gecko/media/libopus/silk/decode_indices.c

/***********************************************************************
Copyright (c) 2006-2012 IETF Trust and Skype Limited. All rights reserved.

This file is extracted from RFC6716. Please see that RFC for additional
information.

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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
IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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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 ] );
    silk_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 countour 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 );
}