/***********************************************************************
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***********************************************************************/
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include "main.h"
#include "stack_alloc.h"
/**********************************************************/
/* Core decoder. Performs inverse NSQ operation LTP + LPC */
/**********************************************************/
void silk_decode_core(
silk_decoder_state *psDec, /* I/O Decoder state */
silk_decoder_control *psDecCtrl, /* I Decoder control */
opus_int16 xq[], /* O Decoded speech */
const opus_int16 pulses[ MAX_FRAME_LENGTH ], /* I Pulse signal */
int arch /* I Run-time architecture */
)
{
opus_int i, k, lag = 0, start_idx, sLTP_buf_idx, NLSF_interpolation_flag, signalType;
opus_int16 *A_Q12, *B_Q14, *pxq, A_Q12_tmp[ MAX_LPC_ORDER ];
VARDECL( opus_int16, sLTP );
VARDECL( opus_int32, sLTP_Q15 );
opus_int32 LTP_pred_Q13, LPC_pred_Q10, Gain_Q10, inv_gain_Q31, gain_adj_Q16, rand_seed, offset_Q10;
opus_int32 *pred_lag_ptr, *pexc_Q14, *pres_Q14;
VARDECL( opus_int32, res_Q14 );
VARDECL( opus_int32, sLPC_Q14 );
SAVE_STACK;
silk_assert( psDec->prev_gain_Q16 != 0 );
ALLOC( sLTP, psDec->ltp_mem_length, opus_int16 );
ALLOC( sLTP_Q15, psDec->ltp_mem_length + psDec->frame_length, opus_int32 );
ALLOC( res_Q14, psDec->subfr_length, opus_int32 );
ALLOC( sLPC_Q14, psDec->subfr_length + MAX_LPC_ORDER, opus_int32 );
offset_Q10 = 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 = silk_RAND( rand_seed );
psDec->exc_Q14[ i ] = silk_LSHIFT( (opus_int32)pulses[ i ], 14 );
if( psDec->exc_Q14[ i ] > 0 ) {
psDec->exc_Q14[ i ] -= QUANT_LEVEL_ADJUST_Q10 << 4;
} else
if( psDec->exc_Q14[ i ] < 0 ) {
psDec->exc_Q14[ i ] += QUANT_LEVEL_ADJUST_Q10 << 4;
}
psDec->exc_Q14[ i ] += offset_Q10 << 4;
if( rand_seed < 0 ) {
psDec->exc_Q14[ i ] = -psDec->exc_Q14[ i ];
}
rand_seed = silk_ADD32_ovflw( rand_seed, pulses[ i ] );
}
/* Copy LPC state */
silk_memcpy( sLPC_Q14, psDec->sLPC_Q14_buf, MAX_LPC_ORDER * sizeof( opus_int32 ) );
pexc_Q14 = psDec->exc_Q14;
pxq = xq;
sLTP_buf_idx = psDec->ltp_mem_length;
/* Loop over subframes */
for( k = 0; k < psDec->nb_subfr; k++ ) {
pres_Q14 = res_Q14;
A_Q12 = psDecCtrl->PredCoef_Q12[ k >> 1 ];
/* Preload LPC coeficients to array on stack. Gives small performance gain */
silk_memcpy( A_Q12_tmp, A_Q12, psDec->LPC_order * sizeof( opus_int16 ) );
B_Q14 = &psDecCtrl->LTPCoef_Q14[ k * LTP_ORDER ];
signalType = psDec->indices.signalType;
Gain_Q10 = silk_RSHIFT( psDecCtrl->Gains_Q16[ k ], 6 );
inv_gain_Q31 = silk_INVERSE32_varQ( psDecCtrl->Gains_Q16[ k ], 47 );
/* Calculate gain adjustment factor */
if( psDecCtrl->Gains_Q16[ k ] != psDec->prev_gain_Q16 ) {
gain_adj_Q16 = silk_DIV32_varQ( psDec->prev_gain_Q16, psDecCtrl->Gains_Q16[ k ], 16 );
/* Scale short term state */
for( i = 0; i < MAX_LPC_ORDER; i++ ) {
sLPC_Q14[ i ] = silk_SMULWW( gain_adj_Q16, sLPC_Q14[ i ] );
}
} else {
gain_adj_Q16 = (opus_int32)1 << 16;
}
/* Save inv_gain */
silk_assert( inv_gain_Q31 != 0 );
psDec->prev_gain_Q16 = psDecCtrl->Gains_Q16[ k ];
/* 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 ) {
silk_memset( B_Q14, 0, LTP_ORDER * sizeof( opus_int16 ) );
B_Q14[ LTP_ORDER/2 ] = SILK_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 == 0 || ( k == 2 && NLSF_interpolation_flag ) ) {
/* Rewhiten with new A coefs */
start_idx = psDec->ltp_mem_length - lag - psDec->LPC_order - LTP_ORDER / 2;
silk_assert( start_idx > 0 );
if( k == 2 ) {
silk_memcpy( &psDec->outBuf[ psDec->ltp_mem_length ], xq, 2 * psDec->subfr_length * sizeof( opus_int16 ) );
}
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, arch );
/* After rewhitening the LTP state is unscaled */
if( k == 0 ) {
/* Do LTP downscaling to reduce inter-packet dependency */
inv_gain_Q31 = silk_LSHIFT( silk_SMULWB( inv_gain_Q31, psDecCtrl->LTP_scale_Q14 ), 2 );
}
for( i = 0; i < lag + LTP_ORDER/2; i++ ) {
sLTP_Q15[ sLTP_buf_idx - i - 1 ] = silk_SMULWB( inv_gain_Q31, sLTP[ psDec->ltp_mem_length - i - 1 ] );
}
} else {
/* Update LTP state when Gain changes */
if( gain_adj_Q16 != (opus_int32)1 << 16 ) {
for( i = 0; i < lag + LTP_ORDER/2; i++ ) {
sLTP_Q15[ sLTP_buf_idx - i - 1 ] = silk_SMULWW( gain_adj_Q16, sLTP_Q15[ sLTP_buf_idx - i - 1 ] );
}
}
}
}
/* Long-term prediction */
if( signalType == TYPE_VOICED ) {
/* Set up pointer */
pred_lag_ptr = &sLTP_Q15[ 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_Q13 = 2;
LTP_pred_Q13 = silk_SMLAWB( LTP_pred_Q13, pred_lag_ptr[ 0 ], B_Q14[ 0 ] );
LTP_pred_Q13 = silk_SMLAWB( LTP_pred_Q13, pred_lag_ptr[ -1 ], B_Q14[ 1 ] );
LTP_pred_Q13 = silk_SMLAWB( LTP_pred_Q13, pred_lag_ptr[ -2 ], B_Q14[ 2 ] );
LTP_pred_Q13 = silk_SMLAWB( LTP_pred_Q13, pred_lag_ptr[ -3 ], B_Q14[ 3 ] );
LTP_pred_Q13 = silk_SMLAWB( LTP_pred_Q13, pred_lag_ptr[ -4 ], B_Q14[ 4 ] );
pred_lag_ptr++;
/* Generate LPC excitation */
pres_Q14[ i ] = silk_ADD_LSHIFT32( pexc_Q14[ i ], LTP_pred_Q13, 1 );
/* Update states */
sLTP_Q15[ sLTP_buf_idx ] = silk_LSHIFT( pres_Q14[ i ], 1 );
sLTP_buf_idx++;
}
} else {
pres_Q14 = pexc_Q14;
}
for( i = 0; i < psDec->subfr_length; i++ ) {
/* Short-term prediction */
silk_assert( psDec->LPC_order == 10 || psDec->LPC_order == 16 );
/* 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[ MAX_LPC_ORDER + i - 1 ], A_Q12_tmp[ 0 ] );
LPC_pred_Q10 = silk_SMLAWB( LPC_pred_Q10, sLPC_Q14[ MAX_LPC_ORDER + i - 2 ], A_Q12_tmp[ 1 ] );
LPC_pred_Q10 = silk_SMLAWB( LPC_pred_Q10, sLPC_Q14[ MAX_LPC_ORDER + i - 3 ], A_Q12_tmp[ 2 ] );
LPC_pred_Q10 = silk_SMLAWB( LPC_pred_Q10, sLPC_Q14[ MAX_LPC_ORDER + i - 4 ], A_Q12_tmp[ 3 ] );
LPC_pred_Q10 = silk_SMLAWB( LPC_pred_Q10, sLPC_Q14[ MAX_LPC_ORDER + i - 5 ], A_Q12_tmp[ 4 ] );
LPC_pred_Q10 = silk_SMLAWB( LPC_pred_Q10, sLPC_Q14[ MAX_LPC_ORDER + i - 6 ], A_Q12_tmp[ 5 ] );
LPC_pred_Q10 = silk_SMLAWB( LPC_pred_Q10, sLPC_Q14[ MAX_LPC_ORDER + i - 7 ], A_Q12_tmp[ 6 ] );
LPC_pred_Q10 = silk_SMLAWB( LPC_pred_Q10, sLPC_Q14[ MAX_LPC_ORDER + i - 8 ], A_Q12_tmp[ 7 ] );
LPC_pred_Q10 = silk_SMLAWB( LPC_pred_Q10, sLPC_Q14[ MAX_LPC_ORDER + i - 9 ], A_Q12_tmp[ 8 ] );
LPC_pred_Q10 = silk_SMLAWB( LPC_pred_Q10, sLPC_Q14[ MAX_LPC_ORDER + i - 10 ], A_Q12_tmp[ 9 ] );
if( psDec->LPC_order == 16 ) {
LPC_pred_Q10 = silk_SMLAWB( LPC_pred_Q10, sLPC_Q14[ MAX_LPC_ORDER + i - 11 ], A_Q12_tmp[ 10 ] );
LPC_pred_Q10 = silk_SMLAWB( LPC_pred_Q10, sLPC_Q14[ MAX_LPC_ORDER + i - 12 ], A_Q12_tmp[ 11 ] );
LPC_pred_Q10 = silk_SMLAWB( LPC_pred_Q10, sLPC_Q14[ MAX_LPC_ORDER + i - 13 ], A_Q12_tmp[ 12 ] );
LPC_pred_Q10 = silk_SMLAWB( LPC_pred_Q10, sLPC_Q14[ MAX_LPC_ORDER + i - 14 ], A_Q12_tmp[ 13 ] );
LPC_pred_Q10 = silk_SMLAWB( LPC_pred_Q10, sLPC_Q14[ MAX_LPC_ORDER + i - 15 ], A_Q12_tmp[ 14 ] );
LPC_pred_Q10 = silk_SMLAWB( LPC_pred_Q10, sLPC_Q14[ MAX_LPC_ORDER + i - 16 ], A_Q12_tmp[ 15 ] );
}
/* Add prediction to LPC excitation */
sLPC_Q14[ MAX_LPC_ORDER + i ] = silk_ADD_SAT32( pres_Q14[ i ], silk_LSHIFT_SAT32( LPC_pred_Q10, 4 ) );
/* Scale with gain */
pxq[ i ] = (opus_int16)silk_SAT16( silk_RSHIFT_ROUND( silk_SMULWW( sLPC_Q14[ MAX_LPC_ORDER + i ], Gain_Q10 ), 8 ) );
}
/* DEBUG_STORE_DATA( dec.pcm, pxq, psDec->subfr_length * sizeof( opus_int16 ) ) */
/* Update LPC filter state */
silk_memcpy( sLPC_Q14, &sLPC_Q14[ psDec->subfr_length ], MAX_LPC_ORDER * sizeof( opus_int32 ) );
pexc_Q14 += psDec->subfr_length;
pxq += psDec->subfr_length;
}
/* Save LPC state */
silk_memcpy( psDec->sLPC_Q14_buf, sLPC_Q14, MAX_LPC_ORDER * sizeof( opus_int32 ) );
RESTORE_STACK;
}