ref: 2955f68b14a1a8b8fb2be4af170ed621b8f73c9d
dir: /silk/NLSF_decode.c/
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#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include "main.h"
/* Predictive dequantizer for NLSF residuals */
static OPUS_INLINE void silk_NLSF_residual_dequant( /* O Returns RD value in Q30 */
opus_int16 x_Q10[], /* O Output [ order ] */
const opus_int8 indices[], /* I Quantization indices [ order ] */
const opus_uint8 pred_coef_Q8[], /* I Backward predictor coefs [ order ] */
const opus_int quant_step_size_Q16, /* I Quantization step size */
const opus_int16 order /* I Number of input values */
)
{
opus_int i, out_Q10, pred_Q10;
out_Q10 = 0;
for( i = order-1; i >= 0; i-- ) {
pred_Q10 = silk_RSHIFT( silk_SMULBB( out_Q10, (opus_int16)pred_coef_Q8[ i ] ), 8 );
out_Q10 = silk_LSHIFT( indices[ i ], 10 );
if( out_Q10 > 0 ) {
out_Q10 = silk_SUB16( out_Q10, SILK_FIX_CONST( NLSF_QUANT_LEVEL_ADJ, 10 ) );
} else if( out_Q10 < 0 ) {
out_Q10 = silk_ADD16( out_Q10, SILK_FIX_CONST( NLSF_QUANT_LEVEL_ADJ, 10 ) );
}
out_Q10 = silk_SMLAWB( pred_Q10, (opus_int32)out_Q10, quant_step_size_Q16 );
x_Q10[ i ] = out_Q10;
}
}
/***********************/
/* NLSF vector decoder */
/***********************/
opus_int silk_NLSF_decode( /* O Number of bits (Q5), if signalType >= 0 */
opus_int16 *pNLSF_Q15, /* O Quantized NLSF vector [ LPC_ORDER ] */
opus_int8 *NLSFIndices, /* I Codebook path vector [ LPC_ORDER + 1 ] */
const silk_NLSF_CB_struct *psNLSF_CB, /* I Codebook object */
const opus_int signalType /* I SignalType, to determine number of bits */
)
{
opus_int i;
opus_uint8 pred_Q8[ MAX_LPC_ORDER ];
opus_int16 ec_ix[ MAX_LPC_ORDER ];
opus_int16 res_Q10[ MAX_LPC_ORDER ];
opus_int32 NLSF_Q15_tmp;
const opus_uint8 *pCB_element;
const opus_int16 *pCB_Wght_Q9;
/* Unpack entropy table indices and predictor for current CB1 index */
silk_NLSF_unpack( ec_ix, pred_Q8, psNLSF_CB, NLSFIndices[ 0 ] );
/* Predictive residual dequantizer */
silk_NLSF_residual_dequant( res_Q10, &NLSFIndices[ 1 ], pred_Q8, psNLSF_CB->quantStepSize_Q16, psNLSF_CB->order );
/* Apply inverse square-rooted weights to first stage and add to output */
pCB_element = &psNLSF_CB->CB1_NLSF_Q8[ NLSFIndices[ 0 ] * psNLSF_CB->order ];
pCB_Wght_Q9 = &psNLSF_CB->CB1_Wght_Q9[ NLSFIndices[ 0 ] * psNLSF_CB->order ];
for( i = 0; i < psNLSF_CB->order; i++ ) {
NLSF_Q15_tmp = silk_ADD_LSHIFT32( silk_DIV32_16( silk_LSHIFT( (opus_int32)res_Q10[ i ], 14 ), pCB_Wght_Q9[ i ] ), (opus_int16)pCB_element[ i ], 7 );
pNLSF_Q15[ i ] = (opus_int16)silk_LIMIT( NLSF_Q15_tmp, 0, 32767 );
}
/* NLSF stabilization */
silk_NLSF_stabilize( pNLSF_Q15, psNLSF_CB->deltaMin_Q15, psNLSF_CB->order );
if( signalType >= 0 ) {
opus_int prob_Q8, bits_Q5;
const opus_uint8 *iCDF_ptr;
bits_Q5 = 0;
iCDF_ptr = &psNLSF_CB->CB1_iCDF[ ( signalType >> 1 ) * psNLSF_CB->nVectors ];
if( NLSFIndices[ 0 ] == 0 ) {
prob_Q8 = 256 - iCDF_ptr[ NLSFIndices[ 0 ] ];
} else {
prob_Q8 = iCDF_ptr[ NLSFIndices[ 0 ] - 1 ] - iCDF_ptr[ NLSFIndices[ 0 ] ];
}
bits_Q5 = ( 8 << 5 ) - ( silk_lin2log( prob_Q8 ) >> 2 );
for( i = 0; i < psNLSF_CB->order; i++ ) {
const opus_uint8 *rates_Q5;
rates_Q5 = &psNLSF_CB->ec_Rates_Q5[ ec_ix[ i ] ];
bits_Q5 += rates_Q5[ NLSFIndices[ i + 1 ] + NLSF_QUANT_MAX_AMPLITUDE ];
}
return bits_Q5;
}
return 0;
}