opus/silk/quant_LTP_gains.c

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

#include "main.h"
#include "tuning_parameters.h"

void silk_quant_LTP_gains(
    opus_int16                  B_Q14[ MAX_NB_SUBFR * LTP_ORDER ],          /* O    Quantized LTP gains             */
    opus_int8                   cbk_index[ MAX_NB_SUBFR ],                  /* O    Codebook Index                  */
    opus_int8                   *periodicity_index,                         /* O    Periodicity Index               */
    opus_int32                  *sum_log_gain_Q7,                           /* I/O  Cumulative max prediction gain  */
    opus_int                    *pred_gain_dB_Q7,                           /* O    LTP prediction gain             */
    const opus_int32            XX_Q17[ MAX_NB_SUBFR*LTP_ORDER*LTP_ORDER ], /* I    Correlation matrix in Q18       */
    const opus_int32            xX_Q17[ MAX_NB_SUBFR*LTP_ORDER ],           /* I    Correlation vector in Q18       */
    const opus_int              subfr_len,                                  /* I    Number of samples per subframe  */
    const opus_int              nb_subfr,                                   /* I    Number of subframes             */
    int                         arch                                        /* I    Run-time architecture           */
)
{
    opus_int             j, k, cbk_size;
    opus_int8            temp_idx[ MAX_NB_SUBFR ];
    const opus_uint8     *cl_ptr_Q5;
    const opus_int8      *cbk_ptr_Q7;
    const opus_uint8     *cbk_gain_ptr_Q7;
    const opus_int32     *XX_Q17_ptr, *xX_Q17_ptr;
    opus_int32           res_nrg_Q15_subfr, res_nrg_Q15, rate_dist_Q7_subfr, rate_dist_Q7, min_rate_dist_Q7;
    opus_int32           sum_log_gain_tmp_Q7, best_sum_log_gain_Q7, max_gain_Q7;
    opus_int             gain_Q7;

    /***************************************************/
    /* iterate over different codebooks with different */
    /* rates/distortions, and choose best */
    /***************************************************/
    min_rate_dist_Q7 = silk_int32_MAX;
    best_sum_log_gain_Q7 = 0;
    for( k = 0; k < 3; k++ ) {
        /* Safety margin for pitch gain control, to take into account factors
           such as state rescaling/rewhitening. */
        opus_int32 gain_safety = SILK_FIX_CONST( 0.4, 7 );

        cl_ptr_Q5  = silk_LTP_gain_BITS_Q5_ptrs[ k ];
        cbk_ptr_Q7 = silk_LTP_vq_ptrs_Q7[        k ];
        cbk_gain_ptr_Q7 = silk_LTP_vq_gain_ptrs_Q7[ k ];
        cbk_size   = silk_LTP_vq_sizes[          k ];

        /* Set up pointers to first subframe */
        XX_Q17_ptr = XX_Q17;
        xX_Q17_ptr = xX_Q17;

        res_nrg_Q15 = 0;
        rate_dist_Q7 = 0;
        sum_log_gain_tmp_Q7 = *sum_log_gain_Q7;
        for( j = 0; j < nb_subfr; j++ ) {
            max_gain_Q7 = silk_log2lin( ( SILK_FIX_CONST( MAX_SUM_LOG_GAIN_DB / 6.0, 7 ) - sum_log_gain_tmp_Q7 )
                                        + SILK_FIX_CONST( 7, 7 ) ) - gain_safety;
            silk_VQ_WMat_EC(
                &temp_idx[ j ],         /* O    index of best codebook vector                           */
                &res_nrg_Q15_subfr,     /* O    residual energy                                         */
                &rate_dist_Q7_subfr,    /* O    best weighted quantization error + mu * rate            */
                &gain_Q7,               /* O    sum of absolute LTP coefficients                        */
                XX_Q17_ptr,             /* I    correlation matrix                                      */
                xX_Q17_ptr,             /* I    correlation vector                                      */
                cbk_ptr_Q7,             /* I    codebook                                                */
                cbk_gain_ptr_Q7,        /* I    codebook effective gains                                */
                cl_ptr_Q5,              /* I    code length for each codebook vector                    */
                subfr_len,              /* I    number of samples per subframe                          */
                max_gain_Q7,            /* I    maximum sum of absolute LTP coefficients                */
                cbk_size,               /* I    number of vectors in codebook                           */
                arch                    /* I    Run-time architecture                                   */
            );

            res_nrg_Q15  = silk_ADD_POS_SAT32( res_nrg_Q15, res_nrg_Q15_subfr );
            rate_dist_Q7 = silk_ADD_POS_SAT32( rate_dist_Q7, rate_dist_Q7_subfr );
            sum_log_gain_tmp_Q7 = silk_max(0, sum_log_gain_tmp_Q7
                                + silk_lin2log( gain_safety + gain_Q7 ) - SILK_FIX_CONST( 7, 7 ));

            XX_Q17_ptr += LTP_ORDER * LTP_ORDER;
            xX_Q17_ptr += LTP_ORDER;
        }

        if( rate_dist_Q7 <= min_rate_dist_Q7 ) {
            min_rate_dist_Q7 = rate_dist_Q7;
            *periodicity_index = (opus_int8)k;
            silk_memcpy( cbk_index, temp_idx, nb_subfr * sizeof( opus_int8 ) );
            best_sum_log_gain_Q7 = sum_log_gain_tmp_Q7;
        }
    }

    cbk_ptr_Q7 = silk_LTP_vq_ptrs_Q7[ *periodicity_index ];
    for( j = 0; j < nb_subfr; j++ ) {
        for( k = 0; k < LTP_ORDER; k++ ) {
            B_Q14[ j * LTP_ORDER + k ] = silk_LSHIFT( cbk_ptr_Q7[ cbk_index[ j ] * LTP_ORDER + k ], 7 );
        }
    }

    if( nb_subfr == 2 ) {
        res_nrg_Q15 = silk_RSHIFT32( res_nrg_Q15, 1 );
    } else {
        res_nrg_Q15 = silk_RSHIFT32( res_nrg_Q15, 2 );
    }

    *sum_log_gain_Q7 = best_sum_log_gain_Q7;
    *pred_gain_dB_Q7 = (opus_int)silk_SMULBB( -3, silk_lin2log( res_nrg_Q15 ) - ( 15 << 7 ) );
}