godot/drivers/opus/silk/NLSF_encode.c

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#ifdef OPUS_ENABLED
#include "opus/opus_config.h"
#endif

#include "opus/silk/silk_main.h"
#include "opus/celt/stack_alloc.h"

/***********************/
/* NLSF vector encoder */
/***********************/
opus_int32 silk_NLSF_encode(                                    /* O    Returns RD value in Q25                     */
          opus_int8             *NLSFIndices,                   /* I    Codebook path vector [ LPC_ORDER + 1 ]      */
          opus_int16            *pNLSF_Q15,                     /* I/O  Quantized NLSF vector [ LPC_ORDER ]         */
    const silk_NLSF_CB_struct   *psNLSF_CB,                     /* I    Codebook object                             */
    const opus_int16            *pW_QW,                         /* I    NLSF weight vector [ LPC_ORDER ]            */
    const opus_int              NLSF_mu_Q20,                    /* I    Rate weight for the RD optimization         */
    const opus_int              nSurvivors,                     /* I    Max survivors after first stage             */
    const opus_int              signalType                      /* I    Signal type: 0/1/2                          */
)
{
    opus_int         i, s, ind1, bestIndex, prob_Q8, bits_q7;
    opus_int32       W_tmp_Q9;
    VARDECL( opus_int32, err_Q26 );
    VARDECL( opus_int32, RD_Q25 );
    VARDECL( opus_int, tempIndices1 );
    VARDECL( opus_int8, tempIndices2 );
    opus_int16       res_Q15[      MAX_LPC_ORDER ];
    opus_int16       res_Q10[      MAX_LPC_ORDER ];
    opus_int16       NLSF_tmp_Q15[ MAX_LPC_ORDER ];
    opus_int16       W_tmp_QW[     MAX_LPC_ORDER ];
    opus_int16       W_adj_Q5[     MAX_LPC_ORDER ];
    opus_uint8       pred_Q8[      MAX_LPC_ORDER ];
    opus_int16       ec_ix[        MAX_LPC_ORDER ];
    const opus_uint8 *pCB_element, *iCDF_ptr;
    SAVE_STACK;

    silk_assert( nSurvivors <= NLSF_VQ_MAX_SURVIVORS );
    silk_assert( signalType >= 0 && signalType <= 2 );
    silk_assert( NLSF_mu_Q20 <= 32767 && NLSF_mu_Q20 >= 0 );

    /* NLSF stabilization */
    silk_NLSF_stabilize( pNLSF_Q15, psNLSF_CB->deltaMin_Q15, psNLSF_CB->order );

    /* First stage: VQ */
    ALLOC( err_Q26, psNLSF_CB->nVectors, opus_int32 );
    silk_NLSF_VQ( err_Q26, pNLSF_Q15, psNLSF_CB->CB1_NLSF_Q8, psNLSF_CB->nVectors, psNLSF_CB->order );

    /* Sort the quantization errors */
    ALLOC( tempIndices1, nSurvivors, opus_int );
    silk_insertion_sort_increasing( err_Q26, tempIndices1, psNLSF_CB->nVectors, nSurvivors );

    ALLOC( RD_Q25, nSurvivors, opus_int32 );
    ALLOC( tempIndices2, nSurvivors * MAX_LPC_ORDER, opus_int8 );

    /* Loop over survivors */
    for( s = 0; s < nSurvivors; s++ ) {
        ind1 = tempIndices1[ s ];

        /* Residual after first stage */
        pCB_element = &psNLSF_CB->CB1_NLSF_Q8[ ind1 * psNLSF_CB->order ];
        for( i = 0; i < psNLSF_CB->order; i++ ) {
            NLSF_tmp_Q15[ i ] = silk_LSHIFT16( (opus_int16)pCB_element[ i ], 7 );
            res_Q15[ i ] = pNLSF_Q15[ i ] - NLSF_tmp_Q15[ i ];
        }

        /* Weights from codebook vector */
        silk_NLSF_VQ_weights_laroia( W_tmp_QW, NLSF_tmp_Q15, psNLSF_CB->order );

        /* Apply square-rooted weights */
        for( i = 0; i < psNLSF_CB->order; i++ ) {
            W_tmp_Q9 = silk_SQRT_APPROX( silk_LSHIFT( (opus_int32)W_tmp_QW[ i ], 18 - NLSF_W_Q ) );
            res_Q10[ i ] = (opus_int16)silk_RSHIFT( silk_SMULBB( res_Q15[ i ], W_tmp_Q9 ), 14 );
        }

        /* Modify input weights accordingly */
        for( i = 0; i < psNLSF_CB->order; i++ ) {
            W_adj_Q5[ i ] = silk_DIV32_16( silk_LSHIFT( (opus_int32)pW_QW[ i ], 5 ), W_tmp_QW[ i ] );
        }

        /* Unpack entropy table indices and predictor for current CB1 index */
        silk_NLSF_unpack( ec_ix, pred_Q8, psNLSF_CB, ind1 );

        /* Trellis quantizer */
        RD_Q25[ s ] = silk_NLSF_del_dec_quant( &tempIndices2[ s * MAX_LPC_ORDER ], res_Q10, W_adj_Q5, pred_Q8, ec_ix,
            psNLSF_CB->ec_Rates_Q5, psNLSF_CB->quantStepSize_Q16, psNLSF_CB->invQuantStepSize_Q6, NLSF_mu_Q20, psNLSF_CB->order );

        /* Add rate for first stage */
        iCDF_ptr = &psNLSF_CB->CB1_iCDF[ ( signalType >> 1 ) * psNLSF_CB->nVectors ];
        if( ind1 == 0 ) {
            prob_Q8 = 256 - iCDF_ptr[ ind1 ];
        } else {
            prob_Q8 = iCDF_ptr[ ind1 - 1 ] - iCDF_ptr[ ind1 ];
        }
        bits_q7 = ( 8 << 7 ) - silk_lin2log( prob_Q8 );
        RD_Q25[ s ] = silk_SMLABB( RD_Q25[ s ], bits_q7, silk_RSHIFT( NLSF_mu_Q20, 2 ) );
    }

    /* Find the lowest rate-distortion error */
    silk_insertion_sort_increasing( RD_Q25, &bestIndex, nSurvivors, 1 );

    NLSFIndices[ 0 ] = (opus_int8)tempIndices1[ bestIndex ];
    silk_memcpy( &NLSFIndices[ 1 ], &tempIndices2[ bestIndex * MAX_LPC_ORDER ], psNLSF_CB->order * sizeof( opus_int8 ) );

    /* Decode */
    silk_NLSF_decode( pNLSF_Q15, NLSFIndices, psNLSF_CB );

    RESTORE_STACK;
    return RD_Q25[ 0 ];
}