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***********************************************************************/

#include "SKP_Silk_main_FLP.h"
#include "SKP_Silk_tuning_parameters.h"

/* Compute gain to make warped filter coefficients have a zero mean log frequency response on a     */
/* non-warped frequency scale. (So that it can be implemented with a minimum-phase monic filter.)   */
SKP_INLINE SKP_float warped_gain( 
    const SKP_float     *coefs, 
    SKP_float           lambda, 
    SKP_int             order 
) {
    SKP_int   i;
    SKP_float gain;

    lambda = -lambda;
    gain = coefs[ order - 1 ];
    for( i = order - 2; i >= 0; i-- ) {
        gain = lambda * gain + coefs[ i ];
    }
    return (SKP_float)( 1.0f / ( 1.0f - lambda * gain ) );
}

/* Convert warped filter coefficients to monic pseudo-warped coefficients and limit maximum     */
/* amplitude of monic warped coefficients by using bandwidth expansion on the true coefficients */
SKP_INLINE void warped_true2monic_coefs( 
    SKP_float           *coefs_syn,
    SKP_float           *coefs_ana,
    SKP_float           lambda,
    SKP_float           limit,
    SKP_int             order
) {
    SKP_int   i, iter, ind = 0;
    SKP_float tmp, maxabs, chirp, gain_syn, gain_ana;

    /* Convert to monic coefficients */
    for( i = order - 1; i > 0; i-- ) {
        coefs_syn[ i - 1 ] -= lambda * coefs_syn[ i ];
        coefs_ana[ i - 1 ] -= lambda * coefs_ana[ i ];
    } 
    gain_syn = ( 1.0f - lambda * lambda ) / ( 1.0f + lambda * coefs_syn[ 0 ] );
    gain_ana = ( 1.0f - lambda * lambda ) / ( 1.0f + lambda * coefs_ana[ 0 ] );
    for( i = 0; i < order; i++ ) {
        coefs_syn[ i ] *= gain_syn;
        coefs_ana[ i ] *= gain_ana;
    }

    /* Limit */
    for( iter = 0; iter < 10; iter++ ) {
        /* Find maximum absolute value */
        maxabs = -1.0f;
        for( i = 0; i < order; i++ ) {
            tmp = SKP_max( SKP_abs_float( coefs_syn[ i ] ), SKP_abs_float( coefs_ana[ i ] ) );
            if( tmp > maxabs ) {
                maxabs = tmp;
                ind = i;
            }
        }
        if( maxabs <= limit ) {
            /* Coefficients are within range - done */
            return;
        }

        /* Convert back to true warped coefficients */
        for( i = 1; i < order; i++ ) {
            coefs_syn[ i - 1 ] += lambda * coefs_syn[ i ];
            coefs_ana[ i - 1 ] += lambda * coefs_ana[ i ];
        }
        gain_syn = 1.0f / gain_syn;
        gain_ana = 1.0f / gain_ana;
        for( i = 0; i < order; i++ ) {
            coefs_syn[ i ] *= gain_syn;
            coefs_ana[ i ] *= gain_ana;
        }

        /* Apply bandwidth expansion */
        chirp = 0.99f - ( 0.8f + 0.1f * iter ) * ( maxabs - limit ) / ( maxabs * ( ind + 1 ) );
        SKP_Silk_bwexpander_FLP( coefs_syn, order, chirp );
        SKP_Silk_bwexpander_FLP( coefs_ana, order, chirp );

        /* Convert to monic warped coefficients */
        for( i = order - 1; i > 0; i-- ) {
            coefs_syn[ i - 1 ] -= lambda * coefs_syn[ i ];
            coefs_ana[ i - 1 ] -= lambda * coefs_ana[ i ];
        }
        gain_syn = ( 1.0f - lambda * lambda ) / ( 1.0f + lambda * coefs_syn[ 0 ] );
        gain_ana = ( 1.0f - lambda * lambda ) / ( 1.0f + lambda * coefs_ana[ 0 ] );
        for( i = 0; i < order; i++ ) {
            coefs_syn[ i ] *= gain_syn;
            coefs_ana[ i ] *= gain_ana;
        }
    }
	SKP_assert( 0 );
}

/* Compute noise shaping coefficients and initial gain values */
void SKP_Silk_noise_shape_analysis_FLP(
    SKP_Silk_encoder_state_FLP      *psEnc,             /* I/O  Encoder state FLP                       */
    SKP_Silk_encoder_control_FLP    *psEncCtrl,         /* I/O  Encoder control FLP                     */
    const SKP_float                 *pitch_res,         /* I    LPC residual from pitch analysis        */
    const SKP_float                 *x                  /* I    Input signal [frame_length + la_shape]  */
)
{
    SKP_Silk_shape_state_FLP *psShapeSt = &psEnc->sShape;
    SKP_int     k, nSamples;
    SKP_float   SNR_adj_dB, HarmBoost, HarmShapeGain, Tilt;
    SKP_float   nrg, pre_nrg, log_energy, log_energy_prev, energy_variation;
    SKP_float   delta, BWExp1, BWExp2, gain_mult, gain_add, strength, b, warping;
    SKP_float   x_windowed[ SHAPE_LPC_WIN_MAX ];
    SKP_float   auto_corr[ MAX_SHAPE_LPC_ORDER + 1 ];
    const SKP_float *x_ptr, *pitch_res_ptr;

    /* Point to start of first LPC analysis block */
    x_ptr = x - psEnc->sCmn.la_shape;

    /****************/
    /* CONTROL SNR  */
    /****************/
    /* Reduce SNR_dB values if recent bitstream has exceeded TargetRate */
    psEncCtrl->current_SNR_dB = psEnc->SNR_dB - 0.05f * psEnc->BufferedInChannel_ms;

    /* Reduce SNR_dB if inband FEC used */
    if( psEnc->speech_activity > LBRR_SPEECH_ACTIVITY_THRES ) {
        psEncCtrl->current_SNR_dB -= psEnc->inBandFEC_SNR_comp;
    }

    /****************/
    /* GAIN CONTROL */
    /****************/
    /* Input quality is the average of the quality in the lowest two VAD bands */
    psEncCtrl->input_quality = 0.5f * ( psEncCtrl->input_quality_bands[ 0 ] + psEncCtrl->input_quality_bands[ 1 ] );

    /* Coding quality level, between 0.0 and 1.0 */
    psEncCtrl->coding_quality = SKP_sigmoid( 0.25f * ( psEncCtrl->current_SNR_dB - 18.0f ) );

    /* Reduce coding SNR during low speech activity */
    b = 1.0f - psEnc->speech_activity;
    SNR_adj_dB = psEncCtrl->current_SNR_dB - 
        BG_SNR_DECR_dB * psEncCtrl->coding_quality * ( 0.5f + 0.5f * psEncCtrl->input_quality ) * b * b;

    if( psEncCtrl->sCmn.sigtype == SIG_TYPE_VOICED ) {
        /* Reduce gains for periodic signals */
        SNR_adj_dB += HARM_SNR_INCR_dB * psEnc->LTPCorr;
    } else { 
        /* For unvoiced signals and low-quality input, adjust the quality slower than SNR_dB setting */
        SNR_adj_dB += ( -0.4f * psEncCtrl->current_SNR_dB + 6.0f ) * ( 1.0f - psEncCtrl->input_quality );
    }

    /*************************/
    /* SPARSENESS PROCESSING */
    /*************************/
    /* Set quantizer offset */
    if( psEncCtrl->sCmn.sigtype == SIG_TYPE_VOICED ) {
        /* Initally set to 0; may be overruled in process_gains(..) */
        psEncCtrl->sCmn.QuantOffsetType = 0;
        psEncCtrl->sparseness = 0.0f;
    } else {
        /* Sparseness measure, based on relative fluctuations of energy per 2 milliseconds */
        nSamples = 2 * psEnc->sCmn.fs_kHz;
        energy_variation = 0.0f;
        log_energy_prev  = 0.0f;
        pitch_res_ptr = pitch_res;
        for( k = 0; k < FRAME_LENGTH_MS / 2; k++ ) {
            nrg = ( SKP_float )nSamples + ( SKP_float )SKP_Silk_energy_FLP( pitch_res_ptr, nSamples );
            log_energy = SKP_Silk_log2( nrg );
            if( k > 0 ) {
                energy_variation += SKP_abs_float( log_energy - log_energy_prev );
            }
            log_energy_prev = log_energy;
            pitch_res_ptr += nSamples;
        }
        psEncCtrl->sparseness = SKP_sigmoid( 0.4f * ( energy_variation - 5.0f ) );

        /* Set quantization offset depending on sparseness measure */
        if( psEncCtrl->sparseness > SPARSENESS_THRESHOLD_QNT_OFFSET ) {
            psEncCtrl->sCmn.QuantOffsetType = 0;
        } else {
            psEncCtrl->sCmn.QuantOffsetType = 1;
        }
        
        /* Increase coding SNR for sparse signals */
        SNR_adj_dB += SPARSE_SNR_INCR_dB * ( psEncCtrl->sparseness - 0.5f );
    }

    /*******************************/
    /* Control bandwidth expansion */
    /*******************************/
    /* More BWE for signals with high prediction gain */
    strength = FIND_PITCH_WHITE_NOISE_FRACTION * psEncCtrl->predGain;           /* between 0.0 and 1.0 */
    BWExp1 = BWExp2 = BANDWIDTH_EXPANSION / ( 1.0f + strength * strength );
    delta  = LOW_RATE_BANDWIDTH_EXPANSION_DELTA * ( 1.0f - 0.75f * psEncCtrl->coding_quality );
    BWExp1 -= delta;
    BWExp2 += delta;
    /* BWExp1 will be applied after BWExp2, so make it relative */
    BWExp1 /= BWExp2;

    if( psEnc->sCmn.warping_Q16 > 0 ) {
        /* Slightly more warping in analysis will move quantization noise up in frequency, where it's better masked */
        warping = (SKP_float)psEnc->sCmn.warping_Q16 / 65536.0f + 0.01f * psEncCtrl->coding_quality;
    } else {
        warping = 0.0f;
    }

    /********************************************/
    /* Compute noise shaping AR coefs and gains */
    /********************************************/
    for( k = 0; k < NB_SUBFR; k++ ) {
        /* Apply window: sine slope followed by flat part followed by cosine slope */
        SKP_int shift, slope_part, flat_part;
        flat_part = psEnc->sCmn.fs_kHz * 5;
        slope_part = ( psEnc->sCmn.shapeWinLength - flat_part ) / 2;

        SKP_Silk_apply_sine_window_FLP( x_windowed, x_ptr, 1, slope_part );
        shift = slope_part;
        SKP_memcpy( x_windowed + shift, x_ptr + shift, flat_part * sizeof(SKP_float) );
        shift += flat_part;
        SKP_Silk_apply_sine_window_FLP( x_windowed + shift, x_ptr + shift, 2, slope_part );

        /* Update pointer: next LPC analysis block */
        x_ptr += psEnc->sCmn.subfr_length;

        if( psEnc->sCmn.warping_Q16 > 0 ) {
            /* Calculate warped auto correlation */
            SKP_Silk_warped_autocorrelation_FLP( auto_corr, x_windowed, warping, 
                psEnc->sCmn.shapeWinLength, psEnc->sCmn.shapingLPCOrder );
        } else {
            /* Calculate regular auto correlation */
            SKP_Silk_autocorrelation_FLP( auto_corr, x_windowed, psEnc->sCmn.shapeWinLength, psEnc->sCmn.shapingLPCOrder + 1 );
        }

        /* Add white noise, as a fraction of energy */
        auto_corr[ 0 ] += auto_corr[ 0 ] * SHAPE_WHITE_NOISE_FRACTION; 

        /* Convert correlations to prediction coefficients, and compute residual energy */
        nrg = SKP_Silk_levinsondurbin_FLP( &psEncCtrl->AR2[ k * MAX_SHAPE_LPC_ORDER ], auto_corr, psEnc->sCmn.shapingLPCOrder );
        psEncCtrl->Gains[ k ] = ( SKP_float )sqrt( nrg );

        if( psEnc->sCmn.warping_Q16 > 0 ) {
            /* Adjust gain for warping */
            psEncCtrl->Gains[ k ] *= warped_gain( &psEncCtrl->AR2[ k * MAX_SHAPE_LPC_ORDER ], warping, psEnc->sCmn.shapingLPCOrder );
        }

        /* Bandwidth expansion for synthesis filter shaping */
        SKP_Silk_bwexpander_FLP( &psEncCtrl->AR2[ k * MAX_SHAPE_LPC_ORDER ], psEnc->sCmn.shapingLPCOrder, BWExp2 );

        /* Compute noise shaping filter coefficients */
        SKP_memcpy(
            &psEncCtrl->AR1[ k * MAX_SHAPE_LPC_ORDER ], 
            &psEncCtrl->AR2[ k * MAX_SHAPE_LPC_ORDER ], 
            psEnc->sCmn.shapingLPCOrder * sizeof( SKP_float ) );

        /* Bandwidth expansion for analysis filter shaping */
        SKP_Silk_bwexpander_FLP( &psEncCtrl->AR1[ k * MAX_SHAPE_LPC_ORDER ], psEnc->sCmn.shapingLPCOrder, BWExp1 );

        /* Ratio of prediction gains, in energy domain */
        SKP_Silk_LPC_inverse_pred_gain_FLP( &pre_nrg, &psEncCtrl->AR2[ k * MAX_SHAPE_LPC_ORDER ], psEnc->sCmn.shapingLPCOrder );
        SKP_Silk_LPC_inverse_pred_gain_FLP( &nrg,     &psEncCtrl->AR1[ k * MAX_SHAPE_LPC_ORDER ], psEnc->sCmn.shapingLPCOrder );
        psEncCtrl->GainsPre[ k ] = 1.0f - 0.7f * ( 1.0f - pre_nrg / nrg );

        /* Convert to monic warped prediction coefficients and limit absolute values */
        warped_true2monic_coefs( &psEncCtrl->AR2[ k * MAX_SHAPE_LPC_ORDER ], &psEncCtrl->AR1[ k * MAX_SHAPE_LPC_ORDER ], 
            warping, 3.999f, psEnc->sCmn.shapingLPCOrder );
    }

    /*****************/
    /* Gain tweaking */
    /*****************/
    /* Increase gains during low speech activity and put lower limit on gains */
    gain_mult = ( SKP_float )pow( 2.0f, -0.16f * SNR_adj_dB );
    gain_add  = ( SKP_float )pow( 2.0f,  0.16f * NOISE_FLOOR_dB ) + 
                ( SKP_float )pow( 2.0f,  0.16f * RELATIVE_MIN_GAIN_dB ) * psEnc->avgGain;
    for( k = 0; k < NB_SUBFR; k++ ) {
        psEncCtrl->Gains[ k ] *= gain_mult;
        psEncCtrl->Gains[ k ] += gain_add;
        psEnc->avgGain += psEnc->speech_activity * GAIN_SMOOTHING_COEF * ( psEncCtrl->Gains[ k ] - psEnc->avgGain );
    }

    /************************************************/
    /* Decrease level during fricatives (de-essing) */
    /************************************************/
    gain_mult = 1.0f + INPUT_TILT + psEncCtrl->coding_quality * HIGH_RATE_INPUT_TILT;
    if( psEncCtrl->input_tilt <= 0.0f && psEncCtrl->sCmn.sigtype == SIG_TYPE_UNVOICED ) {
        SKP_float essStrength = -psEncCtrl->input_tilt * psEnc->speech_activity * ( 1.0f - psEncCtrl->sparseness );
        if( psEnc->sCmn.fs_kHz == 24 ) {
            gain_mult *= ( SKP_float )pow( 2.0f, -0.16f * DE_ESSER_COEF_SWB_dB * essStrength );
        } else if( psEnc->sCmn.fs_kHz == 16 ) {
            gain_mult *= (SKP_float)pow( 2.0f, -0.16f * DE_ESSER_COEF_WB_dB * essStrength );
        } else {
            SKP_assert( psEnc->sCmn.fs_kHz == 12 || psEnc->sCmn.fs_kHz == 8 );
        }
    }

    for( k = 0; k < NB_SUBFR; k++ ) {
        psEncCtrl->GainsPre[ k ] *= gain_mult;
    }

    /************************************************/
    /* Control low-frequency shaping and noise tilt */
    /************************************************/
    /* Less low frequency shaping for noisy inputs */
    strength = LOW_FREQ_SHAPING * ( 1.0f + LOW_QUALITY_LOW_FREQ_SHAPING_DECR * ( psEncCtrl->input_quality_bands[ 0 ] - 1.0f ) );
    if( psEncCtrl->sCmn.sigtype == SIG_TYPE_VOICED ) {
        /* Reduce low frequencies quantization noise for periodic signals, depending on pitch lag */
        /*f = 400; freqz([1, -0.98 + 2e-4 * f], [1, -0.97 + 7e-4 * f], 2^12, Fs); axis([0, 1000, -10, 1])*/
        for( k = 0; k < NB_SUBFR; k++ ) {
            b = 0.2f / psEnc->sCmn.fs_kHz + 3.0f / psEncCtrl->sCmn.pitchL[ k ];
            psEncCtrl->LF_MA_shp[ k ] = -1.0f + b;
            psEncCtrl->LF_AR_shp[ k ] =  1.0f - b - b * strength;
        }
        Tilt = - HP_NOISE_COEF - 
            (1 - HP_NOISE_COEF) * HARM_HP_NOISE_COEF * psEnc->speech_activity;
    } else {
        b = 1.3f / psEnc->sCmn.fs_kHz;
        psEncCtrl->LF_MA_shp[ 0 ] = -1.0f + b;
        psEncCtrl->LF_AR_shp[ 0 ] =  1.0f - b - b * strength * 0.6f;
        for( k = 1; k < NB_SUBFR; k++ ) {
            psEncCtrl->LF_MA_shp[ k ] = psEncCtrl->LF_MA_shp[ 0 ];
            psEncCtrl->LF_AR_shp[ k ] = psEncCtrl->LF_AR_shp[ 0 ];
        }
        Tilt = -HP_NOISE_COEF;
    }

    /****************************/
    /* HARMONIC SHAPING CONTROL */
    /****************************/
    /* Control boosting of harmonic frequencies */
    HarmBoost = LOW_RATE_HARMONIC_BOOST * ( 1.0f - psEncCtrl->coding_quality ) * psEnc->LTPCorr;

    /* More harmonic boost for noisy input signals */
    HarmBoost += LOW_INPUT_QUALITY_HARMONIC_BOOST * ( 1.0f - psEncCtrl->input_quality );

    if( USE_HARM_SHAPING && psEncCtrl->sCmn.sigtype == SIG_TYPE_VOICED ) {
        /* Harmonic noise shaping */
        HarmShapeGain = HARMONIC_SHAPING;

        /* More harmonic noise shaping for high bitrates or noisy input */
        HarmShapeGain += HIGH_RATE_OR_LOW_QUALITY_HARMONIC_SHAPING * 
            ( 1.0f - ( 1.0f - psEncCtrl->coding_quality ) * psEncCtrl->input_quality );

        /* Less harmonic noise shaping for less periodic signals */
        HarmShapeGain *= ( SKP_float )sqrt( psEnc->LTPCorr );
    } else {
        HarmShapeGain = 0.0f;
    }

    /*************************/
    /* Smooth over subframes */
    /*************************/
    for( k = 0; k < NB_SUBFR; k++ ) {
        psShapeSt->HarmBoost_smth     += SUBFR_SMTH_COEF * ( HarmBoost - psShapeSt->HarmBoost_smth );
        psEncCtrl->HarmBoost[ k ]      = psShapeSt->HarmBoost_smth;
        psShapeSt->HarmShapeGain_smth += SUBFR_SMTH_COEF * ( HarmShapeGain - psShapeSt->HarmShapeGain_smth );
        psEncCtrl->HarmShapeGain[ k ]  = psShapeSt->HarmShapeGain_smth;
        psShapeSt->Tilt_smth          += SUBFR_SMTH_COEF * ( Tilt - psShapeSt->Tilt_smth );
        psEncCtrl->Tilt[ k ]           = psShapeSt->Tilt_smth;
    }
}
