ), 14 );
Chris@69:             }
Chris@69:         }
Chris@69:     } else {
Chris@69:         psPLC->pitchL_Q8 = silk_LSHIFT( silk_SMULBB( psDec->fs_kHz, 18 ), 8 );
Chris@69:         silk_memset( psPLC->LTPCoef_Q14, 0, LTP_ORDER * sizeof( opus_int16 ));
Chris@69:     }
Chris@69: 
Chris@69:     /* Save LPC coeficients */
Chris@69:     silk_memcpy( psPLC->prevLPC_Q12, psDecCtrl->PredCoef_Q12[ 1 ], psDec->LPC_order * sizeof( opus_int16 ) );
Chris@69:     psPLC->prevLTP_scale_Q14 = psDecCtrl->LTP_scale_Q14;
Chris@69: 
Chris@69:     /* Save last two gains */
Chris@69:     silk_memcpy( psPLC->prevGain_Q16, &psDecCtrl->Gains_Q16[ psDec->nb_subfr - 2 ], 2 * sizeof( opus_int32 ) );
Chris@69: 
Chris@69:     psPLC->subfr_length = psDec->subfr_length;
Chris@69:     psPLC->nb_subfr = psDec->nb_subfr;
Chris@69: }
Chris@69: 
Chris@69: static OPUS_INLINE void silk_PLC_energy(opus_int32 *energy1, opus_int *shift1, opus_int32 *energy2, opus_int *shift2,
Chris@69:       const opus_int32 *exc_Q14, const opus_int32 *prevGain_Q10, int subfr_length, int nb_subfr)
Chris@69: {
Chris@69:     int i, k;
Chris@69:     VARDECL( opus_int16, exc_buf );
Chris@69:     opus_int16 *exc_buf_ptr;
Chris@69:     SAVE_STACK;
Chris@69:     ALLOC( exc_buf, 2*subfr_length, opus_int16 );
Chris@69:     /* Find random noise component */
Chris@69:     /* Scale previous excitation signal */
Chris@69:     exc_buf_ptr = exc_buf;
Chris@69:     for( k = 0; k < 2; k++ ) {
Chris@69:         for( i = 0; i < subfr_length; i++ ) {
Chris@69:             exc_buf_ptr[ i ] = (opus_int16)silk_SAT16( silk_RSHIFT(
Chris@69:                 silk_SMULWW( exc_Q14[ i + ( k + nb_subfr - 2 ) * subfr_length ], prevGain_Q10[ k ] ), 8 ) );
Chris@69:         }
Chris@69:         exc_buf_ptr += subfr_length;
Chris@69:     }
Chris@69:     /* Find the subframe with lowest energy of the last two and use that as random noise generator */
Chris@69:     silk_sum_sqr_shift( energy1, shift1, exc_buf,                  subfr_length );
Chris@69:     silk_sum_sqr_shift( energy2, shift2, &exc_buf[ subfr_length ], subfr_length );
Chris@69:     RESTORE_STACK;
Chris@69: }
Chris@69: 
Chris@69: static OPUS_INLINE void silk_PLC_conceal(
Chris@69:     silk_decoder_state                  *psDec,             /* I/O Decoder state        */
Chris@69:     silk_decoder_control                *psDecCtrl,         /* I/O Decoder control      */
Chris@69:     opus_int16                          frame[],            /* O LPC residual signal    */
Chris@69:     int                                 arch                /* I Run-time architecture  */
Chris@69: )
Chris@69: {
Chris@69:     opus_int   i, j, k;
Chris@69:     opus_int   lag, idx, sLTP_buf_idx, shift1, shift2;
Chris@69:     opus_int32 rand_seed, harm_Gain_Q15, rand_Gain_Q15, inv_gain_Q30;
Chris@69:     opus_int32 energy1, energy2, *rand_ptr, *pred_lag_ptr;
Chris@69:     opus_int32 LPC_pred_Q10, LTP_pred_Q12;
Chris@69:     opus_int16 rand_scale_Q14;
Chris@69:     opus_int16 *B_Q14;
Chris@69:     opus_int32 *sLPC_Q14_ptr;
Chris@69:     opus_int16 A_Q12[ MAX_LPC_ORDER ];
Chris@69: #ifdef SMALL_FOOTPRINT
Chris@69:     opus_int16 *sLTP;
Chris@69: #else
Chris@69:     VARDECL( opus_int16, sLTP );
Chris@69: #endif
Chris@69:     VARDECL( opus_int32, sLTP_Q14 );
Chris@69:     silk_PLC_struct *psPLC = &psDec->sPLC;
Chris@69:     opus_int32 prevGain_Q10[2];
Chris@69:     SAVE_STACK;
Chris@69: 
Chris@69:     ALLOC( sLTP_Q14, psDec->ltp_mem_length + psDec->frame_length, opus_int32 );
Chris@69: #ifdef SMALL_FOOTPRINT
Chris@69:     /* Ugly hack that breaks aliasing rules to save stack: put sLTP at the very end of sLTP_Q14. */
Chris@69:     sLTP = ((opus_int16*)&sLTP_Q14[psDec->ltp_mem_length + psDec->frame_length])-psDec->ltp_mem_length;
Chris@69: #else
Chris@69:     ALLOC( sLTP, psDec->ltp_mem_length, opus_int16 );
Chris@69: #endif
Chris@69: 
Chris@69:     prevGain_Q10[0] = silk_RSHIFT( psPLC->prevGain_Q16[ 0 ], 6);
Chris@69:     prevGain_Q10[1] = silk_RSHIFT( psPLC->prevGain_Q16[ 1 ], 6);
Chris@69: 
Chris@69:     if( psDec->first_frame_after_reset ) {
Chris@69:        silk_memset( psPLC->prevLPC_Q12, 0, sizeof( psPLC->prevLPC_Q12 ) );
Chris@69:     }
Chris@69: 
Chris@69:     silk_PLC_energy(&energy1, &shift1, &energy2, &shift2, psDec->exc_Q14, prevGain_Q10, psDec->subfr_length, psDec->nb_subfr);
Chris@69: 
Chris@69:     if( silk_RSHIFT( energy1, shift2 ) < silk_RSHIFT( energy2, shift1 ) ) {
Chris@69:         /* First sub-frame has lowest energy */
Chris@69:         rand_ptr = &psDec->exc_Q14[ silk_max_int( 0, ( psPLC->nb_subfr - 1 ) * psPLC->subfr_length - RAND_BUF_SIZE ) ];
Chris@69:     } else {
Chris@69:         /* Second sub-frame has lowest energy */
Chris@69:         rand_ptr = &psDec->exc_Q14[ silk_max_int( 0, psPLC->nb_subfr * psPLC->subfr_length - RAND_BUF_SIZE ) ];
Chris@69:     }
Chris@69: 
Chris@69:     /* Set up Gain to random noise component */
Chris@69:     B_Q14          = psPLC->LTPCoef_Q14;
Chris@69:     rand_scale_Q14 = psPLC->randScale_Q14;
Chris@69: 
Chris@69:     /* Set up attenuation gains */
Chris@69:     harm_Gain_Q15 = HARM_ATT_Q15[ silk_min_int( NB_ATT - 1, psDec->lossCnt ) ];
Chris@69:     if( psDec->prevSignalType == TYPE_VOICED ) {
Chris@69:         rand_Gain_Q15 = PLC_RAND_ATTENUATE_V_Q15[  silk_min_int( NB_ATT - 1, psDec->lossCnt ) ];
Chris@69:     } else {
Chris@69:         rand_Gain_Q15 = PLC_RAND_ATTENUATE_UV_Q15[ silk_min_int( NB_ATT - 1, psDec->lossCnt ) ];
Chris@69:     }
Chris@69: 
Chris@69:     /* LPC concealment. Apply BWE to previous LPC */
Chris@69:     silk_bwexpander( psPLC->prevLPC_Q12, psDec->LPC_order, SILK_FIX_CONST( BWE_COEF, 16 ) );
Chris@69: 
Chris@69:     /* Preload LPC coeficients to array on stack. Gives small performance gain */
Chris@69:     silk_memcpy( A_Q12, psPLC->prevLPC_Q12, psDec->LPC_order * sizeof( opus_int16 ) );
Chris@69: 
Chris@69:     /* First Lost frame */
Chris@69:     if( psDec->lossCnt == 0 ) {
Chris@69:         rand_scale_Q14 = 1 << 14;
Chris@69: 
Chris@69:         /* Reduce random noise Gain for voiced frames */
Chris@69:         if( psDec->prevSignalType == TYPE_VOICED ) {
Chris@69:             for( i = 0; i < LTP_ORDER; i++ ) {
Chris@69:                 rand_scale_Q14 -= B_Q14[ i ];
Chris@69:             }
Chris@69:             rand_scale_Q14 = silk_max_16( 3277, rand_scale_Q14 ); /* 0.2 */
Chris@69:             rand_scale_Q14 = (opus_int16)silk_RSHIFT( silk_SMULBB( rand_scale_Q14, psPLC->prevLTP_scale_Q14 ), 14 );
Chris@69:         } else {
Chris@69:             /* Reduce random noise for unvoiced frames with high LPC gain */
Chris@69:             opus_int32 invGain_Q30, down_scale_Q30;
Chris@69: 
Chris@69:             invGain_Q30 = silk_LPC_inverse_pred_gain( psPLC->prevLPC_Q12, psDec->LPC_order, arch );
Chris@69: 
Chris@69:             down_scale_Q30 = silk_min_32( silk_RSHIFT( (opus_int32)1 << 30, LOG2_INV_LPC_GAIN_HIGH_THRES ), invGain_Q30 );
Chris@69:             down_scale_Q30 = silk_max_32( silk_RSHIFT( (opus_int32)1 << 30, LOG2_INV_LPC_GAIN_LOW_THRES ), down_scale_Q30 );
Chris@69:             down_scale_Q30 = silk_LSHIFT( down_scale_Q30, LOG2_INV_LPC_GAIN_HIGH_THRES );
Chris@69: 
Chris@69:             rand_Gain_Q15 = silk_RSHIFT( silk_SMULWB( down_scale_Q30, rand_Gain_Q15 ), 14 );
Chris@69:         }
Chris@69:     }
Chris@69: 
Chris@69:     rand_seed    = psPLC->rand_seed;
Chris@69:     lag          = silk_RSHIFT_ROUND( psPLC->pitchL_Q8, 8 );
Chris@69:     sLTP_buf_idx = psDec->ltp_mem_length;
Chris@69: 
Chris@69:     /* Rewhiten LTP state */
Chris@69:     idx = psDec->ltp_mem_length - lag - psDec->LPC_order - LTP_ORDER / 2;
Chris@69:     celt_assert( idx > 0 );
Chris@69:     silk_LPC_analysis_filter( &sLTP[ idx ], &psDec->outBuf[ idx ], A_Q12, psDec->ltp_mem_length - idx, psDec->LPC_order, arch );
Chris@69:     /* Scale LTP state */
Chris@69:     inv_gain_Q30 = silk_INVERSE32_varQ( psPLC->prevGain_Q16[ 1 ], 46 );
Chris@69:     inv_gain_Q30 = silk_min( inv_gain_Q30, silk_int32_MAX >> 1 );
Chris@69:     for( i = idx + psDec->LPC_order; i < psDec->ltp_mem_length; i++ ) {
Chris@69:         sLTP_Q14[ i ] = silk_SMULWB( inv_gain_Q30, sLTP[ i ] );
Chris@69:     }
Chris@69: 
Chris@69:     /***************************/
Chris@69:     /* LTP synthesis filtering */
Chris@69:     /***************************/
Chris@69:     for( k = 0; k < psDec->nb_subfr; k++ ) {
Chris@69:         /* Set up pointer */
Chris@69:         pred_lag_ptr = &sLTP_Q14[ sLTP_buf_idx - lag + LTP_ORDER / 2 ];
Chris@69:         for( i = 0; i < psDec->subfr_length; i++ ) {
Chris@69:             /* Unrolled loop */
Chris@69:             /* Avoids introducing a bias because silk_SMLAWB() always rounds to -inf */
Chris@69:             LTP_pred_Q12 = 2;
Chris@69:             LTP_pred_Q12 = silk_SMLAWB( LTP_pred_Q12, pred_lag_ptr[  0 ], B_Q14[ 0 ] );
Chris@69:             LTP_pred_Q12 = silk_SMLAWB( LTP_pred_Q12, pred_lag_ptr[ -1 ], B_Q14[ 1 ] );
Chris@69:             LTP_pred_Q12 = silk_SMLAWB( LTP_pred_Q12, pred_lag_ptr[ -2 ], B_Q14[ 2 ] );
Chris@69:             LTP_pred_Q12 = silk_SMLAWB( LTP_pred_Q12, pred_lag_ptr[ -3 ], B_Q14[ 3 ] );
Chris@69:             LTP_pred_Q12 = silk_SMLAWB( LTP_pred_Q12, pred_lag_ptr[ -4 ], B_Q14[ 4 ] );
Chris@69:             pred_lag_ptr++;
Chris@69: 
Chris@69:             /* Generate LPC excitation */
Chris@69:             rand_seed = silk_RAND( rand_seed );
Chris@69:             idx = silk_RSHIFT( rand_seed, 25 ) & RAND_BUF_MASK;
Chris@69:             sLTP_Q14[ sLTP_buf_idx ] = silk_LSHIFT32( silk_SMLAWB( LTP_pred_Q12, rand_ptr[ idx ], rand_scale_Q14 ), 2 );
Chris@69:             sLTP_buf_idx++;
Chris@69:         }
Chris@69: 
Chris@69:         /* Gradually reduce LTP gain */
Chris@69:         for( j = 0; j < LTP_ORDER; j++ ) {
Chris@69:             B_Q14[ j ] = silk_RSHIFT( silk_SMULBB( harm_Gain_Q15, B_Q14[ j ] ), 15 );
Chris@69:         }
Chris@69:         if ( psDec->indices.signalType != TYPE_NO_VOICE_ACTIVITY ) {
Chris@69:             /* Gradually reduce excitation gain */
Chris@69:             rand_scale_Q14 = silk_RSHIFT( silk_SMULBB( rand_scale_Q14, rand_Gain_Q15 ), 15 );
Chris@69:         }
Chris@69: 
Chris@69:         /* Slowly increase pitch lag */
Chris@69:         psPLC->pitchL_Q8 = silk_SMLAWB( psPLC->pitchL_Q8, psPLC->pitchL_Q8, PITCH_DRIFT_FAC_Q16 );
Chris@69:         psPLC->pitchL_Q8 = silk_min_32( psPLC->pitchL_Q8, silk_LSHIFT( silk_SMULBB( MAX_PITCH_LAG_MS, psDec->fs_kHz ), 8 ) );
Chris@69:         lag = silk_RSHIFT_ROUND( psPLC->pitchL_Q8, 8 );
Chris@69:     }
Chris@69: 
Chris@69:     /***************************/
Chris@69:     /* LPC synthesis filtering */
Chris@69:     /***************************/
Chris@69:     sLPC_Q14_ptr = &sLTP_Q14[ psDec->ltp_mem_length - MAX_LPC_ORDER ];
Chris@69: 
Chris@69:     /* Copy LPC state */
Chris@69:     silk_memcpy( sLPC_Q14_ptr, psDec->sLPC_Q14_buf, MAX_LPC_ORDER * sizeof( opus_int32 ) );
Chris@69: 
Chris@69:     celt_assert( psDec->LPC_order >= 10 ); /* check that unrolling works */
Chris@69:     for( i = 0; i < psDec->frame_length; i++ ) {
Chris@69:         /* partly unrolled */
Chris@69:         /* Avoids introducing a bias because silk_SMLAWB() always rounds to -inf */
Chris@69:         LPC_pred_Q10 = silk_RSHIFT( psDec->LPC_order, 1 );
Chris@69:         LPC_pred_Q10 = silk_SMLAWB( LPC_pred_Q10, sLPC_Q14_ptr[ MAX_LPC_ORDER + i -  1 ], A_Q12[ 0 ] );
Chris@69:         LPC_pred_Q10 = silk_SMLAWB( LPC_pred_Q10, sLPC_Q14_ptr[ MAX_LPC_ORDER + i -  2 ], A_Q12[ 1 ] );
Chris@69:         LPC_pred_Q10 = silk_SMLAWB( LPC_pred_Q10, sLPC_Q14_ptr[ MAX_LPC_ORDER + i -  3 ], A_Q12[ 2 ] );
Chris@69:         LPC_pred_Q10 = silk_SMLAWB( LPC_pred_Q10, sLPC_Q14_ptr[ MAX_LPC_ORDER + i -  4 ], A_Q12[ 3 ] );
Chris@69:         LPC_pred_Q10 = silk_SMLAWB( LPC_pred_Q10, sLPC_Q14_ptr[ MAX_LPC_ORDER + i -  5 ], A_Q12[ 4 ] );
Chris@69:         LPC_pred_Q10 = silk_SMLAWB( LPC_pred_Q10, sLPC_Q14_ptr[ MAX_LPC_ORDER + i -  6 ], A_Q12[ 5 ] );
Chris@69:         LPC_pred_Q10 = silk_SMLAWB( LPC_pred_Q10, sLPC_Q14_ptr[ MAX_LPC_ORDER + i -  7 ], A_Q12[ 6 ] );
Chris@69:         LPC_pred_Q10 = silk_SMLAWB( LPC_pred_Q10, sLPC_Q14_ptr[ MAX_LPC_ORDER + i -  8 ], A_Q12[ 7 ] );
Chris@69:         LPC_pred_Q10 = silk_SMLAWB( LPC_pred_Q10, sLPC_Q14_ptr[ MAX_LPC_ORDER + i -  9 ], A_Q12[ 8 ] );
Chris@69:         LPC_pred_Q10 = silk_SMLAWB( LPC_pred_Q10, sLPC_Q14_ptr[ MAX_LPC_ORDER + i - 10 ], A_Q12[ 9 ] );
Chris@69:         for( j = 10; j < psDec->LPC_order; j++ ) {
Chris@69:             LPC_pred_Q10 = silk_SMLAWB( LPC_pred_Q10, sLPC_Q14_ptr[ MAX_LPC_ORDER + i - j - 1 ], A_Q12[ j ] );
Chris@69:         }
Chris@69: 
Chris@69:         /* Add prediction to LPC excitation */
Chris@69:         sLPC_Q14_ptr[ MAX_LPC_ORDER + i ] = silk_ADD_SAT32( sLPC_Q14_ptr[ MAX_LPC_ORDER + i ],
Chris@69:                                             silk_LSHIFT_SAT32( LPC_pred_Q10, 4 ));
Chris@69: 
Chris@69:         /* Scale with Gain */
Chris@69:         frame[ i ] = (opus_int16)silk_SAT16( silk_SAT16( silk_RSHIFT_ROUND( silk_SMULWW( sLPC_Q14_ptr[ MAX_LPC_ORDER + i ], prevGain_Q10[ 1 ] ), 8 ) ) );
Chris@69:     }
Chris@69: 
Chris@69:     /* Save LPC state */
Chris@69:     silk_memcpy( psDec->sLPC_Q14_buf, &sLPC_Q14_ptr[ psDec->frame_length ], MAX_LPC_ORDER * sizeof( opus_int32 ) );
Chris@69: 
Chris@69:     /**************************************/
Chris@69:     /* Update states                      */
Chris@69:     /**************************************/
Chris@69:     psPLC->rand_seed     = rand_seed;
Chris@69:     psPLC->randScale_Q14 = rand_scale_Q14;
Chris@69:     for( i = 0; i < MAX_NB_SUBFR; i++ ) {
Chris@69:         psDecCtrl->pitchL[ i ] = lag;
Chris@69:     }
Chris@69:     RESTORE_STACK;
Chris@69: }
Chris@69: 
Chris@69: /* Glues concealed frames with new good received frames */
Chris@69: void silk_PLC_glue_frames(
Chris@69:     silk_decoder_state                  *psDec,             /* I/O decoder state        */
Chris@69:     opus_int16                          frame[],            /* I/O signal               */
Chris@69:     opus_int                            length              /* I length of signal       */
Chris@69: )
Chris@69: {
Chris@69:     opus_int   i, energy_shift;
Chris@69:     opus_int32 energy;
Chris@69:     silk_PLC_struct *psPLC;
Chris@69:     psPLC = &psDec->sPLC;
Chris@69: 
Chris@69:     if( psDec->lossCnt ) {
Chris@69:         /* Calculate energy in concealed residual */
Chris@69:         silk_sum_sqr_shift( &psPLC->conc_energy, &psPLC->conc_energy_shift, frame, length );
Chris@69: 
Chris@69:         psPLC->last_frame_lost = 1;
Chris@69:     } else {
Chris@69:         if( psDec->sPLC.last_frame_lost ) {
Chris@69:             /* Calculate residual in decoded signal if last frame was lost */
Chris@69:             silk_sum_sqr_shift( &energy, &energy_shift, frame, length );
Chris@69: 
Chris@69:             /* Normalize energies */
Chris@69:             if( energy_shift > psPLC->conc_energy_shift ) {
Chris@69:                 psPLC->conc_energy = silk_RSHIFT( psPLC->conc_energy, energy_shift - psPLC->conc_energy_shift );
Chris@69:             } else if( energy_shift < psPLC->conc_energy_shift ) {
Chris@69:                 energy = silk_RSHIFT( energy, psPLC->conc_energy_shift - energy_shift );
Chris@69:             }
Chris@69: 
Chris@69:             /* Fade in the energy difference */
Chris@69:             if( energy > psPLC->conc_energy ) {
Chris@69:                 opus_int32 frac_Q24, LZ;
Chris@69:                 opus_int32 gain_Q16, slope_Q16;
Chris@69: 
Chris@69:                 LZ = silk_CLZ32( psPLC->conc_energy );
Chris@69:                 LZ = LZ - 1;
Chris@69:                 psPLC->conc_energy = silk_LSHIFT( psPLC->conc_energy, LZ );
Chris@69:                 energy = silk_RSHIFT( energy, silk_max_32( 24 - LZ, 0 ) );
Chris@69: 
Chris@69:                 frac_Q24 = silk_DIV32( psPLC->conc_energy, silk_max( energy, 1 ) );
Chris@69: 
Chris@69:                 gain_Q16 = silk_LSHIFT( silk_SQRT_APPROX( frac_Q24 ), 4 );
Chris@69:                 slope_Q16 = silk_DIV32_16( ( (opus_int32)1 << 16 ) - gain_Q16, length );
Chris@69:                 /* Make slope 4x steeper to avoid missing onsets after DTX */
Chris@69:                 slope_Q16 = silk_LSHIFT( slope_Q16, 2 );
Chris@69: 
Chris@69:                 for( i = 0; i < length; i++ ) {
Chris@69:                     frame[ i ] = silk_SMULWB( gain_Q16, frame[ i ] );
Chris@69:                     gain_Q16 += slope_Q16;
Chris@69:                     if( gain_Q16 > (opus_int32)1 << 16 ) {
Chris@69:                         break;
Chris@69:                     }
Chris@69:                 }
Chris@69:             }
Chris@69:         }
Chris@69:         psPLC->last_frame_lost = 0;
Chris@69:     }
Chris@69: }