151 lines
7.2 KiB
C
151 lines
7.2 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, 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_FIX.h"
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#include "stack_alloc.h"
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#include "tuning_parameters.h"
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/* Finds LPC vector from correlations, and converts to NLSF */
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void silk_find_LPC_FIX(
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silk_encoder_state *psEncC, /* I/O Encoder state */
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opus_int16 NLSF_Q15[], /* O NLSFs */
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const opus_int16 x[], /* I Input signal */
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const opus_int32 minInvGain_Q30 /* I Inverse of max prediction gain */
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)
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{
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opus_int k, subfr_length;
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opus_int32 a_Q16[ MAX_LPC_ORDER ];
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opus_int isInterpLower, shift;
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opus_int32 res_nrg0, res_nrg1;
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opus_int rshift0, rshift1;
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/* Used only for LSF interpolation */
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opus_int32 a_tmp_Q16[ MAX_LPC_ORDER ], res_nrg_interp, res_nrg, res_tmp_nrg;
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opus_int res_nrg_interp_Q, res_nrg_Q, res_tmp_nrg_Q;
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opus_int16 a_tmp_Q12[ MAX_LPC_ORDER ];
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opus_int16 NLSF0_Q15[ MAX_LPC_ORDER ];
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SAVE_STACK;
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subfr_length = psEncC->subfr_length + psEncC->predictLPCOrder;
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/* Default: no interpolation */
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psEncC->indices.NLSFInterpCoef_Q2 = 4;
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/* Burg AR analysis for the full frame */
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silk_burg_modified( &res_nrg, &res_nrg_Q, a_Q16, x, minInvGain_Q30, subfr_length, psEncC->nb_subfr, psEncC->predictLPCOrder, psEncC->arch );
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if( psEncC->useInterpolatedNLSFs && !psEncC->first_frame_after_reset && psEncC->nb_subfr == MAX_NB_SUBFR ) {
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VARDECL( opus_int16, LPC_res );
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/* Optimal solution for last 10 ms */
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silk_burg_modified( &res_tmp_nrg, &res_tmp_nrg_Q, a_tmp_Q16, x + 2 * subfr_length, minInvGain_Q30, subfr_length, 2, psEncC->predictLPCOrder, psEncC->arch );
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/* subtract residual energy here, as that's easier than adding it to the */
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/* residual energy of the first 10 ms in each iteration of the search below */
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shift = res_tmp_nrg_Q - res_nrg_Q;
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if( shift >= 0 ) {
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if( shift < 32 ) {
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res_nrg = res_nrg - silk_RSHIFT( res_tmp_nrg, shift );
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}
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} else {
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silk_assert( shift > -32 );
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res_nrg = silk_RSHIFT( res_nrg, -shift ) - res_tmp_nrg;
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res_nrg_Q = res_tmp_nrg_Q;
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}
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/* Convert to NLSFs */
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silk_A2NLSF( NLSF_Q15, a_tmp_Q16, psEncC->predictLPCOrder );
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ALLOC( LPC_res, 2 * subfr_length, opus_int16 );
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/* Search over interpolation indices to find the one with lowest residual energy */
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for( k = 3; k >= 0; k-- ) {
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/* Interpolate NLSFs for first half */
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silk_interpolate( NLSF0_Q15, psEncC->prev_NLSFq_Q15, NLSF_Q15, k, psEncC->predictLPCOrder );
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/* Convert to LPC for residual energy evaluation */
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silk_NLSF2A( a_tmp_Q12, NLSF0_Q15, psEncC->predictLPCOrder, psEncC->arch );
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/* Calculate residual energy with NLSF interpolation */
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silk_LPC_analysis_filter( LPC_res, x, a_tmp_Q12, 2 * subfr_length, psEncC->predictLPCOrder, psEncC->arch );
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silk_sum_sqr_shift( &res_nrg0, &rshift0, LPC_res + psEncC->predictLPCOrder, subfr_length - psEncC->predictLPCOrder );
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silk_sum_sqr_shift( &res_nrg1, &rshift1, LPC_res + psEncC->predictLPCOrder + subfr_length, subfr_length - psEncC->predictLPCOrder );
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/* Add subframe energies from first half frame */
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shift = rshift0 - rshift1;
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if( shift >= 0 ) {
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res_nrg1 = silk_RSHIFT( res_nrg1, shift );
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res_nrg_interp_Q = -rshift0;
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} else {
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res_nrg0 = silk_RSHIFT( res_nrg0, -shift );
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res_nrg_interp_Q = -rshift1;
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}
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res_nrg_interp = silk_ADD32( res_nrg0, res_nrg1 );
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/* Compare with first half energy without NLSF interpolation, or best interpolated value so far */
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shift = res_nrg_interp_Q - res_nrg_Q;
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if( shift >= 0 ) {
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if( silk_RSHIFT( res_nrg_interp, shift ) < res_nrg ) {
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isInterpLower = silk_TRUE;
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} else {
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isInterpLower = silk_FALSE;
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}
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} else {
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if( -shift < 32 ) {
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if( res_nrg_interp < silk_RSHIFT( res_nrg, -shift ) ) {
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isInterpLower = silk_TRUE;
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} else {
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isInterpLower = silk_FALSE;
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}
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} else {
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isInterpLower = silk_FALSE;
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}
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}
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/* Determine whether current interpolated NLSFs are best so far */
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if( isInterpLower == silk_TRUE ) {
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/* Interpolation has lower residual energy */
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res_nrg = res_nrg_interp;
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res_nrg_Q = res_nrg_interp_Q;
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psEncC->indices.NLSFInterpCoef_Q2 = (opus_int8)k;
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}
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}
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}
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if( psEncC->indices.NLSFInterpCoef_Q2 == 4 ) {
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/* NLSF interpolation is currently inactive, calculate NLSFs from full frame AR coefficients */
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silk_A2NLSF( NLSF_Q15, a_Q16, psEncC->predictLPCOrder );
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}
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celt_assert( psEncC->indices.NLSFInterpCoef_Q2 == 4 || ( psEncC->useInterpolatedNLSFs && !psEncC->first_frame_after_reset && psEncC->nb_subfr == MAX_NB_SUBFR ) );
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RESTORE_STACK;
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}
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