Alexandre Lision | 744f742 | 2013-09-25 11:39:37 -0400 | [diff] [blame^] | 1 | /*********************************************************************** |
| 2 | Copyright (c) 2006-2011, Skype Limited. All rights reserved. |
| 3 | Redistribution and use in source and binary forms, with or without |
| 4 | modification, are permitted provided that the following conditions |
| 5 | are met: |
| 6 | - Redistributions of source code must retain the above copyright notice, |
| 7 | this list of conditions and the following disclaimer. |
| 8 | - Redistributions in binary form must reproduce the above copyright |
| 9 | notice, this list of conditions and the following disclaimer in the |
| 10 | documentation and/or other materials provided with the distribution. |
| 11 | - Neither the name of Internet Society, IETF or IETF Trust, nor the |
| 12 | names of specific contributors, may be used to endorse or promote |
| 13 | products derived from this software without specific prior written |
| 14 | permission. |
| 15 | THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS “AS IS” |
| 16 | AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
| 17 | IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
| 18 | ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE |
| 19 | LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR |
| 20 | CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF |
| 21 | SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS |
| 22 | INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN |
| 23 | CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) |
| 24 | ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE |
| 25 | POSSIBILITY OF SUCH DAMAGE. |
| 26 | ***********************************************************************/ |
| 27 | |
| 28 | #ifdef HAVE_CONFIG_H |
| 29 | #include "config.h" |
| 30 | #endif |
| 31 | |
| 32 | #include "define.h" |
| 33 | #include "main_FLP.h" |
| 34 | #include "tuning_parameters.h" |
| 35 | |
| 36 | /* LPC analysis */ |
| 37 | void silk_find_LPC_FLP( |
| 38 | silk_encoder_state *psEncC, /* I/O Encoder state */ |
| 39 | opus_int16 NLSF_Q15[], /* O NLSFs */ |
| 40 | const silk_float x[], /* I Input signal */ |
| 41 | const silk_float minInvGain /* I Inverse of max prediction gain */ |
| 42 | ) |
| 43 | { |
| 44 | opus_int k, subfr_length; |
| 45 | silk_float a[ MAX_LPC_ORDER ]; |
| 46 | |
| 47 | /* Used only for NLSF interpolation */ |
| 48 | silk_float res_nrg, res_nrg_2nd, res_nrg_interp; |
| 49 | opus_int16 NLSF0_Q15[ MAX_LPC_ORDER ]; |
| 50 | silk_float a_tmp[ MAX_LPC_ORDER ]; |
| 51 | silk_float LPC_res[ MAX_FRAME_LENGTH + MAX_NB_SUBFR * MAX_LPC_ORDER ]; |
| 52 | |
| 53 | subfr_length = psEncC->subfr_length + psEncC->predictLPCOrder; |
| 54 | |
| 55 | /* Default: No interpolation */ |
| 56 | psEncC->indices.NLSFInterpCoef_Q2 = 4; |
| 57 | |
| 58 | /* Burg AR analysis for the full frame */ |
| 59 | res_nrg = silk_burg_modified_FLP( a, x, minInvGain, subfr_length, psEncC->nb_subfr, psEncC->predictLPCOrder ); |
| 60 | |
| 61 | if( psEncC->useInterpolatedNLSFs && !psEncC->first_frame_after_reset && psEncC->nb_subfr == MAX_NB_SUBFR ) { |
| 62 | /* Optimal solution for last 10 ms; subtract residual energy here, as that's easier than */ |
| 63 | /* adding it to the residual energy of the first 10 ms in each iteration of the search below */ |
| 64 | res_nrg -= silk_burg_modified_FLP( a_tmp, x + ( MAX_NB_SUBFR / 2 ) * subfr_length, minInvGain, subfr_length, MAX_NB_SUBFR / 2, psEncC->predictLPCOrder ); |
| 65 | |
| 66 | /* Convert to NLSFs */ |
| 67 | silk_A2NLSF_FLP( NLSF_Q15, a_tmp, psEncC->predictLPCOrder ); |
| 68 | |
| 69 | /* Search over interpolation indices to find the one with lowest residual energy */ |
| 70 | res_nrg_2nd = silk_float_MAX; |
| 71 | for( k = 3; k >= 0; k-- ) { |
| 72 | /* Interpolate NLSFs for first half */ |
| 73 | silk_interpolate( NLSF0_Q15, psEncC->prev_NLSFq_Q15, NLSF_Q15, k, psEncC->predictLPCOrder ); |
| 74 | |
| 75 | /* Convert to LPC for residual energy evaluation */ |
| 76 | silk_NLSF2A_FLP( a_tmp, NLSF0_Q15, psEncC->predictLPCOrder ); |
| 77 | |
| 78 | /* Calculate residual energy with LSF interpolation */ |
| 79 | silk_LPC_analysis_filter_FLP( LPC_res, a_tmp, x, 2 * subfr_length, psEncC->predictLPCOrder ); |
| 80 | res_nrg_interp = (silk_float)( |
| 81 | silk_energy_FLP( LPC_res + psEncC->predictLPCOrder, subfr_length - psEncC->predictLPCOrder ) + |
| 82 | silk_energy_FLP( LPC_res + psEncC->predictLPCOrder + subfr_length, subfr_length - psEncC->predictLPCOrder ) ); |
| 83 | |
| 84 | /* Determine whether current interpolated NLSFs are best so far */ |
| 85 | if( res_nrg_interp < res_nrg ) { |
| 86 | /* Interpolation has lower residual energy */ |
| 87 | res_nrg = res_nrg_interp; |
| 88 | psEncC->indices.NLSFInterpCoef_Q2 = (opus_int8)k; |
| 89 | } else if( res_nrg_interp > res_nrg_2nd ) { |
| 90 | /* No reason to continue iterating - residual energies will continue to climb */ |
| 91 | break; |
| 92 | } |
| 93 | res_nrg_2nd = res_nrg_interp; |
| 94 | } |
| 95 | } |
| 96 | |
| 97 | if( psEncC->indices.NLSFInterpCoef_Q2 == 4 ) { |
| 98 | /* NLSF interpolation is currently inactive, calculate NLSFs from full frame AR coefficients */ |
| 99 | silk_A2NLSF_FLP( NLSF_Q15, a, psEncC->predictLPCOrder ); |
| 100 | } |
| 101 | |
| 102 | silk_assert( psEncC->indices.NLSFInterpCoef_Q2 == 4 || |
| 103 | ( psEncC->useInterpolatedNLSFs && !psEncC->first_frame_after_reset && psEncC->nb_subfr == MAX_NB_SUBFR ) ); |
| 104 | } |