331 lines
14 KiB
C
331 lines
14 KiB
C
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/***********************************************************************
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Copyright (c) 2006-2011, Skype Limited. All rights reserved.
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Redistribution and use in source and binary forms, with or without
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modification, are permitted provided that the following conditions
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are met:
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- Redistributions of source code must retain the above copyright notice,
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this list of conditions and the following disclaimer.
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- Redistributions in binary form must reproduce the above copyright
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notice, this list of conditions and the following disclaimer in the
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documentation and/or other materials provided with the distribution.
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- Neither the name of Internet Society, IETF or IETF Trust, nor the
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names of specific contributors, may be used to endorse or promote
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products derived from this software without specific prior written
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permission.
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THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS “AS IS”
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AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
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LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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POSSIBILITY OF SUCH DAMAGE.
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***********************************************************************/
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#ifdef HAVE_CONFIG_H
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#include "config.h"
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#endif
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#include "main.h"
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/* Silk VAD noise level estimation */
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static __inline void silk_VAD_GetNoiseLevels(
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const opus_int32 pX[ VAD_N_BANDS ], /* I subband energies */
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silk_VAD_state *psSilk_VAD /* I/O Pointer to Silk VAD state */
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);
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/**********************************/
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/* Initialization of the Silk VAD */
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/**********************************/
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opus_int silk_VAD_Init( /* O Return value, 0 if success */
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silk_VAD_state *psSilk_VAD /* I/O Pointer to Silk VAD state */
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)
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{
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opus_int b, ret = 0;
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/* reset state memory */
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silk_memset( psSilk_VAD, 0, sizeof( silk_VAD_state ) );
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/* init noise levels */
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/* Initialize array with approx pink noise levels (psd proportional to inverse of frequency) */
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for( b = 0; b < VAD_N_BANDS; b++ ) {
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psSilk_VAD->NoiseLevelBias[ b ] = silk_max_32( silk_DIV32_16( VAD_NOISE_LEVELS_BIAS, b + 1 ), 1 );
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}
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/* Initialize state */
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for( b = 0; b < VAD_N_BANDS; b++ ) {
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psSilk_VAD->NL[ b ] = silk_MUL( 100, psSilk_VAD->NoiseLevelBias[ b ] );
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psSilk_VAD->inv_NL[ b ] = silk_DIV32( silk_int32_MAX, psSilk_VAD->NL[ b ] );
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}
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psSilk_VAD->counter = 15;
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/* init smoothed energy-to-noise ratio*/
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for( b = 0; b < VAD_N_BANDS; b++ ) {
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psSilk_VAD->NrgRatioSmth_Q8[ b ] = 100 * 256; /* 100 * 256 --> 20 dB SNR */
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}
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return( ret );
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}
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/* Weighting factors for tilt measure */
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static const opus_int32 tiltWeights[ VAD_N_BANDS ] = { 30000, 6000, -12000, -12000 };
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/***************************************/
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/* Get the speech activity level in Q8 */
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/***************************************/
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opus_int silk_VAD_GetSA_Q8( /* O Return value, 0 if success */
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silk_encoder_state *psEncC, /* I/O Encoder state */
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const opus_int16 pIn[] /* I PCM input */
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)
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{
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opus_int SA_Q15, pSNR_dB_Q7, input_tilt;
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opus_int decimated_framelength, dec_subframe_length, dec_subframe_offset, SNR_Q7, i, b, s;
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opus_int32 sumSquared, smooth_coef_Q16;
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opus_int16 HPstateTmp;
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opus_int16 X[ VAD_N_BANDS ][ MAX_FRAME_LENGTH / 2 ];
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opus_int32 Xnrg[ VAD_N_BANDS ];
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opus_int32 NrgToNoiseRatio_Q8[ VAD_N_BANDS ];
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opus_int32 speech_nrg, x_tmp;
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opus_int ret = 0;
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silk_VAD_state *psSilk_VAD = &psEncC->sVAD;
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/* Safety checks */
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silk_assert( VAD_N_BANDS == 4 );
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silk_assert( MAX_FRAME_LENGTH >= psEncC->frame_length );
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silk_assert( psEncC->frame_length <= 512 );
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silk_assert( psEncC->frame_length == 8 * silk_RSHIFT( psEncC->frame_length, 3 ) );
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/***********************/
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/* Filter and Decimate */
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/***********************/
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/* 0-8 kHz to 0-4 kHz and 4-8 kHz */
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silk_ana_filt_bank_1( pIn, &psSilk_VAD->AnaState[ 0 ], &X[ 0 ][ 0 ], &X[ 3 ][ 0 ], psEncC->frame_length );
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/* 0-4 kHz to 0-2 kHz and 2-4 kHz */
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silk_ana_filt_bank_1( &X[ 0 ][ 0 ], &psSilk_VAD->AnaState1[ 0 ], &X[ 0 ][ 0 ], &X[ 2 ][ 0 ], silk_RSHIFT( psEncC->frame_length, 1 ) );
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/* 0-2 kHz to 0-1 kHz and 1-2 kHz */
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silk_ana_filt_bank_1( &X[ 0 ][ 0 ], &psSilk_VAD->AnaState2[ 0 ], &X[ 0 ][ 0 ], &X[ 1 ][ 0 ], silk_RSHIFT( psEncC->frame_length, 2 ) );
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/*********************************************/
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/* HP filter on lowest band (differentiator) */
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/*********************************************/
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decimated_framelength = silk_RSHIFT( psEncC->frame_length, 3 );
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X[ 0 ][ decimated_framelength - 1 ] = silk_RSHIFT( X[ 0 ][ decimated_framelength - 1 ], 1 );
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HPstateTmp = X[ 0 ][ decimated_framelength - 1 ];
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for( i = decimated_framelength - 1; i > 0; i-- ) {
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X[ 0 ][ i - 1 ] = silk_RSHIFT( X[ 0 ][ i - 1 ], 1 );
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X[ 0 ][ i ] -= X[ 0 ][ i - 1 ];
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}
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X[ 0 ][ 0 ] -= psSilk_VAD->HPstate;
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psSilk_VAD->HPstate = HPstateTmp;
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/*************************************/
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/* Calculate the energy in each band */
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/*************************************/
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for( b = 0; b < VAD_N_BANDS; b++ ) {
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/* Find the decimated framelength in the non-uniformly divided bands */
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decimated_framelength = silk_RSHIFT( psEncC->frame_length, silk_min_int( VAD_N_BANDS - b, VAD_N_BANDS - 1 ) );
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/* Split length into subframe lengths */
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dec_subframe_length = silk_RSHIFT( decimated_framelength, VAD_INTERNAL_SUBFRAMES_LOG2 );
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dec_subframe_offset = 0;
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/* Compute energy per sub-frame */
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/* initialize with summed energy of last subframe */
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Xnrg[ b ] = psSilk_VAD->XnrgSubfr[ b ];
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for( s = 0; s < VAD_INTERNAL_SUBFRAMES; s++ ) {
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sumSquared = 0;
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for( i = 0; i < dec_subframe_length; i++ ) {
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/* The energy will be less than dec_subframe_length * ( silk_int16_MIN / 8 ) ^ 2. */
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/* Therefore we can accumulate with no risk of overflow (unless dec_subframe_length > 128) */
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x_tmp = silk_RSHIFT( X[ b ][ i + dec_subframe_offset ], 3 );
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sumSquared = silk_SMLABB( sumSquared, x_tmp, x_tmp );
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/* Safety check */
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silk_assert( sumSquared >= 0 );
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}
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/* Add/saturate summed energy of current subframe */
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if( s < VAD_INTERNAL_SUBFRAMES - 1 ) {
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Xnrg[ b ] = silk_ADD_POS_SAT32( Xnrg[ b ], sumSquared );
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} else {
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/* Look-ahead subframe */
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Xnrg[ b ] = silk_ADD_POS_SAT32( Xnrg[ b ], silk_RSHIFT( sumSquared, 1 ) );
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}
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dec_subframe_offset += dec_subframe_length;
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}
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psSilk_VAD->XnrgSubfr[ b ] = sumSquared;
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}
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/********************/
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/* Noise estimation */
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/********************/
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silk_VAD_GetNoiseLevels( &Xnrg[ 0 ], psSilk_VAD );
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/***********************************************/
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/* Signal-plus-noise to noise ratio estimation */
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/***********************************************/
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sumSquared = 0;
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input_tilt = 0;
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for( b = 0; b < VAD_N_BANDS; b++ ) {
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speech_nrg = Xnrg[ b ] - psSilk_VAD->NL[ b ];
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if( speech_nrg > 0 ) {
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/* Divide, with sufficient resolution */
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if( ( Xnrg[ b ] & 0xFF800000 ) == 0 ) {
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NrgToNoiseRatio_Q8[ b ] = silk_DIV32( silk_LSHIFT( Xnrg[ b ], 8 ), psSilk_VAD->NL[ b ] + 1 );
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} else {
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NrgToNoiseRatio_Q8[ b ] = silk_DIV32( Xnrg[ b ], silk_RSHIFT( psSilk_VAD->NL[ b ], 8 ) + 1 );
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}
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/* Convert to log domain */
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SNR_Q7 = silk_lin2log( NrgToNoiseRatio_Q8[ b ] ) - 8 * 128;
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/* Sum-of-squares */
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sumSquared = silk_SMLABB( sumSquared, SNR_Q7, SNR_Q7 ); /* Q14 */
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/* Tilt measure */
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if( speech_nrg < ( (opus_int32)1 << 20 ) ) {
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/* Scale down SNR value for small subband speech energies */
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SNR_Q7 = silk_SMULWB( silk_LSHIFT( silk_SQRT_APPROX( speech_nrg ), 6 ), SNR_Q7 );
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}
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input_tilt = silk_SMLAWB( input_tilt, tiltWeights[ b ], SNR_Q7 );
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} else {
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NrgToNoiseRatio_Q8[ b ] = 256;
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}
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}
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/* Mean-of-squares */
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sumSquared = silk_DIV32_16( sumSquared, VAD_N_BANDS ); /* Q14 */
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/* Root-mean-square approximation, scale to dBs, and write to output pointer */
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pSNR_dB_Q7 = (opus_int16)( 3 * silk_SQRT_APPROX( sumSquared ) ); /* Q7 */
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/*********************************/
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/* Speech Probability Estimation */
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/*********************************/
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SA_Q15 = silk_sigm_Q15( silk_SMULWB( VAD_SNR_FACTOR_Q16, pSNR_dB_Q7 ) - VAD_NEGATIVE_OFFSET_Q5 );
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/**************************/
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/* Frequency Tilt Measure */
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/**************************/
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psEncC->input_tilt_Q15 = silk_LSHIFT( silk_sigm_Q15( input_tilt ) - 16384, 1 );
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/**************************************************/
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/* Scale the sigmoid output based on power levels */
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/**************************************************/
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speech_nrg = 0;
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for( b = 0; b < VAD_N_BANDS; b++ ) {
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/* Accumulate signal-without-noise energies, higher frequency bands have more weight */
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speech_nrg += ( b + 1 ) * silk_RSHIFT( Xnrg[ b ] - psSilk_VAD->NL[ b ], 4 );
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}
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/* Power scaling */
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if( speech_nrg <= 0 ) {
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SA_Q15 = silk_RSHIFT( SA_Q15, 1 );
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} else if( speech_nrg < 32768 ) {
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if( psEncC->frame_length == 10 * psEncC->fs_kHz ) {
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speech_nrg = silk_LSHIFT_SAT32( speech_nrg, 16 );
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} else {
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speech_nrg = silk_LSHIFT_SAT32( speech_nrg, 15 );
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}
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/* square-root */
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speech_nrg = silk_SQRT_APPROX( speech_nrg );
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SA_Q15 = silk_SMULWB( 32768 + speech_nrg, SA_Q15 );
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}
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/* Copy the resulting speech activity in Q8 */
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psEncC->speech_activity_Q8 = silk_min_int( silk_RSHIFT( SA_Q15, 7 ), silk_uint8_MAX );
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/***********************************/
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/* Energy Level and SNR estimation */
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/***********************************/
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/* Smoothing coefficient */
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smooth_coef_Q16 = silk_SMULWB( VAD_SNR_SMOOTH_COEF_Q18, silk_SMULWB( (opus_int32)SA_Q15, SA_Q15 ) );
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if( psEncC->frame_length == 10 * psEncC->fs_kHz ) {
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smooth_coef_Q16 >>= 1;
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}
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for( b = 0; b < VAD_N_BANDS; b++ ) {
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/* compute smoothed energy-to-noise ratio per band */
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psSilk_VAD->NrgRatioSmth_Q8[ b ] = silk_SMLAWB( psSilk_VAD->NrgRatioSmth_Q8[ b ],
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NrgToNoiseRatio_Q8[ b ] - psSilk_VAD->NrgRatioSmth_Q8[ b ], smooth_coef_Q16 );
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/* signal to noise ratio in dB per band */
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SNR_Q7 = 3 * ( silk_lin2log( psSilk_VAD->NrgRatioSmth_Q8[b] ) - 8 * 128 );
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/* quality = sigmoid( 0.25 * ( SNR_dB - 16 ) ); */
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psEncC->input_quality_bands_Q15[ b ] = silk_sigm_Q15( silk_RSHIFT( SNR_Q7 - 16 * 128, 4 ) );
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}
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return( ret );
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}
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/**************************/
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/* Noise level estimation */
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/**************************/
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static __inline void silk_VAD_GetNoiseLevels(
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const opus_int32 pX[ VAD_N_BANDS ], /* I subband energies */
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silk_VAD_state *psSilk_VAD /* I/O Pointer to Silk VAD state */
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)
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{
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opus_int k;
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opus_int32 nl, nrg, inv_nrg;
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opus_int coef, min_coef;
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/* Initially faster smoothing */
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if( psSilk_VAD->counter < 1000 ) { /* 1000 = 20 sec */
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min_coef = silk_DIV32_16( silk_int16_MAX, silk_RSHIFT( psSilk_VAD->counter, 4 ) + 1 );
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} else {
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min_coef = 0;
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}
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for( k = 0; k < VAD_N_BANDS; k++ ) {
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/* Get old noise level estimate for current band */
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nl = psSilk_VAD->NL[ k ];
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silk_assert( nl >= 0 );
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/* Add bias */
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nrg = silk_ADD_POS_SAT32( pX[ k ], psSilk_VAD->NoiseLevelBias[ k ] );
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silk_assert( nrg > 0 );
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/* Invert energies */
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inv_nrg = silk_DIV32( silk_int32_MAX, nrg );
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silk_assert( inv_nrg >= 0 );
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/* Less update when subband energy is high */
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if( nrg > silk_LSHIFT( nl, 3 ) ) {
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coef = VAD_NOISE_LEVEL_SMOOTH_COEF_Q16 >> 3;
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} else if( nrg < nl ) {
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coef = VAD_NOISE_LEVEL_SMOOTH_COEF_Q16;
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} else {
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coef = silk_SMULWB( silk_SMULWW( inv_nrg, nl ), VAD_NOISE_LEVEL_SMOOTH_COEF_Q16 << 1 );
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}
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/* Initially faster smoothing */
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coef = silk_max_int( coef, min_coef );
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|
/* Smooth inverse energies */
|
||
|
|
psSilk_VAD->inv_NL[ k ] = silk_SMLAWB( psSilk_VAD->inv_NL[ k ], inv_nrg - psSilk_VAD->inv_NL[ k ], coef );
|
||
|
|
silk_assert( psSilk_VAD->inv_NL[ k ] >= 0 );
|
||
|
|
|
||
|
|
/* Compute noise level by inverting again */
|
||
|
|
nl = silk_DIV32( silk_int32_MAX, psSilk_VAD->inv_NL[ k ] );
|
||
|
|
silk_assert( nl >= 0 );
|
||
|
|
|
||
|
|
/* Limit noise levels (guarantee 7 bits of head room) */
|
||
|
|
nl = silk_min( nl, 0x00FFFFFF );
|
||
|
|
|
||
|
|
/* Store as part of state */
|
||
|
|
psSilk_VAD->NL[ k ] = nl;
|
||
|
|
}
|
||
|
|
|
||
|
|
/* Increment frame counter */
|
||
|
|
psSilk_VAD->counter++;
|
||
|
|
}
|