125 lines
6.5 KiB
C
125 lines
6.5 KiB
C
/***********************************************************************
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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, (subject to the limitations in the disclaimer below)
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are permitted provided that the following conditions 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 Skype Limited, nor the names of specific
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contributors, may be used to endorse or promote products derived from
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this software without specific prior written permission.
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NO EXPRESS OR IMPLIED LICENSES TO ANY PARTY'S PATENT RIGHTS ARE GRANTED
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BY THIS LICENSE. THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
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CONTRIBUTORS ''AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING,
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BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
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FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
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COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
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INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
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USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
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ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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OF THIS SOFTWARE, EVEN IF ADVISED OF THE 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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#ifdef FIXED_POINT
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#include "silk_main_FIX.h"
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#else
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#include "silk_main_FLP.h"
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#endif
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#include "silk_tuning_parameters.h"
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/* High-pass filter with cutoff frequency adaptation based on pitch lag statistics */
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void silk_HP_variable_cutoff(
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silk_encoder_state_Fxx state_Fxx[], /* I/O Encoder states */
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const SKP_int nChannels /* I Number of channels */
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)
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{
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SKP_int quality_Q15, cutoff_Hz;
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SKP_int32 B_Q28[ 3 ], A_Q28[ 2 ];
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SKP_int32 Fc_Q19, r_Q28, r_Q22;
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SKP_int32 pitch_freq_Hz_Q16, pitch_freq_log_Q7, delta_freq_Q7;
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silk_encoder_state *psEncC1 = &state_Fxx[ 0 ].sCmn;
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if( psEncC1->HP_cutoff_Hz == 0 ) {
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/* Adaptive cutoff frequency: estimate low end of pitch frequency range */
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if( psEncC1->prevSignalType == TYPE_VOICED ) {
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/* difference, in log domain */
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pitch_freq_Hz_Q16 = SKP_DIV32_16( SKP_LSHIFT( SKP_MUL( psEncC1->fs_kHz, 1000 ), 16 ), psEncC1->prevLag );
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pitch_freq_log_Q7 = silk_lin2log( pitch_freq_Hz_Q16 ) - ( 16 << 7 );
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/* adjustment based on quality */
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quality_Q15 = psEncC1->input_quality_bands_Q15[ 0 ];
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pitch_freq_log_Q7 = SKP_SMLAWB( pitch_freq_log_Q7, SKP_SMULWB( SKP_LSHIFT( -quality_Q15, 2 ), quality_Q15 ),
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pitch_freq_log_Q7 - ( silk_lin2log( SILK_FIX_CONST( VARIABLE_HP_MIN_CUTOFF_HZ, 16 ) ) - ( 16 << 7 ) ) );
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/* delta_freq = pitch_freq_log - psEnc->variable_HP_smth1; */
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delta_freq_Q7 = pitch_freq_log_Q7 - SKP_RSHIFT( psEncC1->variable_HP_smth1_Q15, 8 );
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if( delta_freq_Q7 < 0 ) {
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/* less smoothing for decreasing pitch frequency, to track something close to the minimum */
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delta_freq_Q7 = SKP_MUL( delta_freq_Q7, 3 );
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}
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/* limit delta, to reduce impact of outliers in pitch estimation */
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delta_freq_Q7 = SKP_LIMIT_32( delta_freq_Q7, -SILK_FIX_CONST( VARIABLE_HP_MAX_DELTA_FREQ, 7 ), SILK_FIX_CONST( VARIABLE_HP_MAX_DELTA_FREQ, 7 ) );
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/* update smoother */
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psEncC1->variable_HP_smth1_Q15 = SKP_SMLAWB( psEncC1->variable_HP_smth1_Q15,
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SKP_SMULBB( psEncC1->speech_activity_Q8, delta_freq_Q7 ), SILK_FIX_CONST( VARIABLE_HP_SMTH_COEF1, 16 ) );
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/* limit frequency range */
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psEncC1->variable_HP_smth1_Q15 = SKP_LIMIT_32( psEncC1->variable_HP_smth1_Q15,
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SKP_LSHIFT( silk_lin2log( VARIABLE_HP_MIN_CUTOFF_HZ ), 8 ),
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SKP_LSHIFT( silk_lin2log( VARIABLE_HP_MAX_CUTOFF_HZ ), 8 ) );
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}
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} else {
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/* Externally-controlled cutoff frequency */
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cutoff_Hz = SKP_LIMIT( psEncC1->HP_cutoff_Hz, 10, 500 );
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psEncC1->variable_HP_smth1_Q15 = SKP_LSHIFT( silk_lin2log( cutoff_Hz ), 8 );
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}
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/* second smoother */
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psEncC1->variable_HP_smth2_Q15 = SKP_SMLAWB( psEncC1->variable_HP_smth2_Q15,
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psEncC1->variable_HP_smth1_Q15 - psEncC1->variable_HP_smth2_Q15, SILK_FIX_CONST( VARIABLE_HP_SMTH_COEF2, 16 ) );
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/* convert from log scale to Hertz */
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cutoff_Hz = silk_log2lin( SKP_RSHIFT( psEncC1->variable_HP_smth2_Q15, 8 ) );
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/********************************/
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/* Compute Filter Coefficients */
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/********************************/
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/* compute cut-off frequency, in radians */
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/* Fc_num = 1.5 * 3.14159 * cutoff_Hz */
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/* Fc_denom = 1e3f * psEncC1->fs_kHz */
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SKP_assert( cutoff_Hz <= SKP_int32_MAX / SILK_FIX_CONST( 1.5 * 3.14159 / 1000, 19 ) );
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Fc_Q19 = SKP_DIV32_16( SKP_SMULBB( SILK_FIX_CONST( 1.5 * 3.14159 / 1000, 19 ), cutoff_Hz ), psEncC1->fs_kHz );
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SKP_assert( Fc_Q19 > 0 && Fc_Q19 < 32768 );
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r_Q28 = SILK_FIX_CONST( 1.0, 28 ) - SKP_MUL( SILK_FIX_CONST( 0.92, 9 ), Fc_Q19 );
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/* b = r * [ 1; -2; 1 ]; */
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/* a = [ 1; -2 * r * ( 1 - 0.5 * Fc^2 ); r^2 ]; */
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B_Q28[ 0 ] = r_Q28;
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B_Q28[ 1 ] = SKP_LSHIFT( -r_Q28, 1 );
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B_Q28[ 2 ] = r_Q28;
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/* -r * ( 2 - Fc * Fc ); */
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r_Q22 = SKP_RSHIFT( r_Q28, 6 );
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A_Q28[ 0 ] = SKP_SMULWW( r_Q22, SKP_SMULWW( Fc_Q19, Fc_Q19 ) - SILK_FIX_CONST( 2.0, 22 ) );
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A_Q28[ 1 ] = SKP_SMULWW( r_Q22, r_Q22 );
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/********************************/
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/* High-Pass Filter */
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/********************************/
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silk_biquad_alt( psEncC1->inputBuf, B_Q28, A_Q28, psEncC1->In_HP_State, psEncC1->inputBuf, psEncC1->frame_length );
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if( nChannels == 2 ) {
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silk_biquad_alt( state_Fxx[ 1 ].sCmn.inputBuf, B_Q28, A_Q28, state_Fxx[ 1 ].sCmn.In_HP_State,
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state_Fxx[ 1 ].sCmn.inputBuf, state_Fxx[ 1 ].sCmn.frame_length );
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}
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}
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