1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/media/libopus/silk/float/find_LPC_FLP.c Wed Dec 31 06:09:35 2014 +0100
1.3 @@ -0,0 +1,104 @@
1.4 +/***********************************************************************
1.5 +Copyright (c) 2006-2011, Skype Limited. All rights reserved.
1.6 +Redistribution and use in source and binary forms, with or without
1.7 +modification, are permitted provided that the following conditions
1.8 +are met:
1.9 +- Redistributions of source code must retain the above copyright notice,
1.10 +this list of conditions and the following disclaimer.
1.11 +- Redistributions in binary form must reproduce the above copyright
1.12 +notice, this list of conditions and the following disclaimer in the
1.13 +documentation and/or other materials provided with the distribution.
1.14 +- Neither the name of Internet Society, IETF or IETF Trust, nor the
1.15 +names of specific contributors, may be used to endorse or promote
1.16 +products derived from this software without specific prior written
1.17 +permission.
1.18 +THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
1.19 +AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
1.20 +IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
1.21 +ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
1.22 +LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
1.23 +CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
1.24 +SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
1.25 +INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
1.26 +CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
1.27 +ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
1.28 +POSSIBILITY OF SUCH DAMAGE.
1.29 +***********************************************************************/
1.30 +
1.31 +#ifdef HAVE_CONFIG_H
1.32 +#include "config.h"
1.33 +#endif
1.34 +
1.35 +#include "define.h"
1.36 +#include "main_FLP.h"
1.37 +#include "tuning_parameters.h"
1.38 +
1.39 +/* LPC analysis */
1.40 +void silk_find_LPC_FLP(
1.41 + silk_encoder_state *psEncC, /* I/O Encoder state */
1.42 + opus_int16 NLSF_Q15[], /* O NLSFs */
1.43 + const silk_float x[], /* I Input signal */
1.44 + const silk_float minInvGain /* I Inverse of max prediction gain */
1.45 +)
1.46 +{
1.47 + opus_int k, subfr_length;
1.48 + silk_float a[ MAX_LPC_ORDER ];
1.49 +
1.50 + /* Used only for NLSF interpolation */
1.51 + silk_float res_nrg, res_nrg_2nd, res_nrg_interp;
1.52 + opus_int16 NLSF0_Q15[ MAX_LPC_ORDER ];
1.53 + silk_float a_tmp[ MAX_LPC_ORDER ];
1.54 + silk_float LPC_res[ MAX_FRAME_LENGTH + MAX_NB_SUBFR * MAX_LPC_ORDER ];
1.55 +
1.56 + subfr_length = psEncC->subfr_length + psEncC->predictLPCOrder;
1.57 +
1.58 + /* Default: No interpolation */
1.59 + psEncC->indices.NLSFInterpCoef_Q2 = 4;
1.60 +
1.61 + /* Burg AR analysis for the full frame */
1.62 + res_nrg = silk_burg_modified_FLP( a, x, minInvGain, subfr_length, psEncC->nb_subfr, psEncC->predictLPCOrder );
1.63 +
1.64 + if( psEncC->useInterpolatedNLSFs && !psEncC->first_frame_after_reset && psEncC->nb_subfr == MAX_NB_SUBFR ) {
1.65 + /* Optimal solution for last 10 ms; subtract residual energy here, as that's easier than */
1.66 + /* adding it to the residual energy of the first 10 ms in each iteration of the search below */
1.67 + res_nrg -= silk_burg_modified_FLP( a_tmp, x + ( MAX_NB_SUBFR / 2 ) * subfr_length, minInvGain, subfr_length, MAX_NB_SUBFR / 2, psEncC->predictLPCOrder );
1.68 +
1.69 + /* Convert to NLSFs */
1.70 + silk_A2NLSF_FLP( NLSF_Q15, a_tmp, psEncC->predictLPCOrder );
1.71 +
1.72 + /* Search over interpolation indices to find the one with lowest residual energy */
1.73 + res_nrg_2nd = silk_float_MAX;
1.74 + for( k = 3; k >= 0; k-- ) {
1.75 + /* Interpolate NLSFs for first half */
1.76 + silk_interpolate( NLSF0_Q15, psEncC->prev_NLSFq_Q15, NLSF_Q15, k, psEncC->predictLPCOrder );
1.77 +
1.78 + /* Convert to LPC for residual energy evaluation */
1.79 + silk_NLSF2A_FLP( a_tmp, NLSF0_Q15, psEncC->predictLPCOrder );
1.80 +
1.81 + /* Calculate residual energy with LSF interpolation */
1.82 + silk_LPC_analysis_filter_FLP( LPC_res, a_tmp, x, 2 * subfr_length, psEncC->predictLPCOrder );
1.83 + res_nrg_interp = (silk_float)(
1.84 + silk_energy_FLP( LPC_res + psEncC->predictLPCOrder, subfr_length - psEncC->predictLPCOrder ) +
1.85 + silk_energy_FLP( LPC_res + psEncC->predictLPCOrder + subfr_length, subfr_length - psEncC->predictLPCOrder ) );
1.86 +
1.87 + /* Determine whether current interpolated NLSFs are best so far */
1.88 + if( res_nrg_interp < res_nrg ) {
1.89 + /* Interpolation has lower residual energy */
1.90 + res_nrg = res_nrg_interp;
1.91 + psEncC->indices.NLSFInterpCoef_Q2 = (opus_int8)k;
1.92 + } else if( res_nrg_interp > res_nrg_2nd ) {
1.93 + /* No reason to continue iterating - residual energies will continue to climb */
1.94 + break;
1.95 + }
1.96 + res_nrg_2nd = res_nrg_interp;
1.97 + }
1.98 + }
1.99 +
1.100 + if( psEncC->indices.NLSFInterpCoef_Q2 == 4 ) {
1.101 + /* NLSF interpolation is currently inactive, calculate NLSFs from full frame AR coefficients */
1.102 + silk_A2NLSF_FLP( NLSF_Q15, a, psEncC->predictLPCOrder );
1.103 + }
1.104 +
1.105 + silk_assert( psEncC->indices.NLSFInterpCoef_Q2 == 4 ||
1.106 + ( psEncC->useInterpolatedNLSFs && !psEncC->first_frame_after_reset && psEncC->nb_subfr == MAX_NB_SUBFR ) );
1.107 +}
