ref: c77b96333b471c7b8a89852ee941e6a8987751b4
dir: /silk/SKP_Silk_decode_core.c/
/***********************************************************************
Copyright (c) 2006-2011, Skype Limited. All rights reserved.
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modification, (subject to the limitations in the disclaimer below)
are permitted provided that the following conditions are met:
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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.
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this software without specific prior written permission.
NO EXPRESS OR IMPLIED LICENSES TO ANY PARTY'S PATENT RIGHTS ARE GRANTED
BY THIS LICENSE. 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
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OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
***********************************************************************/
#include "SKP_Silk_main.h"
/**********************************************************/
/* Core decoder. Performs inverse NSQ operation LTP + LPC */
/**********************************************************/
void SKP_Silk_decode_core(
SKP_Silk_decoder_state *psDec, /* I/O Decoder state */
SKP_Silk_decoder_control *psDecCtrl, /* I Decoder control */
SKP_int16 xq[], /* O Decoded speech */
const SKP_int pulses[ MAX_FRAME_LENGTH ] /* I Pulse signal */
)
{
SKP_int i, j, k, lag = 0, start_idx, sLTP_buf_idx, NLSF_interpolation_flag, signalType;
SKP_int16 *A_Q12, *B_Q14, *pxq, A_Q12_tmp[ MAX_LPC_ORDER ];
SKP_int16 sLTP[ MAX_FRAME_LENGTH ];
SKP_int32 LTP_pred_Q14, LPC_pred_Q10, Gain_Q16, inv_gain_Q16, inv_gain_Q32, gain_adj_Q16, rand_seed, offset_Q10;
SKP_int32 *pred_lag_ptr, *pexc_Q10, *pres_Q10;
SKP_int32 res_Q10[ MAX_SUB_FRAME_LENGTH ];
SKP_int32 vec_Q10[ MAX_SUB_FRAME_LENGTH ];
SKP_assert( psDec->prev_inv_gain_Q16 != 0 );
offset_Q10 = SKP_Silk_Quantization_Offsets_Q10[ psDec->indices.signalType >> 1 ][ psDec->indices.quantOffsetType ];
if( psDec->indices.NLSFInterpCoef_Q2 < 1 << 2 ) {
NLSF_interpolation_flag = 1;
} else {
NLSF_interpolation_flag = 0;
}
/* Decode excitation */
rand_seed = psDec->indices.Seed;
for( i = 0; i < psDec->frame_length; i++ ) {
rand_seed = SKP_RAND( rand_seed );
psDec->exc_Q10[ i ] = SKP_LSHIFT( ( SKP_int32 )pulses[ i ], 10 );
if( psDec->exc_Q10[ i ] > 0 ) {
psDec->exc_Q10[ i ] -= QUANT_LEVEL_ADJUST_Q10;
} else
if( psDec->exc_Q10[ i ] < 0 ) {
psDec->exc_Q10[ i ] += QUANT_LEVEL_ADJUST_Q10;
}
psDec->exc_Q10[ i ] += offset_Q10;
psDec->exc_Q10[ i ] ^= SKP_RSHIFT( rand_seed, 31 );
rand_seed += pulses[ i ];
}
#ifdef SAVE_ALL_INTERNAL_DATA
DEBUG_STORE_DATA( dec_q.dat, pulses, psDec->frame_length * sizeof( SKP_int ) );
#endif
pexc_Q10 = psDec->exc_Q10;
pxq = &psDec->outBuf[ psDec->ltp_mem_length ];
sLTP_buf_idx = psDec->ltp_mem_length;
/* Loop over subframes */
for( k = 0; k < psDec->nb_subfr; k++ ) {
pres_Q10 = res_Q10;
A_Q12 = psDecCtrl->PredCoef_Q12[ k >> 1 ];
/* Preload LPC coeficients to array on stack. Gives small performance gain */
SKP_memcpy( A_Q12_tmp, A_Q12, psDec->LPC_order * sizeof( SKP_int16 ) );
B_Q14 = &psDecCtrl->LTPCoef_Q14[ k * LTP_ORDER ];
Gain_Q16 = psDecCtrl->Gains_Q16[ k ];
signalType = psDec->indices.signalType;
inv_gain_Q16 = SKP_INVERSE32_varQ( SKP_max( Gain_Q16, 1 ), 32 );
inv_gain_Q16 = SKP_min( inv_gain_Q16, SKP_int16_MAX );
/* Calculate Gain adjustment factor */
gain_adj_Q16 = 1 << 16;
if( inv_gain_Q16 != psDec->prev_inv_gain_Q16 ) {
gain_adj_Q16 = SKP_DIV32_varQ( inv_gain_Q16, psDec->prev_inv_gain_Q16, 16 );
/* Scale short term state */
for( i = 0; i < MAX_LPC_ORDER; i++ ) {
psDec->sLPC_Q14[ i ] = SKP_SMULWW( gain_adj_Q16, psDec->sLPC_Q14[ i ] );
}
}
/* Save inv_gain */
SKP_assert( inv_gain_Q16 != 0 );
psDec->prev_inv_gain_Q16 = inv_gain_Q16;
/* Avoid abrupt transition from voiced PLC to unvoiced normal decoding */
if( psDec->lossCnt && psDec->prevSignalType == TYPE_VOICED &&
psDec->indices.signalType != TYPE_VOICED && k < MAX_NB_SUBFR/2 ) {
SKP_memset( B_Q14, 0, LTP_ORDER * sizeof( SKP_int16 ) );
B_Q14[ LTP_ORDER/2 ] = SKP_FIX_CONST( 0.25, 14 );
signalType = TYPE_VOICED;
psDecCtrl->pitchL[ k ] = psDec->lagPrev;
}
if( signalType == TYPE_VOICED ) {
/* Voiced */
lag = psDecCtrl->pitchL[ k ];
/* Re-whitening */
if( ( k & ( 3 - SKP_LSHIFT( NLSF_interpolation_flag, 1 ) ) ) == 0 ) {
/* Rewhiten with new A coefs */
start_idx = psDec->ltp_mem_length - lag - psDec->LPC_order - LTP_ORDER / 2;
SKP_assert( start_idx > 0 );
SKP_Silk_LPC_analysis_filter( &sLTP[ start_idx ], &psDec->outBuf[ start_idx + k * psDec->subfr_length ],
A_Q12, psDec->ltp_mem_length - start_idx, psDec->LPC_order );
/* After rewhitening the LTP state is unscaled */
inv_gain_Q32 = SKP_LSHIFT( inv_gain_Q16, 16 );
if( k == 0 ) {
/* Do LTP downscaling */
inv_gain_Q32 = SKP_LSHIFT( SKP_SMULWB( inv_gain_Q32, psDecCtrl->LTP_scale_Q14 ), 2 );
}
for( i = 0; i < lag + LTP_ORDER/2; i++ ) {
psDec->sLTP_Q16[ sLTP_buf_idx - i - 1 ] = SKP_SMULWB( inv_gain_Q32, sLTP[ psDec->ltp_mem_length - i - 1 ] );
}
} else {
/* Update LTP state when Gain changes */
if( gain_adj_Q16 != 1 << 16 ) {
for( i = 0; i < lag + LTP_ORDER/2; i++ ) {
psDec->sLTP_Q16[ sLTP_buf_idx - i - 1 ] = SKP_SMULWW( gain_adj_Q16, psDec->sLTP_Q16[ sLTP_buf_idx - i - 1 ] );
}
}
}
}
/* Long-term prediction */
if( signalType == TYPE_VOICED ) {
/* Setup pointer */
pred_lag_ptr = &psDec->sLTP_Q16[ sLTP_buf_idx - lag + LTP_ORDER / 2 ];
for( i = 0; i < psDec->subfr_length; i++ ) {
/* Unrolled loop */
LTP_pred_Q14 = SKP_SMULWB( pred_lag_ptr[ 0 ], B_Q14[ 0 ] );
LTP_pred_Q14 = SKP_SMLAWB( LTP_pred_Q14, pred_lag_ptr[ -1 ], B_Q14[ 1 ] );
LTP_pred_Q14 = SKP_SMLAWB( LTP_pred_Q14, pred_lag_ptr[ -2 ], B_Q14[ 2 ] );
LTP_pred_Q14 = SKP_SMLAWB( LTP_pred_Q14, pred_lag_ptr[ -3 ], B_Q14[ 3 ] );
LTP_pred_Q14 = SKP_SMLAWB( LTP_pred_Q14, pred_lag_ptr[ -4 ], B_Q14[ 4 ] );
pred_lag_ptr++;
/* Generate LPC excitation */
pres_Q10[ i ] = SKP_ADD32( pexc_Q10[ i ], SKP_RSHIFT_ROUND( LTP_pred_Q14, 4 ) );
/* Update states */
psDec->sLTP_Q16[ sLTP_buf_idx ] = SKP_LSHIFT( pres_Q10[ i ], 6 );
sLTP_buf_idx++;
}
} else {
pres_Q10 = pexc_Q10;
}
#ifdef SAVE_ALL_INTERNAL_DATA
DEBUG_STORE_DATA( dec_exc_Q10.dat, pexc_Q10, psDec->subfr_length * sizeof( SKP_int32 ) );
DEBUG_STORE_DATA( dec_res_Q10.dat, pres_Q10, psDec->subfr_length * sizeof( SKP_int32 ) );
#endif
for( i = 0; i < psDec->subfr_length; i++ ) {
/* Partially unrolled */
LPC_pred_Q10 = SKP_SMULWB( psDec->sLPC_Q14[ MAX_LPC_ORDER + i - 1 ], A_Q12_tmp[ 0 ] );
LPC_pred_Q10 = SKP_SMLAWB( LPC_pred_Q10, psDec->sLPC_Q14[ MAX_LPC_ORDER + i - 2 ], A_Q12_tmp[ 1 ] );
LPC_pred_Q10 = SKP_SMLAWB( LPC_pred_Q10, psDec->sLPC_Q14[ MAX_LPC_ORDER + i - 3 ], A_Q12_tmp[ 2 ] );
LPC_pred_Q10 = SKP_SMLAWB( LPC_pred_Q10, psDec->sLPC_Q14[ MAX_LPC_ORDER + i - 4 ], A_Q12_tmp[ 3 ] );
LPC_pred_Q10 = SKP_SMLAWB( LPC_pred_Q10, psDec->sLPC_Q14[ MAX_LPC_ORDER + i - 5 ], A_Q12_tmp[ 4 ] );
LPC_pred_Q10 = SKP_SMLAWB( LPC_pred_Q10, psDec->sLPC_Q14[ MAX_LPC_ORDER + i - 6 ], A_Q12_tmp[ 5 ] );
LPC_pred_Q10 = SKP_SMLAWB( LPC_pred_Q10, psDec->sLPC_Q14[ MAX_LPC_ORDER + i - 7 ], A_Q12_tmp[ 6 ] );
LPC_pred_Q10 = SKP_SMLAWB( LPC_pred_Q10, psDec->sLPC_Q14[ MAX_LPC_ORDER + i - 8 ], A_Q12_tmp[ 7 ] );
LPC_pred_Q10 = SKP_SMLAWB( LPC_pred_Q10, psDec->sLPC_Q14[ MAX_LPC_ORDER + i - 9 ], A_Q12_tmp[ 8 ] );
LPC_pred_Q10 = SKP_SMLAWB( LPC_pred_Q10, psDec->sLPC_Q14[ MAX_LPC_ORDER + i - 10 ], A_Q12_tmp[ 9 ] );
for( j = 10; j < psDec->LPC_order; j++ ) {
LPC_pred_Q10 = SKP_SMLAWB( LPC_pred_Q10, psDec->sLPC_Q14[ MAX_LPC_ORDER + i - j - 1 ], A_Q12_tmp[ j ] );
}
/* Add prediction to LPC excitation */
vec_Q10[ i ] = SKP_ADD32( pres_Q10[ i ], LPC_pred_Q10 );
/* Update states */
psDec->sLPC_Q14[ MAX_LPC_ORDER + i ] = SKP_LSHIFT( vec_Q10[ i ], 4 );
}
/* Scale with Gain */
for( i = 0; i < psDec->subfr_length; i++ ) {
pxq[ i ] = ( SKP_int16 )SKP_SAT16( SKP_RSHIFT_ROUND( SKP_SMULWW( vec_Q10[ i ], Gain_Q16 ), 10 ) );
}
/* Update LPC filter state */
SKP_memcpy( psDec->sLPC_Q14, &psDec->sLPC_Q14[ psDec->subfr_length ], MAX_LPC_ORDER * sizeof( SKP_int32 ) );
pexc_Q10 += psDec->subfr_length;
pxq += psDec->subfr_length;
}
/* Copy to output */
SKP_memcpy( xq, &psDec->outBuf[ psDec->ltp_mem_length ], psDec->frame_length * sizeof( SKP_int16 ) );
#ifdef SAVE_ALL_INTERNAL_DATA
DEBUG_STORE_DATA( dec_sLTP_Q16.dat, &psDec->sLTP_Q16[ psDec->ltp_mem_length ], psDec->frame_length * sizeof( SKP_int32 ));
DEBUG_STORE_DATA( dec_xq.dat, xq, psDec->frame_length * sizeof( SKP_int16 ) );
#endif
}