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diff --git a/media/libopus/silk/float/find_LPC_FLP.c b/media/libopus/silk/float/find_LPC_FLP.c
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+/***********************************************************************
+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 "define.h"
+#include "main_FLP.h"
+#include "tuning_parameters.h"
+
+/* LPC analysis */
+void silk_find_LPC_FLP(
+ silk_encoder_state *psEncC, /* I/O Encoder state */
+ opus_int16 NLSF_Q15[], /* O NLSFs */
+ const silk_float x[], /* I Input signal */
+ const silk_float minInvGain /* I Inverse of max prediction gain */
+)
+{
+ opus_int k, subfr_length;
+ silk_float a[ MAX_LPC_ORDER ];
+
+ /* Used only for NLSF interpolation */
+ silk_float res_nrg, res_nrg_2nd, res_nrg_interp;
+ opus_int16 NLSF0_Q15[ MAX_LPC_ORDER ];
+ silk_float a_tmp[ MAX_LPC_ORDER ];
+ silk_float LPC_res[ MAX_FRAME_LENGTH + MAX_NB_SUBFR * MAX_LPC_ORDER ];
+
+ subfr_length = psEncC->subfr_length + psEncC->predictLPCOrder;
+
+ /* Default: No interpolation */
+ psEncC->indices.NLSFInterpCoef_Q2 = 4;
+
+ /* Burg AR analysis for the full frame */
+ res_nrg = silk_burg_modified_FLP( a, x, minInvGain, subfr_length, psEncC->nb_subfr, psEncC->predictLPCOrder );
+
+ if( psEncC->useInterpolatedNLSFs && !psEncC->first_frame_after_reset && psEncC->nb_subfr == MAX_NB_SUBFR ) {
+ /* Optimal solution for last 10 ms; subtract residual energy here, as that's easier than */
+ /* adding it to the residual energy of the first 10 ms in each iteration of the search below */
+ res_nrg -= silk_burg_modified_FLP( a_tmp, x + ( MAX_NB_SUBFR / 2 ) * subfr_length, minInvGain, subfr_length, MAX_NB_SUBFR / 2, psEncC->predictLPCOrder );
+
+ /* Convert to NLSFs */
+ silk_A2NLSF_FLP( NLSF_Q15, a_tmp, psEncC->predictLPCOrder );
+
+ /* Search over interpolation indices to find the one with lowest residual energy */
+ res_nrg_2nd = silk_float_MAX;
+ for( k = 3; k >= 0; k-- ) {
+ /* Interpolate NLSFs for first half */
+ silk_interpolate( NLSF0_Q15, psEncC->prev_NLSFq_Q15, NLSF_Q15, k, psEncC->predictLPCOrder );
+
+ /* Convert to LPC for residual energy evaluation */
+ silk_NLSF2A_FLP( a_tmp, NLSF0_Q15, psEncC->predictLPCOrder );
+
+ /* Calculate residual energy with LSF interpolation */
+ silk_LPC_analysis_filter_FLP( LPC_res, a_tmp, x, 2 * subfr_length, psEncC->predictLPCOrder );
+ res_nrg_interp = (silk_float)(
+ silk_energy_FLP( LPC_res + psEncC->predictLPCOrder, subfr_length - psEncC->predictLPCOrder ) +
+ silk_energy_FLP( LPC_res + psEncC->predictLPCOrder + subfr_length, subfr_length - psEncC->predictLPCOrder ) );
+
+ /* Determine whether current interpolated NLSFs are best so far */
+ if( res_nrg_interp < res_nrg ) {
+ /* Interpolation has lower residual energy */
+ res_nrg = res_nrg_interp;
+ psEncC->indices.NLSFInterpCoef_Q2 = (opus_int8)k;
+ } else if( res_nrg_interp > res_nrg_2nd ) {
+ /* No reason to continue iterating - residual energies will continue to climb */
+ break;
+ }
+ res_nrg_2nd = res_nrg_interp;
+ }
+ }
+
+ if( psEncC->indices.NLSFInterpCoef_Q2 == 4 ) {
+ /* NLSF interpolation is currently inactive, calculate NLSFs from full frame AR coefficients */
+ silk_A2NLSF_FLP( NLSF_Q15, a, psEncC->predictLPCOrder );
+ }
+
+ silk_assert( psEncC->indices.NLSFInterpCoef_Q2 == 4 ||
+ ( psEncC->useInterpolatedNLSFs && !psEncC->first_frame_after_reset && psEncC->nb_subfr == MAX_NB_SUBFR ) );
+}