/* Decodes signs of excitation */
void SKP_Silk_decode_signs(SKP_Silk_range_coder_state * sRC, /* I/O Range coder state */
int q[], /* I/O pulse signal */
const int length, /* I length of output */
const int sigtype, /* I Signal type */
const int QuantOffsetType, /* I Quantization offset type */
const int RateLevelIndex /* I Rate Level Index */
)
{
int i;
int data;
const uint16_t *cdf;
i = SKP_SMULBB(N_RATE_LEVELS - 1,
SKP_LSHIFT(sigtype,
1) + QuantOffsetType) + RateLevelIndex;
cdf = SKP_Silk_sign_CDF[i];
for (i = 0; i < length; i++) {
if (q[i] > 0) {
SKP_Silk_range_decoder(&data, sRC, cdf, 1);
/* attach sign */
/* implementation with shift, subtraction, multiplication */
q[i] *= SKP_dec_map(data);
}
}
}
/* Range decoder for multiple symbols */
void SKP_Silk_range_decoder_multi(
SKP_int data[], /* O uncompressed data [nSymbols] */
SKP_Silk_range_coder_state *psRC, /* I/O compressor data structure */
const SKP_uint16 * const prob[], /* I cumulative density functions */
const SKP_int probStartIx[], /* I initial (middle) entries of cdfs [nSymbols] */
const SKP_int nSymbols /* I number of data symbols */
)
{
SKP_int k;
for( k = 0; k < nSymbols; k++ ) {
SKP_Silk_range_decoder( &data[ k ], psRC, prob[ k ], probStartIx[ k ] );
}
}
static inline void decode_split(int *p_child1, /* O: pulse amplitude of first child subframe */
int *p_child2, /* O: pulse amplitude of second child subframe */
SKP_Silk_range_coder_state * sRC, /* I/O: compressor data structure */
const int p, /* I: pulse amplitude of current subframe */
const uint16_t * shell_table /* I: table of shell cdfs */
)
{
int cdf_middle;
const uint16_t *cdf;
if (p > 0) {
cdf_middle = SKP_RSHIFT(p, 1);
cdf = &shell_table[SKP_Silk_shell_code_table_offsets[p]];
SKP_Silk_range_decoder(p_child1, sRC, cdf, cdf_middle);
p_child2[0] = p - p_child1[0];
} else {
p_child1[0] = 0;
p_child2[0] = 0;
}
}
void SKP_Silk_decode_pulses(
SKP_Silk_range_coder_state *psRC, /* I/O Range coder state */
SKP_Silk_decoder_control *psDecCtrl, /* I/O Decoder control */
SKP_int q[], /* O Excitation signal */
const SKP_int frame_length /* I Frame length (preliminary) */
)
{
SKP_int i, j, k, iter, abs_q, nLS, bit;
SKP_int sum_pulses[ MAX_NB_SHELL_BLOCKS ], nLshifts[ MAX_NB_SHELL_BLOCKS ];
SKP_int *pulses_ptr;
const SKP_uint16 *cdf_ptr;
/*********************/
/* Decode rate level */
/*********************/
SKP_Silk_range_decoder( &psDecCtrl->RateLevelIndex, psRC,
SKP_Silk_rate_levels_CDF[ psDecCtrl->sigtype ], SKP_Silk_rate_levels_CDF_offset );
/* Calculate number of shell blocks */
iter = frame_length / SHELL_CODEC_FRAME_LENGTH;
/***************************************************/
/* Sum-Weighted-Pulses Decoding */
/***************************************************/
cdf_ptr = SKP_Silk_pulses_per_block_CDF[ psDecCtrl->RateLevelIndex ];
for( i = 0; i < iter; i++ ) {
nLshifts[ i ] = 0;
SKP_Silk_range_decoder( &sum_pulses[ i ], psRC, cdf_ptr, SKP_Silk_pulses_per_block_CDF_offset );
/* LSB indication */
while( sum_pulses[ i ] == ( MAX_PULSES + 1 ) ) {
nLshifts[ i ]++;
SKP_Silk_range_decoder( &sum_pulses[ i ], psRC,
SKP_Silk_pulses_per_block_CDF[ N_RATE_LEVELS - 1 ], SKP_Silk_pulses_per_block_CDF_offset );
}
}
/***************************************************/
/* Shell decoding */
/***************************************************/
for( i = 0; i < iter; i++ ) {
if( sum_pulses[ i ] > 0 ) {
SKP_Silk_shell_decoder( &q[ SKP_SMULBB( i, SHELL_CODEC_FRAME_LENGTH ) ], psRC, sum_pulses[ i ] );
} else {
SKP_memset( &q[ SKP_SMULBB( i, SHELL_CODEC_FRAME_LENGTH ) ], 0, SHELL_CODEC_FRAME_LENGTH * sizeof( SKP_int ) );
}
}
/***************************************************/
/* LSB Decoding */
/***************************************************/
for( i = 0; i < iter; i++ ) {
if( nLshifts[ i ] > 0 ) {
nLS = nLshifts[ i ];
pulses_ptr = &q[ SKP_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 = SKP_LSHIFT( abs_q, 1 );
SKP_Silk_range_decoder( &bit, psRC, SKP_Silk_lsb_CDF, 1 );
abs_q += bit;
}
pulses_ptr[ k ] = abs_q;
}
}
}
/****************************************/
/* Decode and add signs to pulse signal */
/****************************************/
SKP_Silk_decode_signs( psRC, q, frame_length, psDecCtrl->sigtype,
psDecCtrl->QuantOffsetType, psDecCtrl->RateLevelIndex);
}
