cannam@154: /*********************************************************************** cannam@154: Copyright (c) 2006-2011, Skype Limited. All rights reserved. cannam@154: Redistribution and use in source and binary forms, with or without cannam@154: modification, are permitted provided that the following conditions cannam@154: are met: cannam@154: - Redistributions of source code must retain the above copyright notice, cannam@154: this list of conditions and the following disclaimer. cannam@154: - Redistributions in binary form must reproduce the above copyright cannam@154: notice, this list of conditions and the following disclaimer in the cannam@154: documentation and/or other materials provided with the distribution. cannam@154: - Neither the name of Internet Society, IETF or IETF Trust, nor the cannam@154: names of specific contributors, may be used to endorse or promote cannam@154: products derived from this software without specific prior written cannam@154: permission. cannam@154: THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" cannam@154: AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE cannam@154: IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE cannam@154: ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE cannam@154: LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR cannam@154: CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF cannam@154: SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS cannam@154: INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN cannam@154: CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) cannam@154: ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE cannam@154: POSSIBILITY OF SUCH DAMAGE. cannam@154: ***********************************************************************/ cannam@154: cannam@154: #ifdef HAVE_CONFIG_H cannam@154: #include "config.h" cannam@154: #endif cannam@154: cannam@154: #include "define.h" cannam@154: #include "main_FLP.h" cannam@154: #include "tuning_parameters.h" cannam@154: cannam@154: /* LPC analysis */ cannam@154: void silk_find_LPC_FLP( cannam@154: silk_encoder_state *psEncC, /* I/O Encoder state */ cannam@154: opus_int16 NLSF_Q15[], /* O NLSFs */ cannam@154: const silk_float x[], /* I Input signal */ cannam@154: const silk_float minInvGain /* I Inverse of max prediction gain */ cannam@154: ) cannam@154: { cannam@154: opus_int k, subfr_length; cannam@154: silk_float a[ MAX_LPC_ORDER ]; cannam@154: cannam@154: /* Used only for NLSF interpolation */ cannam@154: silk_float res_nrg, res_nrg_2nd, res_nrg_interp; cannam@154: opus_int16 NLSF0_Q15[ MAX_LPC_ORDER ]; cannam@154: silk_float a_tmp[ MAX_LPC_ORDER ]; cannam@154: silk_float LPC_res[ MAX_FRAME_LENGTH + MAX_NB_SUBFR * MAX_LPC_ORDER ]; cannam@154: cannam@154: subfr_length = psEncC->subfr_length + psEncC->predictLPCOrder; cannam@154: cannam@154: /* Default: No interpolation */ cannam@154: psEncC->indices.NLSFInterpCoef_Q2 = 4; cannam@154: cannam@154: /* Burg AR analysis for the full frame */ cannam@154: res_nrg = silk_burg_modified_FLP( a, x, minInvGain, subfr_length, psEncC->nb_subfr, psEncC->predictLPCOrder ); cannam@154: cannam@154: if( psEncC->useInterpolatedNLSFs && !psEncC->first_frame_after_reset && psEncC->nb_subfr == MAX_NB_SUBFR ) { cannam@154: /* Optimal solution for last 10 ms; subtract residual energy here, as that's easier than */ cannam@154: /* adding it to the residual energy of the first 10 ms in each iteration of the search below */ cannam@154: res_nrg -= silk_burg_modified_FLP( a_tmp, x + ( MAX_NB_SUBFR / 2 ) * subfr_length, minInvGain, subfr_length, MAX_NB_SUBFR / 2, psEncC->predictLPCOrder ); cannam@154: cannam@154: /* Convert to NLSFs */ cannam@154: silk_A2NLSF_FLP( NLSF_Q15, a_tmp, psEncC->predictLPCOrder ); cannam@154: cannam@154: /* Search over interpolation indices to find the one with lowest residual energy */ cannam@154: res_nrg_2nd = silk_float_MAX; cannam@154: for( k = 3; k >= 0; k-- ) { cannam@154: /* Interpolate NLSFs for first half */ cannam@154: silk_interpolate( NLSF0_Q15, psEncC->prev_NLSFq_Q15, NLSF_Q15, k, psEncC->predictLPCOrder ); cannam@154: cannam@154: /* Convert to LPC for residual energy evaluation */ cannam@154: silk_NLSF2A_FLP( a_tmp, NLSF0_Q15, psEncC->predictLPCOrder, psEncC->arch ); cannam@154: cannam@154: /* Calculate residual energy with LSF interpolation */ cannam@154: silk_LPC_analysis_filter_FLP( LPC_res, a_tmp, x, 2 * subfr_length, psEncC->predictLPCOrder ); cannam@154: res_nrg_interp = (silk_float)( cannam@154: silk_energy_FLP( LPC_res + psEncC->predictLPCOrder, subfr_length - psEncC->predictLPCOrder ) + cannam@154: silk_energy_FLP( LPC_res + psEncC->predictLPCOrder + subfr_length, subfr_length - psEncC->predictLPCOrder ) ); cannam@154: cannam@154: /* Determine whether current interpolated NLSFs are best so far */ cannam@154: if( res_nrg_interp < res_nrg ) { cannam@154: /* Interpolation has lower residual energy */ cannam@154: res_nrg = res_nrg_interp; cannam@154: psEncC->indices.NLSFInterpCoef_Q2 = (opus_int8)k; cannam@154: } else if( res_nrg_interp > res_nrg_2nd ) { cannam@154: /* No reason to continue iterating - residual energies will continue to climb */ cannam@154: break; cannam@154: } cannam@154: res_nrg_2nd = res_nrg_interp; cannam@154: } cannam@154: } cannam@154: cannam@154: if( psEncC->indices.NLSFInterpCoef_Q2 == 4 ) { cannam@154: /* NLSF interpolation is currently inactive, calculate NLSFs from full frame AR coefficients */ cannam@154: silk_A2NLSF_FLP( NLSF_Q15, a, psEncC->predictLPCOrder ); cannam@154: } cannam@154: cannam@154: celt_assert( psEncC->indices.NLSFInterpCoef_Q2 == 4 || cannam@154: ( psEncC->useInterpolatedNLSFs && !psEncC->first_frame_after_reset && psEncC->nb_subfr == MAX_NB_SUBFR ) ); cannam@154: }