ref: a4dccd3f659eb60b8b3caa8b04688246851454bf
dir: /silk/decode_pulses.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
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***********************************************************************/
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include "main.h"
/*********************************************/
/* Decode quantization indices of excitation */
/*********************************************/
void silk_decode_pulses(
ec_dec *psRangeDec, /* I/O Compressor data structure */
opus_int pulses[], /* O Excitation signal */
const opus_int signalType, /* I Sigtype */
const opus_int quantOffsetType, /* I quantOffsetType */
const opus_int frame_length /* I Frame length */
)
{
opus_int i, j, k, iter, abs_q, nLS, RateLevelIndex;
opus_int sum_pulses[ MAX_NB_SHELL_BLOCKS ], nLshifts[ MAX_NB_SHELL_BLOCKS ];
opus_int *pulses_ptr;
const opus_uint8 *cdf_ptr;
/*********************/
/* Decode rate level */
/*********************/
RateLevelIndex = ec_dec_icdf( psRangeDec, silk_rate_levels_iCDF[ signalType >> 1 ], 8 );
/* Calculate number of shell blocks */
silk_assert( 1 << LOG2_SHELL_CODEC_FRAME_LENGTH == SHELL_CODEC_FRAME_LENGTH );
iter = silk_RSHIFT( frame_length, LOG2_SHELL_CODEC_FRAME_LENGTH );
if( iter * SHELL_CODEC_FRAME_LENGTH < frame_length ) {
silk_assert( frame_length == 12 * 10 ); /* Make sure only happens for 10 ms @ 12 kHz */
iter++;
}
/***************************************************/
/* Sum-Weighted-Pulses Decoding */
/***************************************************/
cdf_ptr = silk_pulses_per_block_iCDF[ RateLevelIndex ];
for( i = 0; i < iter; i++ ) {
nLshifts[ i ] = 0;
sum_pulses[ i ] = ec_dec_icdf( psRangeDec, cdf_ptr, 8 );
/* LSB indication */
while( sum_pulses[ i ] == MAX_PULSES + 1 ) {
nLshifts[ i ]++;
/* When we've already got 10 LSBs, we shift the table to not allow (MAX_PULSES + 1) */
sum_pulses[ i ] = ec_dec_icdf( psRangeDec,
silk_pulses_per_block_iCDF[ N_RATE_LEVELS - 1] + ( nLshifts[ i ] == 10 ), 8 );
}
}
/***************************************************/
/* Shell decoding */
/***************************************************/
for( i = 0; i < iter; i++ ) {
if( sum_pulses[ i ] > 0 ) {
silk_shell_decoder( &pulses[ silk_SMULBB( i, SHELL_CODEC_FRAME_LENGTH ) ], psRangeDec, sum_pulses[ i ] );
} else {
silk_memset( &pulses[ silk_SMULBB( i, SHELL_CODEC_FRAME_LENGTH ) ], 0, SHELL_CODEC_FRAME_LENGTH * sizeof( opus_int ) );
}
}
/***************************************************/
/* LSB Decoding */
/***************************************************/
for( i = 0; i < iter; i++ ) {
if( nLshifts[ i ] > 0 ) {
nLS = nLshifts[ i ];
pulses_ptr = &pulses[ silk_SMULBB( i, SHELL_CODEC_FRAME_LENGTH ) ];
for( k = 0; k < SHELL_CODEC_FRAME_LENGTH; k++ ) {
abs_q = pulses_ptr[ k ];
for( j = 0; j < nLS; j++ ) {
abs_q = silk_LSHIFT( abs_q, 1 );
abs_q += ec_dec_icdf( psRangeDec, silk_lsb_iCDF, 8 );
}
pulses_ptr[ k ] = abs_q;
}
/* Mark the number of pulses non-zero for sign decoding. */
sum_pulses[ i ] |= nLS << 5;
}
}
/****************************************/
/* Decode and add signs to pulse signal */
/****************************************/
silk_decode_signs( psRangeDec, pulses, frame_length, signalType, quantOffsetType, sum_pulses );
}