michael@0: /*********************************************************************** michael@0: Copyright (c) 2006-2011, Skype Limited. All rights reserved. michael@0: Redistribution and use in source and binary forms, with or without michael@0: modification, are permitted provided that the following conditions michael@0: are met: michael@0: - Redistributions of source code must retain the above copyright notice, michael@0: this list of conditions and the following disclaimer. michael@0: - Redistributions in binary form must reproduce the above copyright michael@0: notice, this list of conditions and the following disclaimer in the michael@0: documentation and/or other materials provided with the distribution. michael@0: - Neither the name of Internet Society, IETF or IETF Trust, nor the michael@0: names of specific contributors, may be used to endorse or promote michael@0: products derived from this software without specific prior written michael@0: permission. michael@0: THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" michael@0: AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE michael@0: IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE michael@0: ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE michael@0: LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR michael@0: CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF michael@0: SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS michael@0: INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN michael@0: CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) michael@0: ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE michael@0: POSSIBILITY OF SUCH DAMAGE. michael@0: ***********************************************************************/ michael@0: michael@0: #ifdef HAVE_CONFIG_H michael@0: #include "config.h" michael@0: #endif michael@0: michael@0: #include "define.h" michael@0: #include "main_FLP.h" michael@0: #include "tuning_parameters.h" michael@0: michael@0: /* LPC analysis */ michael@0: void silk_find_LPC_FLP( michael@0: silk_encoder_state *psEncC, /* I/O Encoder state */ michael@0: opus_int16 NLSF_Q15[], /* O NLSFs */ michael@0: const silk_float x[], /* I Input signal */ michael@0: const silk_float minInvGain /* I Inverse of max prediction gain */ michael@0: ) michael@0: { michael@0: opus_int k, subfr_length; michael@0: silk_float a[ MAX_LPC_ORDER ]; michael@0: michael@0: /* Used only for NLSF interpolation */ michael@0: silk_float res_nrg, res_nrg_2nd, res_nrg_interp; michael@0: opus_int16 NLSF0_Q15[ MAX_LPC_ORDER ]; michael@0: silk_float a_tmp[ MAX_LPC_ORDER ]; michael@0: silk_float LPC_res[ MAX_FRAME_LENGTH + MAX_NB_SUBFR * MAX_LPC_ORDER ]; michael@0: michael@0: subfr_length = psEncC->subfr_length + psEncC->predictLPCOrder; michael@0: michael@0: /* Default: No interpolation */ michael@0: psEncC->indices.NLSFInterpCoef_Q2 = 4; michael@0: michael@0: /* Burg AR analysis for the full frame */ michael@0: res_nrg = silk_burg_modified_FLP( a, x, minInvGain, subfr_length, psEncC->nb_subfr, psEncC->predictLPCOrder ); michael@0: michael@0: if( psEncC->useInterpolatedNLSFs && !psEncC->first_frame_after_reset && psEncC->nb_subfr == MAX_NB_SUBFR ) { michael@0: /* Optimal solution for last 10 ms; subtract residual energy here, as that's easier than */ michael@0: /* adding it to the residual energy of the first 10 ms in each iteration of the search below */ michael@0: res_nrg -= silk_burg_modified_FLP( a_tmp, x + ( MAX_NB_SUBFR / 2 ) * subfr_length, minInvGain, subfr_length, MAX_NB_SUBFR / 2, psEncC->predictLPCOrder ); michael@0: michael@0: /* Convert to NLSFs */ michael@0: silk_A2NLSF_FLP( NLSF_Q15, a_tmp, psEncC->predictLPCOrder ); michael@0: michael@0: /* Search over interpolation indices to find the one with lowest residual energy */ michael@0: res_nrg_2nd = silk_float_MAX; michael@0: for( k = 3; k >= 0; k-- ) { michael@0: /* Interpolate NLSFs for first half */ michael@0: silk_interpolate( NLSF0_Q15, psEncC->prev_NLSFq_Q15, NLSF_Q15, k, psEncC->predictLPCOrder ); michael@0: michael@0: /* Convert to LPC for residual energy evaluation */ michael@0: silk_NLSF2A_FLP( a_tmp, NLSF0_Q15, psEncC->predictLPCOrder ); michael@0: michael@0: /* Calculate residual energy with LSF interpolation */ michael@0: silk_LPC_analysis_filter_FLP( LPC_res, a_tmp, x, 2 * subfr_length, psEncC->predictLPCOrder ); michael@0: res_nrg_interp = (silk_float)( michael@0: silk_energy_FLP( LPC_res + psEncC->predictLPCOrder, subfr_length - psEncC->predictLPCOrder ) + michael@0: silk_energy_FLP( LPC_res + psEncC->predictLPCOrder + subfr_length, subfr_length - psEncC->predictLPCOrder ) ); michael@0: michael@0: /* Determine whether current interpolated NLSFs are best so far */ michael@0: if( res_nrg_interp < res_nrg ) { michael@0: /* Interpolation has lower residual energy */ michael@0: res_nrg = res_nrg_interp; michael@0: psEncC->indices.NLSFInterpCoef_Q2 = (opus_int8)k; michael@0: } else if( res_nrg_interp > res_nrg_2nd ) { michael@0: /* No reason to continue iterating - residual energies will continue to climb */ michael@0: break; michael@0: } michael@0: res_nrg_2nd = res_nrg_interp; michael@0: } michael@0: } michael@0: michael@0: if( psEncC->indices.NLSFInterpCoef_Q2 == 4 ) { michael@0: /* NLSF interpolation is currently inactive, calculate NLSFs from full frame AR coefficients */ michael@0: silk_A2NLSF_FLP( NLSF_Q15, a, psEncC->predictLPCOrder ); michael@0: } michael@0: michael@0: silk_assert( psEncC->indices.NLSFInterpCoef_Q2 == 4 || michael@0: ( psEncC->useInterpolatedNLSFs && !psEncC->first_frame_after_reset && psEncC->nb_subfr == MAX_NB_SUBFR ) ); michael@0: }