tor-browser

decode_indices.c (7245B)

---

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#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

#include "main.h"

/* Decode side-information parameters from payload */
void silk_decode_indices(
   silk_decoder_state          *psDec,                         /* I/O  State                                       */
   ec_dec                      *psRangeDec,                    /* I/O  Compressor data structure                   */
   opus_int                    FrameIndex,                     /* I    Frame number                                */
   opus_int                    decode_LBRR,                    /* I    Flag indicating LBRR data is being decoded  */
   opus_int                    condCoding                      /* I    The type of conditional coding to use       */
)
{
   opus_int   i, k, Ix;
   opus_int   decode_absolute_lagIndex, delta_lagIndex;
   opus_int16 ec_ix[ MAX_LPC_ORDER ];
   opus_uint8 pred_Q8[ MAX_LPC_ORDER ];

   /*******************************************/
   /* Decode signal type and quantizer offset */
   /*******************************************/
   if( decode_LBRR || psDec->VAD_flags[ FrameIndex ] ) {
       Ix = ec_dec_icdf( psRangeDec, silk_type_offset_VAD_iCDF, 8 ) + 2;
   } else {
       Ix = ec_dec_icdf( psRangeDec, silk_type_offset_no_VAD_iCDF, 8 );
   }
   psDec->indices.signalType      = (opus_int8)silk_RSHIFT( Ix, 1 );
   psDec->indices.quantOffsetType = (opus_int8)( Ix & 1 );

   /****************/
   /* Decode gains */
   /****************/
   /* First subframe */
   if( condCoding == CODE_CONDITIONALLY ) {
       /* Conditional coding */
       psDec->indices.GainsIndices[ 0 ] = (opus_int8)ec_dec_icdf( psRangeDec, silk_delta_gain_iCDF, 8 );
   } else {
       /* Independent coding, in two stages: MSB bits followed by 3 LSBs */
       psDec->indices.GainsIndices[ 0 ]  = (opus_int8)silk_LSHIFT( ec_dec_icdf( psRangeDec, silk_gain_iCDF[ psDec->indices.signalType ], 8 ), 3 );
       psDec->indices.GainsIndices[ 0 ] += (opus_int8)ec_dec_icdf( psRangeDec, silk_uniform8_iCDF, 8 );
   }

   /* Remaining subframes */
   for( i = 1; i < psDec->nb_subfr; i++ ) {
       psDec->indices.GainsIndices[ i ] = (opus_int8)ec_dec_icdf( psRangeDec, silk_delta_gain_iCDF, 8 );
   }

   /**********************/
   /* Decode LSF Indices */
   /**********************/
   psDec->indices.NLSFIndices[ 0 ] = (opus_int8)ec_dec_icdf( psRangeDec, &psDec->psNLSF_CB->CB1_iCDF[ ( psDec->indices.signalType >> 1 ) * psDec->psNLSF_CB->nVectors ], 8 );
   silk_NLSF_unpack( ec_ix, pred_Q8, psDec->psNLSF_CB, psDec->indices.NLSFIndices[ 0 ] );
   celt_assert( psDec->psNLSF_CB->order == psDec->LPC_order );
   for( i = 0; i < psDec->psNLSF_CB->order; i++ ) {
       Ix = ec_dec_icdf( psRangeDec, &psDec->psNLSF_CB->ec_iCDF[ ec_ix[ i ] ], 8 );
       if( Ix == 0 ) {
           Ix -= ec_dec_icdf( psRangeDec, silk_NLSF_EXT_iCDF, 8 );
       } else if( Ix == 2 * NLSF_QUANT_MAX_AMPLITUDE ) {
           Ix += ec_dec_icdf( psRangeDec, silk_NLSF_EXT_iCDF, 8 );
       }
       psDec->indices.NLSFIndices[ i+1 ] = (opus_int8)( Ix - NLSF_QUANT_MAX_AMPLITUDE );
   }

   /* Decode LSF interpolation factor */
   if( psDec->nb_subfr == MAX_NB_SUBFR ) {
       psDec->indices.NLSFInterpCoef_Q2 = (opus_int8)ec_dec_icdf( psRangeDec, silk_NLSF_interpolation_factor_iCDF, 8 );
   } else {
       psDec->indices.NLSFInterpCoef_Q2 = 4;
   }

   if( psDec->indices.signalType == TYPE_VOICED )
   {
       /*********************/
       /* Decode pitch lags */
       /*********************/
       /* Get lag index */
       decode_absolute_lagIndex = 1;
       if( condCoding == CODE_CONDITIONALLY && psDec->ec_prevSignalType == TYPE_VOICED ) {
           /* Decode Delta index */
           delta_lagIndex = (opus_int16)ec_dec_icdf( psRangeDec, silk_pitch_delta_iCDF, 8 );
           if( delta_lagIndex > 0 ) {
               delta_lagIndex = delta_lagIndex - 9;
               psDec->indices.lagIndex = (opus_int16)( psDec->ec_prevLagIndex + delta_lagIndex );
               decode_absolute_lagIndex = 0;
           }
       }
       if( decode_absolute_lagIndex ) {
           /* Absolute decoding */
           psDec->indices.lagIndex  = (opus_int16)ec_dec_icdf( psRangeDec, silk_pitch_lag_iCDF, 8 ) * silk_RSHIFT( psDec->fs_kHz, 1 );
           psDec->indices.lagIndex += (opus_int16)ec_dec_icdf( psRangeDec, psDec->pitch_lag_low_bits_iCDF, 8 );
       }
       psDec->ec_prevLagIndex = psDec->indices.lagIndex;

       /* Get contour index */
       psDec->indices.contourIndex = (opus_int8)ec_dec_icdf( psRangeDec, psDec->pitch_contour_iCDF, 8 );

       /********************/
       /* Decode LTP gains */
       /********************/
       /* Decode PERIndex value */
       psDec->indices.PERIndex = (opus_int8)ec_dec_icdf( psRangeDec, silk_LTP_per_index_iCDF, 8 );

       for( k = 0; k < psDec->nb_subfr; k++ ) {
           psDec->indices.LTPIndex[ k ] = (opus_int8)ec_dec_icdf( psRangeDec, silk_LTP_gain_iCDF_ptrs[ psDec->indices.PERIndex ], 8 );
       }

       /**********************/
       /* Decode LTP scaling */
       /**********************/
       if( condCoding == CODE_INDEPENDENTLY ) {
           psDec->indices.LTP_scaleIndex = (opus_int8)ec_dec_icdf( psRangeDec, silk_LTPscale_iCDF, 8 );
       } else {
           psDec->indices.LTP_scaleIndex = 0;
       }
   }
   psDec->ec_prevSignalType = psDec->indices.signalType;

   /***************/
   /* Decode seed */
   /***************/
   psDec->indices.Seed = (opus_int8)ec_dec_icdf( psRangeDec, silk_uniform4_iCDF, 8 );
}