godot/drivers/opus/silk/NLSF_unpack.c

53 lines
2.9 KiB
C

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#include "opus/opus_config.h"
#include "opus/silk/main.h"
/* Unpack predictor values and indices for entropy coding tables */
void silk_NLSF_unpack(
opus_int16 ec_ix[], /* O Indices to entropy tables [ LPC_ORDER ] */
opus_uint8 pred_Q8[], /* O LSF predictor [ LPC_ORDER ] */
const silk_NLSF_CB_struct *psNLSF_CB, /* I Codebook object */
const opus_int CB1_index /* I Index of vector in first LSF codebook */
)
{
opus_int i;
opus_uint8 entry;
const opus_uint8 *ec_sel_ptr;
ec_sel_ptr = &psNLSF_CB->ec_sel[ CB1_index * psNLSF_CB->order / 2 ];
for( i = 0; i < psNLSF_CB->order; i += 2 ) {
entry = *ec_sel_ptr++;
ec_ix [ i ] = silk_SMULBB( silk_RSHIFT( entry, 1 ) & 7, 2 * NLSF_QUANT_MAX_AMPLITUDE + 1 );
pred_Q8[ i ] = psNLSF_CB->pred_Q8[ i + ( entry & 1 ) * ( psNLSF_CB->order - 1 ) ];
ec_ix [ i + 1 ] = silk_SMULBB( silk_RSHIFT( entry, 5 ) & 7, 2 * NLSF_QUANT_MAX_AMPLITUDE + 1 );
pred_Q8[ i + 1 ] = psNLSF_CB->pred_Q8[ i + ( silk_RSHIFT( entry, 4 ) & 1 ) * ( psNLSF_CB->order - 1 ) + 1 ];
}
}