/src/opus/silk/float/noise_shape_analysis_FLP.c

Source
/***********************************************************************
Copyright (c) 2006-2011, Skype Limited. All rights reserved.
Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions
are met:
- Redistributions of source code must retain the above copyright notice,
this list of conditions and the following disclaimer.
- Redistributions in binary form must reproduce the above copyright
notice, this list of conditions and the following disclaimer in the
documentation and/or other materials provided with the distribution.
- Neither the name of Internet Society, IETF or IETF Trust, nor the
names of specific contributors, may be used to endorse or promote
products derived from this software without specific prior written
permission.
THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
POSSIBILITY OF SUCH DAMAGE.
***********************************************************************/

#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,
    silk_float           lambda,
    silk_float           limit,
    opus_int             order
) {
    opus_int   i, iter, ind = 0;
    silk_float tmp, maxabs, chirp, gain;

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

    /* Limit */
    for( iter = 0; iter < 10; iter++ ) {
        /* Find maximum absolute value */
        maxabs = -1.0f;
        for( i = 0; i < order; i++ ) {
            tmp = silk_abs_float( coefs[ 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[ i - 1 ] += lambda * coefs[ i ];
        }
        gain = 1.0f / gain;
        for( i = 0; i < order; i++ ) {
            coefs[ i ] *= gain;
        }

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

        /* Convert to monic warped coefficients */
        for( i = order - 1; i > 0; i-- ) {
            coefs[ i - 1 ] -= lambda * coefs[ i ];
        }
        gain = ( 1.0f - lambda * lambda ) / ( 1.0f + lambda * coefs[ 0 ] );
        for( i = 0; i < order; i++ ) {
            coefs[ i ] *= gain;
        }
    }
    silk_assert( 0 );
}

static OPUS_INLINE void limit_coefs(
    silk_float           *coefs,
    silk_float           limit,
    opus_int             order
) {
    opus_int   i, iter, ind = 0;
    silk_float tmp, maxabs, chirp;

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

        /* Apply bandwidth expansion */
        chirp = 0.99f - ( 0.8f + 0.1f * iter ) * ( maxabs - limit ) / ( maxabs * ( ind + 1 ) );
        silk_bwexpander_FLP( coefs, order, chirp );
    }
    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, nSegs;
    silk_float   SNR_adj_dB, HarmShapeGain, Tilt;
    silk_float   nrg, log_energy, log_energy_prev, energy_variation;
    silk_float   BWExp, gain_mult, gain_add, strength, b, warping;
    silk_float   x_windowed[ SHAPE_LPC_WIN_MAX ];
    silk_float   auto_corr[ MAX_SHAPE_LPC_ORDER + 1 ];
    silk_float   rc[ 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;
    } 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;
        nSegs = silk_SMULBB( SUB_FRAME_LENGTH_MS, psEnc->sCmn.nb_subfr ) / 2;
        for( k = 0; k < nSegs; 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;
        }

        /* Set quantization offset depending on sparseness measure */
        if( energy_variation > ENERGY_VARIATION_THRESHOLD_QNT_OFFSET * (nSegs-1) ) {
            psEnc->sCmn.indices.quantOffsetType = 0;
        } else {
            psEnc->sCmn.indices.quantOffsetType = 1;
        }
    }

    /*******************************/
    /* 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 */
    BWExp = BANDWIDTH_EXPANSION / ( 1.0f + strength * strength );

    /* 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;

    /********************************************/
    /* 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, psEnc->sCmn.arch );
        }

        /* Add white noise, as a fraction of energy */
        auto_corr[ 0 ] += auto_corr[ 0 ] * SHAPE_WHITE_NOISE_FRACTION + 1.0f;

        /* Convert correlations to prediction coefficients, and compute residual energy */
        nrg = silk_schur_FLP( rc, auto_corr, psEnc->sCmn.shapingLPCOrder );
        silk_k2a_FLP( &psEncCtrl->AR[ k * MAX_SHAPE_LPC_ORDER ], rc, 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->AR[ k * MAX_SHAPE_LPC_ORDER ], warping, psEnc->sCmn.shapingLPCOrder );
        }

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

        if( psEnc->sCmn.warping_Q16 > 0 ) {
            /* Convert to monic warped prediction coefficients and limit absolute values */
            warped_true2monic_coefs( &psEncCtrl->AR[ k * MAX_SHAPE_LPC_ORDER ], warping, 3.999f, psEnc->sCmn.shapingLPCOrder );
        } else {
            /* Limit absolute values */
            limit_coefs( &psEncCtrl->AR[ k * MAX_SHAPE_LPC_ORDER ], 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;
    }

    /************************************************/
    /* 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 */
    /****************************/
    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->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;
    }
}

Coverage Report

Created: 2026-09-28 07:55

Line	Count	Source
1		/***********************************************************************
2		Copyright (c) 2006-2011, Skype Limited. All rights reserved.
3		Redistribution and use in source and binary forms, with or without
4		modification, are permitted provided that the following conditions
5		are met:
6		- Redistributions of source code must retain the above copyright notice,
7		this list of conditions and the following disclaimer.
8		- Redistributions in binary form must reproduce the above copyright
9		notice, this list of conditions and the following disclaimer in the
10		documentation and/or other materials provided with the distribution.
11		- Neither the name of Internet Society, IETF or IETF Trust, nor the
12		names of specific contributors, may be used to endorse or promote
13		products derived from this software without specific prior written
14		permission.
15		THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
16		AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
17		IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
18		ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
19		LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
20		CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
21		SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
22		INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
23		CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
24		ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
25		POSSIBILITY OF SUCH DAMAGE.
26		***********************************************************************/
27
28		#ifdef HAVE_CONFIG_H
29		#include "config.h"
30		#endif
31
32		#include "main_FLP.h"
33		#include "tuning_parameters.h"
34
35		/* Compute gain to make warped filter coefficients have a zero mean log frequency response on a */
36		/* non-warped frequency scale. (So that it can be implemented with a minimum-phase monic filter.) */
37		/* Note: A monic filter is one with the first coefficient equal to 1.0. In Silk we omit the first */
38		/* coefficient in an array of coefficients, for monic filters. */
39		static OPUS_INLINE silk_float warped_gain(
40		const silk_float *coefs,
41		silk_float lambda,
42		opus_int order
43	534k	) {
44	534k	opus_int i;
45	534k	silk_float gain;
46
47	534k	lambda = -lambda;
48	534k	gain = coefs[ order - 1 ];
49	11.2M	for( i = order - 2; i >= 0; i-- ) {
50	10.7M	gain = lambda * gain + coefs[ i ];
51	10.7M	}
52	534k	return (silk_float)( 1.0f / ( 1.0f - lambda * gain ) );
53	534k	}
54
55		/* Convert warped filter coefficients to monic pseudo-warped coefficients and limit maximum */
56		/* amplitude of monic warped coefficients by using bandwidth expansion on the true coefficients */
57		static OPUS_INLINE void warped_true2monic_coefs(
58		silk_float *coefs,
59		silk_float lambda,
60		silk_float limit,
61		opus_int order
62	534k	) {
63	534k	opus_int i, iter, ind = 0;
64	534k	silk_float tmp, maxabs, chirp, gain;
65
66		/* Convert to monic coefficients */
67	11.2M	for( i = order - 1; i > 0; i-- ) {
68	10.7M	coefs[ i - 1 ] -= lambda * coefs[ i ];
69	10.7M	}
70	534k	gain = ( 1.0f - lambda * lambda ) / ( 1.0f + lambda * coefs[ 0 ] );
71	11.7M	for( i = 0; i < order; i++ ) {
72	11.2M	coefs[ i ] *= gain;
73	11.2M	}
74
75		/* Limit */
76	536k	for( iter = 0; iter < 10; iter++ ) {
77		/* Find maximum absolute value */
78	536k	maxabs = -1.0f;
79	11.8M	for( i = 0; i < order; i++ ) {
80	11.3M	tmp = silk_abs_float( coefs[ i ] );
81	11.3M	if( tmp > maxabs ) {
82	848k	maxabs = tmp;
83	848k	ind = i;
84	848k	}
85	11.3M	}
86	536k	if( maxabs <= limit ) {
87		/* Coefficients are within range - done */
88	534k	return;
89	534k	}
90
91		/* Convert back to true warped coefficients */
92	52.1k	for( i = 1; i < order; i++ ) {
93	49.6k	coefs[ i - 1 ] += lambda * coefs[ i ];
94	49.6k	}
95	2.44k	gain = 1.0f / gain;
96	54.5k	for( i = 0; i < order; i++ ) {
97	52.1k	coefs[ i ] *= gain;
98	52.1k	}
99
100		/* Apply bandwidth expansion */
101	2.44k	chirp = 0.99f - ( 0.8f + 0.1f * iter ) * ( maxabs - limit ) / ( maxabs * ( ind + 1 ) );
102	2.44k	silk_bwexpander_FLP( coefs, order, chirp );
103
104		/* Convert to monic warped coefficients */
105	52.1k	for( i = order - 1; i > 0; i-- ) {
106	49.6k	coefs[ i - 1 ] -= lambda * coefs[ i ];
107	49.6k	}
108	2.44k	gain = ( 1.0f - lambda * lambda ) / ( 1.0f + lambda * coefs[ 0 ] );
109	54.5k	for( i = 0; i < order; i++ ) {
110	52.1k	coefs[ i ] *= gain;
111	52.1k	}
112	2.44k	}
113	0	silk_assert( 0 );
114	0	}
115
116		static OPUS_INLINE void limit_coefs(
117		silk_float *coefs,
118		silk_float limit,
119		opus_int order
120	253k	) {
121	253k	opus_int i, iter, ind = 0;
122	253k	silk_float tmp, maxabs, chirp;
123
124	255k	for( iter = 0; iter < 10; iter++ ) {
125		/* Find maximum absolute value */
126	255k	maxabs = -1.0f;
127	3.48M	for( i = 0; i < order; i++ ) {
128	3.23M	tmp = silk_abs_float( coefs[ i ] );
129	3.23M	if( tmp > maxabs ) {
130	436k	maxabs = tmp;
131	436k	ind = i;
132	436k	}
133	3.23M	}
134	255k	if( maxabs <= limit ) {
135		/* Coefficients are within range - done */
136	253k	return;
137	253k	}
138
139		/* Apply bandwidth expansion */
140	1.54k	chirp = 0.99f - ( 0.8f + 0.1f * iter ) * ( maxabs - limit ) / ( maxabs * ( ind + 1 ) );
141	1.54k	silk_bwexpander_FLP( coefs, order, chirp );
142	1.54k	}
143	0	silk_assert( 0 );
144	0	}
145
146		/* Compute noise shaping coefficients and initial gain values */
147		void silk_noise_shape_analysis_FLP(
148		silk_encoder_state_FLP psEnc, / I/O Encoder state FLP */
149		silk_encoder_control_FLP psEncCtrl, / I/O Encoder control FLP */
150		const silk_float pitch_res, / I LPC residual from pitch analysis */
151		const silk_float x / I Input signal [frame_length + la_shape] */
152		)
153	224k	{
154	224k	silk_shape_state_FLP *psShapeSt = &psEnc->sShape;
155	224k	opus_int k, nSamples, nSegs;
156	224k	silk_float SNR_adj_dB, HarmShapeGain, Tilt;
157	224k	silk_float nrg, log_energy, log_energy_prev, energy_variation;
158	224k	silk_float BWExp, gain_mult, gain_add, strength, b, warping;
159	224k	silk_float x_windowed[ SHAPE_LPC_WIN_MAX ];
160	224k	silk_float auto_corr[ MAX_SHAPE_LPC_ORDER + 1 ];
161	224k	silk_float rc[ MAX_SHAPE_LPC_ORDER + 1 ];
162	224k	const silk_float x_ptr, pitch_res_ptr;
163
164		/* Point to start of first LPC analysis block */
165	224k	x_ptr = x - psEnc->sCmn.la_shape;
166
167		/****************/
168		/* GAIN CONTROL */
169		/****************/
170	224k	SNR_adj_dB = psEnc->sCmn.SNR_dB_Q7 * ( 1 / 128.0f );
171
172		/* Input quality is the average of the quality in the lowest two VAD bands */
173	224k	psEncCtrl->input_quality = 0.5f * ( psEnc->sCmn.input_quality_bands_Q15[ 0 ] + psEnc->sCmn.input_quality_bands_Q15[ 1 ] ) * ( 1.0f / 32768.0f );
174
175		/* Coding quality level, between 0.0 and 1.0 */
176	224k	psEncCtrl->coding_quality = silk_sigmoid( 0.25f * ( SNR_adj_dB - 20.0f ) );
177
178	224k	if( psEnc->sCmn.useCBR == 0 ) {
179		/* Reduce coding SNR during low speech activity */
180	104k	b = 1.0f - psEnc->sCmn.speech_activity_Q8 * ( 1.0f / 256.0f );
181	104k	SNR_adj_dB -= BG_SNR_DECR_dB * psEncCtrl->coding_quality * ( 0.5f + 0.5f * psEncCtrl->input_quality ) * b * b;
182	104k	}
183
184	224k	if( psEnc->sCmn.indices.signalType == TYPE_VOICED ) {
185		/* Reduce gains for periodic signals */
186	28.9k	SNR_adj_dB += HARM_SNR_INCR_dB * psEnc->LTPCorr;
187	195k	} else {
188		/* For unvoiced signals and low-quality input, adjust the quality slower than SNR_dB setting */
189	195k	SNR_adj_dB += ( -0.4f * psEnc->sCmn.SNR_dB_Q7 * ( 1 / 128.0f ) + 6.0f ) * ( 1.0f - psEncCtrl->input_quality );
190	195k	}
191
192		/*************************/
193		/* SPARSENESS PROCESSING */
194		/*************************/
195		/* Set quantizer offset */
196	224k	if( psEnc->sCmn.indices.signalType == TYPE_VOICED ) {
197		/* Initially set to 0; may be overruled in process_gains(..) */
198	28.9k	psEnc->sCmn.indices.quantOffsetType = 0;
199	195k	} else {
200		/* Sparseness measure, based on relative fluctuations of energy per 2 milliseconds */
201	195k	nSamples = 2 * psEnc->sCmn.fs_kHz;
202	195k	energy_variation = 0.0f;
203	195k	log_energy_prev = 0.0f;
204	195k	pitch_res_ptr = pitch_res;
205	195k	nSegs = silk_SMULBB( SUB_FRAME_LENGTH_MS, psEnc->sCmn.nb_subfr ) / 2;
206	1.87M	for( k = 0; k < nSegs; k++ ) {
207	1.68M	nrg = ( silk_float )nSamples + ( silk_float )silk_energy_FLP( pitch_res_ptr, nSamples );
208	1.68M	log_energy = silk_log2( nrg );
209	1.68M	if( k > 0 ) {
210	1.48M	energy_variation += silk_abs_float( log_energy - log_energy_prev );
211	1.48M	}
212	1.68M	log_energy_prev = log_energy;
213	1.68M	pitch_res_ptr += nSamples;
214	1.68M	}
215
216		/* Set quantization offset depending on sparseness measure */
217	195k	if( energy_variation > ENERGY_VARIATION_THRESHOLD_QNT_OFFSET * (nSegs-1) ) {
218	147k	psEnc->sCmn.indices.quantOffsetType = 0;
219	147k	} else {
220	48.3k	psEnc->sCmn.indices.quantOffsetType = 1;
221	48.3k	}
222	195k	}
223
224		/*******************************/
225		/* Control bandwidth expansion */
226		/*******************************/
227		/* More BWE for signals with high prediction gain */
228	224k	strength = FIND_PITCH_WHITE_NOISE_FRACTION * psEncCtrl->predGain; /* between 0.0 and 1.0 */
229	224k	BWExp = BANDWIDTH_EXPANSION / ( 1.0f + strength * strength );
230
231		/* Slightly more warping in analysis will move quantization noise up in frequency, where it's better masked */
232	224k	warping = (silk_float)psEnc->sCmn.warping_Q16 / 65536.0f + 0.01f * psEncCtrl->coding_quality;
233
234		/********************************************/
235		/* Compute noise shaping AR coefs and gains */
236		/********************************************/
237	1.01M	for( k = 0; k < psEnc->sCmn.nb_subfr; k++ ) {
238		/* Apply window: sine slope followed by flat part followed by cosine slope */
239	788k	opus_int shift, slope_part, flat_part;
240	788k	flat_part = psEnc->sCmn.fs_kHz * 3;
241	788k	slope_part = ( psEnc->sCmn.shapeWinLength - flat_part ) / 2;
242
243	788k	silk_apply_sine_window_FLP( x_windowed, x_ptr, 1, slope_part );
244	788k	shift = slope_part;
245	788k	silk_memcpy( x_windowed + shift, x_ptr + shift, flat_part * sizeof(silk_float) );
246	788k	shift += flat_part;
247	788k	silk_apply_sine_window_FLP( x_windowed + shift, x_ptr + shift, 2, slope_part );
248
249		/* Update pointer: next LPC analysis block */
250	788k	x_ptr += psEnc->sCmn.subfr_length;
251
252	788k	if( psEnc->sCmn.warping_Q16 > 0 ) {
253		/* Calculate warped auto correlation */
254	534k	silk_warped_autocorrelation_FLP( auto_corr, x_windowed, warping,
255	534k	psEnc->sCmn.shapeWinLength, psEnc->sCmn.shapingLPCOrder );
256	534k	} else {
257		/* Calculate regular auto correlation */
258	253k	silk_autocorrelation_FLP( auto_corr, x_windowed, psEnc->sCmn.shapeWinLength, psEnc->sCmn.shapingLPCOrder + 1, psEnc->sCmn.arch );
259	253k	}
260
261		/* Add white noise, as a fraction of energy */
262	788k	auto_corr[ 0 ] += auto_corr[ 0 ] * SHAPE_WHITE_NOISE_FRACTION + 1.0f;
263
264		/* Convert correlations to prediction coefficients, and compute residual energy */
265	788k	nrg = silk_schur_FLP( rc, auto_corr, psEnc->sCmn.shapingLPCOrder );
266	788k	silk_k2a_FLP( &psEncCtrl->AR[ k * MAX_SHAPE_LPC_ORDER ], rc, psEnc->sCmn.shapingLPCOrder );
267	788k	psEncCtrl->Gains[ k ] = ( silk_float )sqrt( nrg );
268
269	788k	if( psEnc->sCmn.warping_Q16 > 0 ) {
270		/* Adjust gain for warping */
271	534k	psEncCtrl->Gains[ k ] = warped_gain( &psEncCtrl->AR[ k MAX_SHAPE_LPC_ORDER ], warping, psEnc->sCmn.shapingLPCOrder );
272	534k	}
273
274		/* Bandwidth expansion for synthesis filter shaping */
275	788k	silk_bwexpander_FLP( &psEncCtrl->AR[ k * MAX_SHAPE_LPC_ORDER ], psEnc->sCmn.shapingLPCOrder, BWExp );
276
277	788k	if( psEnc->sCmn.warping_Q16 > 0 ) {
278		/* Convert to monic warped prediction coefficients and limit absolute values */
279	534k	warped_true2monic_coefs( &psEncCtrl->AR[ k * MAX_SHAPE_LPC_ORDER ], warping, 3.999f, psEnc->sCmn.shapingLPCOrder );
280	534k	} else {
281		/* Limit absolute values */
282	253k	limit_coefs( &psEncCtrl->AR[ k * MAX_SHAPE_LPC_ORDER ], 3.999f, psEnc->sCmn.shapingLPCOrder );
283	253k	}
284	788k	}
285
286		/*****************/
287		/* Gain tweaking */
288		/*****************/
289		/* Increase gains during low speech activity */
290	224k	gain_mult = (silk_float)pow( 2.0f, -0.16f * SNR_adj_dB );
291	224k	gain_add = (silk_float)pow( 2.0f, 0.16f * MIN_QGAIN_DB );
292	1.01M	for( k = 0; k < psEnc->sCmn.nb_subfr; k++ ) {
293	788k	psEncCtrl->Gains[ k ] *= gain_mult;
294	788k	psEncCtrl->Gains[ k ] += gain_add;
295	788k	}
296
297		/************************************************/
298		/* Control low-frequency shaping and noise tilt */
299		/************************************************/
300		/* Less low frequency shaping for noisy inputs */
301	224k	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 ) );
302	224k	strength = psEnc->sCmn.speech_activity_Q8 ( 1.0f / 256.0f );
303	224k	if( psEnc->sCmn.indices.signalType == TYPE_VOICED ) {
304		/* Reduce low frequencies quantization noise for periodic signals, depending on pitch lag */
305		/f = 400; freqz([1, -0.98 + 2e-4 f], [1, -0.97 + 7e-4 * f], 2^12, Fs); axis([0, 1000, -10, 1])*/
306	144k	for( k = 0; k < psEnc->sCmn.nb_subfr; k++ ) {
307	115k	b = 0.2f / psEnc->sCmn.fs_kHz + 3.0f / psEncCtrl->pitchL[ k ];
308	115k	psEncCtrl->LF_MA_shp[ k ] = -1.0f + b;
309	115k	psEncCtrl->LF_AR_shp[ k ] = 1.0f - b - b * strength;
310	115k	}
311	28.9k	Tilt = - HP_NOISE_COEF -
312	28.9k	(1 - HP_NOISE_COEF) * HARM_HP_NOISE_COEF * psEnc->sCmn.speech_activity_Q8 * ( 1.0f / 256.0f );
313	195k	} else {
314	195k	b = 1.3f / psEnc->sCmn.fs_kHz;
315	195k	psEncCtrl->LF_MA_shp[ 0 ] = -1.0f + b;
316	195k	psEncCtrl->LF_AR_shp[ 0 ] = 1.0f - b - b * strength * 0.6f;
317	672k	for( k = 1; k < psEnc->sCmn.nb_subfr; k++ ) {
318	476k	psEncCtrl->LF_MA_shp[ k ] = psEncCtrl->LF_MA_shp[ 0 ];
319	476k	psEncCtrl->LF_AR_shp[ k ] = psEncCtrl->LF_AR_shp[ 0 ];
320	476k	}
321	195k	Tilt = -HP_NOISE_COEF;
322	195k	}
323
324		/****************************/
325		/* HARMONIC SHAPING CONTROL */
326		/****************************/
327	224k	if( USE_HARM_SHAPING && psEnc->sCmn.indices.signalType == TYPE_VOICED ) {
328		/* Harmonic noise shaping */
329	28.9k	HarmShapeGain = HARMONIC_SHAPING;
330
331		/* More harmonic noise shaping for high bitrates or noisy input */
332	28.9k	HarmShapeGain += HIGH_RATE_OR_LOW_QUALITY_HARMONIC_SHAPING *
333	28.9k	( 1.0f - ( 1.0f - psEncCtrl->coding_quality ) * psEncCtrl->input_quality );
334
335		/* Less harmonic noise shaping for less periodic signals */
336	28.9k	HarmShapeGain *= ( silk_float )sqrt( psEnc->LTPCorr );
337	195k	} else {
338	195k	HarmShapeGain = 0.0f;
339	195k	}
340
341		/*************************/
342		/* Smooth over subframes */
343		/*************************/
344	1.01M	for( k = 0; k < psEnc->sCmn.nb_subfr; k++ ) {
345	788k	psShapeSt->HarmShapeGain_smth += SUBFR_SMTH_COEF * ( HarmShapeGain - psShapeSt->HarmShapeGain_smth );
346	788k	psEncCtrl->HarmShapeGain[ k ] = psShapeSt->HarmShapeGain_smth;
347	788k	psShapeSt->Tilt_smth += SUBFR_SMTH_COEF * ( Tilt - psShapeSt->Tilt_smth );
348	788k	psEncCtrl->Tilt[ k ] = psShapeSt->Tilt_smth;
349	788k	}
350	224k	}