xref: /aosp_15_r20/external/libopus/silk/NLSF_unpack.c (revision a58d3d2adb790c104798cd88c8a3aff4fa8b82cc)
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26*a58d3d2aSXin Li ***********************************************************************/
27*a58d3d2aSXin Li 
28*a58d3d2aSXin Li #ifdef HAVE_CONFIG_H
29*a58d3d2aSXin Li #include "config.h"
30*a58d3d2aSXin Li #endif
31*a58d3d2aSXin Li 
32*a58d3d2aSXin Li #include "main.h"
33*a58d3d2aSXin Li 
34*a58d3d2aSXin Li /* Unpack predictor values and indices for entropy coding tables */
silk_NLSF_unpack(opus_int16 ec_ix[],opus_uint8 pred_Q8[],const silk_NLSF_CB_struct * psNLSF_CB,const opus_int CB1_index)35*a58d3d2aSXin Li void silk_NLSF_unpack(
36*a58d3d2aSXin Li           opus_int16            ec_ix[],                        /* O    Indices to entropy tables [ LPC_ORDER ]     */
37*a58d3d2aSXin Li           opus_uint8            pred_Q8[],                      /* O    LSF predictor [ LPC_ORDER ]                 */
38*a58d3d2aSXin Li     const silk_NLSF_CB_struct   *psNLSF_CB,                     /* I    Codebook object                             */
39*a58d3d2aSXin Li     const opus_int              CB1_index                       /* I    Index of vector in first LSF codebook       */
40*a58d3d2aSXin Li )
41*a58d3d2aSXin Li {
42*a58d3d2aSXin Li     opus_int   i;
43*a58d3d2aSXin Li     opus_uint8 entry;
44*a58d3d2aSXin Li     const opus_uint8 *ec_sel_ptr;
45*a58d3d2aSXin Li 
46*a58d3d2aSXin Li     ec_sel_ptr = &psNLSF_CB->ec_sel[ CB1_index * psNLSF_CB->order / 2 ];
47*a58d3d2aSXin Li     for( i = 0; i < psNLSF_CB->order; i += 2 ) {
48*a58d3d2aSXin Li         entry = *ec_sel_ptr++;
49*a58d3d2aSXin Li         ec_ix  [ i     ] = silk_SMULBB( silk_RSHIFT( entry, 1 ) & 7, 2 * NLSF_QUANT_MAX_AMPLITUDE + 1 );
50*a58d3d2aSXin Li         pred_Q8[ i     ] = psNLSF_CB->pred_Q8[ i + ( entry & 1 ) * ( psNLSF_CB->order - 1 ) ];
51*a58d3d2aSXin Li         ec_ix  [ i + 1 ] = silk_SMULBB( silk_RSHIFT( entry, 5 ) & 7, 2 * NLSF_QUANT_MAX_AMPLITUDE + 1 );
52*a58d3d2aSXin Li         pred_Q8[ i + 1 ] = psNLSF_CB->pred_Q8[ i + ( silk_RSHIFT( entry, 4 ) & 1 ) * ( psNLSF_CB->order - 1 ) + 1 ];
53*a58d3d2aSXin Li     }
54*a58d3d2aSXin Li }
55*a58d3d2aSXin Li 
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