michael@0: /***********************************************************************
michael@0: Copyright (c) 2006-2011, Skype Limited. All rights reserved.
michael@0: Redistribution and use in source and binary forms, with or without
michael@0: modification, are permitted provided that the following conditions
michael@0: are met:
michael@0: - Redistributions of source code must retain the above copyright notice,
michael@0: this list of conditions and the following disclaimer.
michael@0: - Redistributions in binary form must reproduce the above copyright
michael@0: notice, this list of conditions and the following disclaimer in the
michael@0: documentation and/or other materials provided with the distribution.
michael@0: - Neither the name of Internet Society, IETF or IETF Trust, nor the
michael@0: names of specific contributors, may be used to endorse or promote
michael@0: products derived from this software without specific prior written
michael@0: permission.
michael@0: THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
michael@0: AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
michael@0: IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
michael@0: ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
michael@0: LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
michael@0: CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
michael@0: SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
michael@0: INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
michael@0: CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
michael@0: ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
michael@0: POSSIBILITY OF SUCH DAMAGE.
michael@0: ***********************************************************************/
michael@0: 
michael@0: #ifdef HAVE_CONFIG_H
michael@0: #include "config.h"
michael@0: #endif
michael@0: 
michael@0: #include "main.h"
michael@0: #include "stack_alloc.h"
michael@0: 
michael@0: /* Generates excitation for CNG LPC synthesis */
michael@0: static OPUS_INLINE void silk_CNG_exc(
michael@0:     opus_int32                       residual_Q10[],     /* O    CNG residual signal Q10                     */
michael@0:     opus_int32                       exc_buf_Q14[],      /* I    Random samples buffer Q10                   */
michael@0:     opus_int32                       Gain_Q16,           /* I    Gain to apply                               */
michael@0:     opus_int                         length,             /* I    Length                                      */
michael@0:     opus_int32                       *rand_seed          /* I/O  Seed to random index generator              */
michael@0: )
michael@0: {
michael@0:     opus_int32 seed;
michael@0:     opus_int   i, idx, exc_mask;
michael@0: 
michael@0:     exc_mask = CNG_BUF_MASK_MAX;
michael@0:     while( exc_mask > length ) {
michael@0:         exc_mask = silk_RSHIFT( exc_mask, 1 );
michael@0:     }
michael@0: 
michael@0:     seed = *rand_seed;
michael@0:     for( i = 0; i < length; i++ ) {
michael@0:         seed = silk_RAND( seed );
michael@0:         idx = (opus_int)( silk_RSHIFT( seed, 24 ) & exc_mask );
michael@0:         silk_assert( idx >= 0 );
michael@0:         silk_assert( idx <= CNG_BUF_MASK_MAX );
michael@0:         residual_Q10[ i ] = (opus_int16)silk_SAT16( silk_SMULWW( exc_buf_Q14[ idx ], Gain_Q16 >> 4 ) );
michael@0:     }
michael@0:     *rand_seed = seed;
michael@0: }
michael@0: 
michael@0: void silk_CNG_Reset(
michael@0:     silk_decoder_state          *psDec                          /* I/O  Decoder state                               */
michael@0: )
michael@0: {
michael@0:     opus_int i, NLSF_step_Q15, NLSF_acc_Q15;
michael@0: 
michael@0:     NLSF_step_Q15 = silk_DIV32_16( silk_int16_MAX, psDec->LPC_order + 1 );
michael@0:     NLSF_acc_Q15 = 0;
michael@0:     for( i = 0; i < psDec->LPC_order; i++ ) {
michael@0:         NLSF_acc_Q15 += NLSF_step_Q15;
michael@0:         psDec->sCNG.CNG_smth_NLSF_Q15[ i ] = NLSF_acc_Q15;
michael@0:     }
michael@0:     psDec->sCNG.CNG_smth_Gain_Q16 = 0;
michael@0:     psDec->sCNG.rand_seed = 3176576;
michael@0: }
michael@0: 
michael@0: /* Updates CNG estimate, and applies the CNG when packet was lost   */
michael@0: void silk_CNG(
michael@0:     silk_decoder_state          *psDec,                         /* I/O  Decoder state                               */
michael@0:     silk_decoder_control        *psDecCtrl,                     /* I/O  Decoder control                             */
michael@0:     opus_int16                  frame[],                        /* I/O  Signal                                      */
michael@0:     opus_int                    length                          /* I    Length of residual                          */
michael@0: )
michael@0: {
michael@0:     opus_int   i, subfr;
michael@0:     opus_int32 sum_Q6, max_Gain_Q16;
michael@0:     opus_int16 A_Q12[ MAX_LPC_ORDER ];
michael@0:     silk_CNG_struct *psCNG = &psDec->sCNG;
michael@0:     SAVE_STACK;
michael@0: 
michael@0:     if( psDec->fs_kHz != psCNG->fs_kHz ) {
michael@0:         /* Reset state */
michael@0:         silk_CNG_Reset( psDec );
michael@0: 
michael@0:         psCNG->fs_kHz = psDec->fs_kHz;
michael@0:     }
michael@0:     if( psDec->lossCnt == 0 && psDec->prevSignalType == TYPE_NO_VOICE_ACTIVITY ) {
michael@0:         /* Update CNG parameters */
michael@0: 
michael@0:         /* Smoothing of LSF's  */
michael@0:         for( i = 0; i < psDec->LPC_order; i++ ) {
michael@0:             psCNG->CNG_smth_NLSF_Q15[ i ] += silk_SMULWB( (opus_int32)psDec->prevNLSF_Q15[ i ] - (opus_int32)psCNG->CNG_smth_NLSF_Q15[ i ], CNG_NLSF_SMTH_Q16 );
michael@0:         }
michael@0:         /* Find the subframe with the highest gain */
michael@0:         max_Gain_Q16 = 0;
michael@0:         subfr        = 0;
michael@0:         for( i = 0; i < psDec->nb_subfr; i++ ) {
michael@0:             if( psDecCtrl->Gains_Q16[ i ] > max_Gain_Q16 ) {
michael@0:                 max_Gain_Q16 = psDecCtrl->Gains_Q16[ i ];
michael@0:                 subfr        = i;
michael@0:             }
michael@0:         }
michael@0:         /* Update CNG excitation buffer with excitation from this subframe */
michael@0:         silk_memmove( &psCNG->CNG_exc_buf_Q14[ psDec->subfr_length ], psCNG->CNG_exc_buf_Q14, ( psDec->nb_subfr - 1 ) * psDec->subfr_length * sizeof( opus_int32 ) );
michael@0:         silk_memcpy(   psCNG->CNG_exc_buf_Q14, &psDec->exc_Q14[ subfr * psDec->subfr_length ], psDec->subfr_length * sizeof( opus_int32 ) );
michael@0: 
michael@0:         /* Smooth gains */
michael@0:         for( i = 0; i < psDec->nb_subfr; i++ ) {
michael@0:             psCNG->CNG_smth_Gain_Q16 += silk_SMULWB( psDecCtrl->Gains_Q16[ i ] - psCNG->CNG_smth_Gain_Q16, CNG_GAIN_SMTH_Q16 );
michael@0:         }
michael@0:     }
michael@0: 
michael@0:     /* Add CNG when packet is lost or during DTX */
michael@0:     if( psDec->lossCnt ) {
michael@0:         VARDECL( opus_int32, CNG_sig_Q10 );
michael@0: 
michael@0:         ALLOC( CNG_sig_Q10, length + MAX_LPC_ORDER, opus_int32 );
michael@0: 
michael@0:         /* Generate CNG excitation */
michael@0:         silk_CNG_exc( CNG_sig_Q10 + MAX_LPC_ORDER, psCNG->CNG_exc_buf_Q14, psCNG->CNG_smth_Gain_Q16, length, &psCNG->rand_seed );
michael@0: 
michael@0:         /* Convert CNG NLSF to filter representation */
michael@0:         silk_NLSF2A( A_Q12, psCNG->CNG_smth_NLSF_Q15, psDec->LPC_order );
michael@0: 
michael@0:         /* Generate CNG signal, by synthesis filtering */
michael@0:         silk_memcpy( CNG_sig_Q10, psCNG->CNG_synth_state, MAX_LPC_ORDER * sizeof( opus_int32 ) );
michael@0:         for( i = 0; i < length; i++ ) {
michael@0:             silk_assert( psDec->LPC_order == 10 || psDec->LPC_order == 16 );
michael@0:             /* Avoids introducing a bias because silk_SMLAWB() always rounds to -inf */
michael@0:             sum_Q6 = silk_RSHIFT( psDec->LPC_order, 1 );
michael@0:             sum_Q6 = silk_SMLAWB( sum_Q6, CNG_sig_Q10[ MAX_LPC_ORDER + i -  1 ], A_Q12[ 0 ] );
michael@0:             sum_Q6 = silk_SMLAWB( sum_Q6, CNG_sig_Q10[ MAX_LPC_ORDER + i -  2 ], A_Q12[ 1 ] );
michael@0:             sum_Q6 = silk_SMLAWB( sum_Q6, CNG_sig_Q10[ MAX_LPC_ORDER + i -  3 ], A_Q12[ 2 ] );
michael@0:             sum_Q6 = silk_SMLAWB( sum_Q6, CNG_sig_Q10[ MAX_LPC_ORDER + i -  4 ], A_Q12[ 3 ] );
michael@0:             sum_Q6 = silk_SMLAWB( sum_Q6, CNG_sig_Q10[ MAX_LPC_ORDER + i -  5 ], A_Q12[ 4 ] );
michael@0:             sum_Q6 = silk_SMLAWB( sum_Q6, CNG_sig_Q10[ MAX_LPC_ORDER + i -  6 ], A_Q12[ 5 ] );
michael@0:             sum_Q6 = silk_SMLAWB( sum_Q6, CNG_sig_Q10[ MAX_LPC_ORDER + i -  7 ], A_Q12[ 6 ] );
michael@0:             sum_Q6 = silk_SMLAWB( sum_Q6, CNG_sig_Q10[ MAX_LPC_ORDER + i -  8 ], A_Q12[ 7 ] );
michael@0:             sum_Q6 = silk_SMLAWB( sum_Q6, CNG_sig_Q10[ MAX_LPC_ORDER + i -  9 ], A_Q12[ 8 ] );
michael@0:             sum_Q6 = silk_SMLAWB( sum_Q6, CNG_sig_Q10[ MAX_LPC_ORDER + i - 10 ], A_Q12[ 9 ] );
michael@0:             if( psDec->LPC_order == 16 ) {
michael@0:                 sum_Q6 = silk_SMLAWB( sum_Q6, CNG_sig_Q10[ MAX_LPC_ORDER + i - 11 ], A_Q12[ 10 ] );
michael@0:                 sum_Q6 = silk_SMLAWB( sum_Q6, CNG_sig_Q10[ MAX_LPC_ORDER + i - 12 ], A_Q12[ 11 ] );
michael@0:                 sum_Q6 = silk_SMLAWB( sum_Q6, CNG_sig_Q10[ MAX_LPC_ORDER + i - 13 ], A_Q12[ 12 ] );
michael@0:                 sum_Q6 = silk_SMLAWB( sum_Q6, CNG_sig_Q10[ MAX_LPC_ORDER + i - 14 ], A_Q12[ 13 ] );
michael@0:                 sum_Q6 = silk_SMLAWB( sum_Q6, CNG_sig_Q10[ MAX_LPC_ORDER + i - 15 ], A_Q12[ 14 ] );
michael@0:                 sum_Q6 = silk_SMLAWB( sum_Q6, CNG_sig_Q10[ MAX_LPC_ORDER + i - 16 ], A_Q12[ 15 ] );
michael@0:             }
michael@0: 
michael@0:             /* Update states */
michael@0:             CNG_sig_Q10[ MAX_LPC_ORDER + i ] = silk_ADD_LSHIFT( CNG_sig_Q10[ MAX_LPC_ORDER + i ], sum_Q6, 4 );
michael@0: 
michael@0:             frame[ i ] = silk_ADD_SAT16( frame[ i ], silk_RSHIFT_ROUND( sum_Q6, 6 ) );
michael@0:         }
michael@0:         silk_memcpy( psCNG->CNG_synth_state, &CNG_sig_Q10[ length ], MAX_LPC_ORDER * sizeof( opus_int32 ) );
michael@0:     } else {
michael@0:         silk_memset( psCNG->CNG_synth_state, 0, psDec->LPC_order *  sizeof( opus_int32 ) );
michael@0:     }
michael@0:     RESTORE_STACK;
michael@0: }