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

 #ifdef HAVE_CONFIG_H

 #include "config.h"

 #endif

 #include "main_FLP.h"

 #include "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.) */

 /* Note: A monic filter is one with the first coefficient equal to 1.0. In Silk we omit the first */

 /* coefficient in an array of coefficients, for monic filters.                                    */

 static OPUS_INLINE silk_float warped_gain(

     const silk_float     *coefs,

     silk_float           lambda,

     opus_int             order

 ) {

     opus_int   i;

     silk_float gain;

     lambda = -lambda;

     gain = coefs[ order - 1 ];

     for( i = order - 2; i >= 0; i-- ) {

         gain = lambda * gain + coefs[ i ];

     }

     return (silk_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 */

 static OPUS_INLINE void warped_true2monic_coefs(

     silk_float           *coefs_syn,

     silk_float           *coefs_ana,

     silk_float           lambda,

     silk_float           limit,

     opus_int             order

 ) {

     opus_int   i, iter, ind = 0;

     silk_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 = silk_max( silk_abs_float( coefs_syn[ i ] ), silk_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 ) );

         silk_bwexpander_FLP( coefs_syn, order, chirp );

         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;

         }

     }

     silk_assert( 0 );

 }

 /* Compute noise shaping coefficients and initial gain values */

 void silk_noise_shape_analysis_FLP(

     silk_encoder_state_FLP          *psEnc,                             /* I/O  Encoder state FLP                           */

     silk_encoder_control_FLP        *psEncCtrl,                         /* I/O  Encoder control FLP                         */

     const silk_float                *pitch_res,                         /* I    LPC residual from pitch analysis            */

     const silk_float                *x                                  /* I    Input signal [frame_length + la_shape]      */

 )

 {

     silk_shape_state_FLP *psShapeSt = &psEnc->sShape;

     opus_int     k, nSamples;

     silk_float   SNR_adj_dB, HarmBoost, HarmShapeGain, Tilt;

     silk_float   nrg, pre_nrg, log_energy, log_energy_prev, energy_variation;

     silk_float   delta, BWExp1, BWExp2, gain_mult, gain_add, strength, b, warping;

     silk_float   x_windowed[ SHAPE_LPC_WIN_MAX ];

     silk_float   auto_corr[ MAX_SHAPE_LPC_ORDER + 1 ];

     const silk_float *x_ptr, *pitch_res_ptr;

     /* Point to start of first LPC analysis block */

     x_ptr = x - psEnc->sCmn.la_shape;

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

     /* GAIN CONTROL */

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

     SNR_adj_dB = psEnc->sCmn.SNR_dB_Q7 * ( 1 / 128.0f );

     /* Input quality is the average of the quality in the lowest two VAD bands */

     psEncCtrl->input_quality = 0.5f * ( psEnc->sCmn.input_quality_bands_Q15[ 0 ] + psEnc->sCmn.input_quality_bands_Q15[ 1 ] ) * ( 1.0f / 32768.0f );

     /* Coding quality level, between 0.0 and 1.0 */

     psEncCtrl->coding_quality = silk_sigmoid( 0.25f * ( SNR_adj_dB - 20.0f ) );

     if( psEnc->sCmn.useCBR == 0 ) {

         /* Reduce coding SNR during low speech activity */

         b = 1.0f - psEnc->sCmn.speech_activity_Q8 * ( 1.0f /  256.0f );

         SNR_adj_dB -= BG_SNR_DECR_dB * psEncCtrl->coding_quality * ( 0.5f + 0.5f * psEncCtrl->input_quality ) * b * b;

     }

     if( psEnc->sCmn.indices.signalType == 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 * psEnc->sCmn.SNR_dB_Q7 * ( 1 / 128.0f ) + 6.0f ) * ( 1.0f - psEncCtrl->input_quality );

     }

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

     /* SPARSENESS PROCESSING */

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

     /* Set quantizer offset */

     if( psEnc->sCmn.indices.signalType == TYPE_VOICED ) {

         /* Initially set to 0; may be overruled in process_gains(..) */

         psEnc->sCmn.indices.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 < silk_SMULBB( SUB_FRAME_LENGTH_MS, psEnc->sCmn.nb_subfr ) / 2; k++ ) {

             nrg = ( silk_float )nSamples + ( silk_float )silk_energy_FLP( pitch_res_ptr, nSamples );

             log_energy = silk_log2( nrg );

             if( k > 0 ) {

                 energy_variation += silk_abs_float( log_energy - log_energy_prev );

             }

             log_energy_prev = log_energy;

             pitch_res_ptr += nSamples;

         }

         psEncCtrl->sparseness = silk_sigmoid( 0.4f * ( energy_variation - 5.0f ) );

         /* Set quantization offset depending on sparseness measure */

         if( psEncCtrl->sparseness > SPARSENESS_THRESHOLD_QNT_OFFSET ) {

             psEnc->sCmn.indices.quantOffsetType = 0;

         } else {

             psEnc->sCmn.indices.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 = (silk_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 < psEnc->sCmn.nb_subfr; k++ ) {

         /* Apply window: sine slope followed by flat part followed by cosine slope */

         opus_int shift, slope_part, flat_part;

         flat_part = psEnc->sCmn.fs_kHz * 3;

         slope_part = ( psEnc->sCmn.shapeWinLength - flat_part ) / 2;

         silk_apply_sine_window_FLP( x_windowed, x_ptr, 1, slope_part );

         shift = slope_part;

         silk_memcpy( x_windowed + shift, x_ptr + shift, flat_part * sizeof(silk_float) );

         shift += flat_part;

         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 */

             silk_warped_autocorrelation_FLP( auto_corr, x_windowed, warping,

                 psEnc->sCmn.shapeWinLength, psEnc->sCmn.shapingLPCOrder );

         } else {

             /* Calculate regular auto correlation */

             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 = silk_levinsondurbin_FLP( &psEncCtrl->AR2[ k * MAX_SHAPE_LPC_ORDER ], auto_corr, psEnc->sCmn.shapingLPCOrder );

         psEncCtrl->Gains[ k ] = ( silk_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 */

         silk_bwexpander_FLP( &psEncCtrl->AR2[ k * MAX_SHAPE_LPC_ORDER ], psEnc->sCmn.shapingLPCOrder, BWExp2 );

         /* Compute noise shaping filter coefficients */

         silk_memcpy(

             &psEncCtrl->AR1[ k * MAX_SHAPE_LPC_ORDER ],

             &psEncCtrl->AR2[ k * MAX_SHAPE_LPC_ORDER ],

             psEnc->sCmn.shapingLPCOrder * sizeof( silk_float ) );

         /* Bandwidth expansion for analysis filter shaping */

         silk_bwexpander_FLP( &psEncCtrl->AR1[ k * MAX_SHAPE_LPC_ORDER ], psEnc->sCmn.shapingLPCOrder, BWExp1 );

         /* Ratio of prediction gains, in energy domain */

         pre_nrg = silk_LPC_inverse_pred_gain_FLP( &psEncCtrl->AR2[ k * MAX_SHAPE_LPC_ORDER ], psEnc->sCmn.shapingLPCOrder );

         nrg     = silk_LPC_inverse_pred_gain_FLP( &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 */

     gain_mult = (silk_float)pow( 2.0f, -0.16f * SNR_adj_dB );

     gain_add  = (silk_float)pow( 2.0f,  0.16f * MIN_QGAIN_DB );

     for( k = 0; k < psEnc->sCmn.nb_subfr; k++ ) {

         psEncCtrl->Gains[ k ] *= gain_mult;

         psEncCtrl->Gains[ k ] += gain_add;

     }

     gain_mult = 1.0f + INPUT_TILT + psEncCtrl->coding_quality * HIGH_RATE_INPUT_TILT;

     for( k = 0; k < psEnc->sCmn.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 * ( psEnc->sCmn.input_quality_bands_Q15[ 0 ] * ( 1.0f / 32768.0f ) - 1.0f ) );

     strength *= psEnc->sCmn.speech_activity_Q8 * ( 1.0f /  256.0f );

     if( psEnc->sCmn.indices.signalType == 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 < psEnc->sCmn.nb_subfr; k++ ) {

             b = 0.2f / psEnc->sCmn.fs_kHz + 3.0f / psEncCtrl->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->sCmn.speech_activity_Q8 * ( 1.0f /  256.0f );

     } 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 < psEnc->sCmn.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 && psEnc->sCmn.indices.signalType == 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 *= ( silk_float )sqrt( psEnc->LTPCorr );

     } else {

         HarmShapeGain = 0.0f;

     }

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

     /* Smooth over subframes */

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

     for( k = 0; k < psEnc->sCmn.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;

     }

 }