godot/drivers/opus/silk/float/find_pred_coefs_FLP.c

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

#include "opus/silk/float/main_FLP.h"

/* Find LPC and LTP coefficients */
void silk_find_pred_coefs_FLP(
    silk_encoder_state_FLP          *psEnc,                             /* I/O  Encoder state FLP                           */
    silk_encoder_control_FLP        *psEncCtrl,                         /* I/O  Encoder control FLP                         */
    const silk_float                res_pitch[],                        /* I    Residual from pitch analysis                */
    const silk_float                x[],                                /* I    Speech signal                               */
    opus_int                        condCoding                          /* I    The type of conditional coding to use       */
)
{
    opus_int         i;
    silk_float       WLTP[ MAX_NB_SUBFR * LTP_ORDER * LTP_ORDER ];
    silk_float       invGains[ MAX_NB_SUBFR ], Wght[ MAX_NB_SUBFR ];
    opus_int16       NLSF_Q15[ MAX_LPC_ORDER ];
    const silk_float *x_ptr;
    silk_float       *x_pre_ptr, LPC_in_pre[ MAX_NB_SUBFR * MAX_LPC_ORDER + MAX_FRAME_LENGTH ];
    silk_float       minInvGain;

    /* Weighting for weighted least squares */
    for( i = 0; i < psEnc->sCmn.nb_subfr; i++ ) {
        silk_assert( psEncCtrl->Gains[ i ] > 0.0f );
        invGains[ i ] = 1.0f / psEncCtrl->Gains[ i ];
        Wght[ i ]     = invGains[ i ] * invGains[ i ];
    }

    if( psEnc->sCmn.indices.signalType == TYPE_VOICED ) {
        /**********/
        /* VOICED */
        /**********/
        silk_assert( psEnc->sCmn.ltp_mem_length - psEnc->sCmn.predictLPCOrder >= psEncCtrl->pitchL[ 0 ] + LTP_ORDER / 2 );

        /* LTP analysis */
        silk_find_LTP_FLP( psEncCtrl->LTPCoef, WLTP, &psEncCtrl->LTPredCodGain, res_pitch,
            psEncCtrl->pitchL, Wght, psEnc->sCmn.subfr_length, psEnc->sCmn.nb_subfr, psEnc->sCmn.ltp_mem_length );

        /* Quantize LTP gain parameters */
        silk_quant_LTP_gains_FLP( psEncCtrl->LTPCoef, psEnc->sCmn.indices.LTPIndex, &psEnc->sCmn.indices.PERIndex,
            &psEnc->sCmn.sum_log_gain_Q7, WLTP, psEnc->sCmn.mu_LTP_Q9, psEnc->sCmn.LTPQuantLowComplexity, psEnc->sCmn.nb_subfr );

        /* Control LTP scaling */
        silk_LTP_scale_ctrl_FLP( psEnc, psEncCtrl, condCoding );

        /* Create LTP residual */
        silk_LTP_analysis_filter_FLP( LPC_in_pre, x - psEnc->sCmn.predictLPCOrder, psEncCtrl->LTPCoef,
            psEncCtrl->pitchL, invGains, psEnc->sCmn.subfr_length, psEnc->sCmn.nb_subfr, psEnc->sCmn.predictLPCOrder );
    } else {
        /************/
        /* UNVOICED */
        /************/
        /* Create signal with prepended subframes, scaled by inverse gains */
        x_ptr     = x - psEnc->sCmn.predictLPCOrder;
        x_pre_ptr = LPC_in_pre;
        for( i = 0; i < psEnc->sCmn.nb_subfr; i++ ) {
            silk_scale_copy_vector_FLP( x_pre_ptr, x_ptr, invGains[ i ],
                psEnc->sCmn.subfr_length + psEnc->sCmn.predictLPCOrder );
            x_pre_ptr += psEnc->sCmn.subfr_length + psEnc->sCmn.predictLPCOrder;
            x_ptr     += psEnc->sCmn.subfr_length;
        }
        silk_memset( psEncCtrl->LTPCoef, 0, psEnc->sCmn.nb_subfr * LTP_ORDER * sizeof( silk_float ) );
        psEncCtrl->LTPredCodGain = 0.0f;
		psEnc->sCmn.sum_log_gain_Q7 = 0;
    }

    /* Limit on total predictive coding gain */
    if( psEnc->sCmn.first_frame_after_reset ) {
        minInvGain = 1.0f / MAX_PREDICTION_POWER_GAIN_AFTER_RESET;
    } else {        
        minInvGain = (silk_float)pow( 2, psEncCtrl->LTPredCodGain / 3 ) /  MAX_PREDICTION_POWER_GAIN;
        minInvGain /= 0.25f + 0.75f * psEncCtrl->coding_quality;
    }

    /* LPC_in_pre contains the LTP-filtered input for voiced, and the unfiltered input for unvoiced */
    silk_find_LPC_FLP( &psEnc->sCmn, NLSF_Q15, LPC_in_pre, minInvGain );

    /* Quantize LSFs */
    silk_process_NLSFs_FLP( &psEnc->sCmn, psEncCtrl->PredCoef, NLSF_Q15, psEnc->sCmn.prev_NLSFq_Q15 );

    /* Calculate residual energy using quantized LPC coefficients */
    silk_residual_energy_FLP( psEncCtrl->ResNrg, LPC_in_pre, psEncCtrl->PredCoef, psEncCtrl->Gains,
        psEnc->sCmn.subfr_length, psEnc->sCmn.nb_subfr, psEnc->sCmn.predictLPCOrder );

    /* Copy to prediction struct for use in next frame for interpolation */
    silk_memcpy( psEnc->sCmn.prev_NLSFq_Q15, NLSF_Q15, sizeof( psEnc->sCmn.prev_NLSFq_Q15 ) );
}