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mumbledj/vendor/github.com/layeh/gopus/opus-1.1.2/silk/NLSF_decode.c
2016-06-20 17:50:40 -07:00

102 lines
4.9 KiB
C

/***********************************************************************
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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
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LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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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 */
/***********************/
void silk_NLSF_decode(
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 */
)
{
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_int16 W_tmp_QW[ MAX_LPC_ORDER ];
opus_int32 W_tmp_Q9, NLSF_Q15_tmp;
const opus_uint8 *pCB_element;
/* Decode first stage */
pCB_element = &psNLSF_CB->CB1_NLSF_Q8[ NLSFIndices[ 0 ] * psNLSF_CB->order ];
for( i = 0; i < psNLSF_CB->order; i++ ) {
pNLSF_Q15[ i ] = silk_LSHIFT( (opus_int16)pCB_element[ i ], 7 );
}
/* 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 );
/* Weights from codebook vector */
silk_NLSF_VQ_weights_laroia( W_tmp_QW, pNLSF_Q15, psNLSF_CB->order );
/* Apply inverse square-rooted weights and add to output */
for( i = 0; i < psNLSF_CB->order; i++ ) {
W_tmp_Q9 = silk_SQRT_APPROX( silk_LSHIFT( (opus_int32)W_tmp_QW[ i ], 18 - NLSF_W_Q ) );
NLSF_Q15_tmp = silk_ADD32( pNLSF_Q15[ i ], silk_DIV32_16( silk_LSHIFT( (opus_int32)res_Q10[ i ], 14 ), W_tmp_Q9 ) );
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 );
}