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 "main_FIX.h" 33 #include "tuning_parameters.h" 34 35 /* Finds LPC vector from correlations, and converts to NLSF */ 36 void silk_find_LPC_FIX( 37 silk_encoder_state *psEncC, /* I/O Encoder state */ 38 opus_int16 NLSF_Q15[], /* O NLSFs */ 39 const opus_int16 x[], /* I Input signal */ 40 const opus_int32 minInvGain_Q30 /* I Inverse of max prediction gain */ 41 ) 42 { 43 opus_int k, subfr_length; 44 opus_int32 a_Q16[ MAX_LPC_ORDER ]; 45 opus_int isInterpLower, shift; 46 opus_int32 res_nrg0, res_nrg1; 47 opus_int rshift0, rshift1; 48 49 /* Used only for LSF interpolation */ 50 opus_int32 a_tmp_Q16[ MAX_LPC_ORDER ], res_nrg_interp, res_nrg, res_tmp_nrg; 51 opus_int res_nrg_interp_Q, res_nrg_Q, res_tmp_nrg_Q; 52 opus_int16 a_tmp_Q12[ MAX_LPC_ORDER ]; 53 opus_int16 NLSF0_Q15[ MAX_LPC_ORDER ]; 54 opus_int16 LPC_res[ MAX_FRAME_LENGTH + MAX_NB_SUBFR * MAX_LPC_ORDER ]; 55 56 subfr_length = psEncC->subfr_length + psEncC->predictLPCOrder; 57 58 /* Default: no interpolation */ 59 psEncC->indices.NLSFInterpCoef_Q2 = 4; 60 61 /* Burg AR analysis for the full frame */ 62 silk_burg_modified( &res_nrg, &res_nrg_Q, a_Q16, x, minInvGain_Q30, subfr_length, psEncC->nb_subfr, psEncC->predictLPCOrder ); 63 64 if( psEncC->useInterpolatedNLSFs && !psEncC->first_frame_after_reset && psEncC->nb_subfr == MAX_NB_SUBFR ) { 65 /* Optimal solution for last 10 ms */ 66 silk_burg_modified( &res_tmp_nrg, &res_tmp_nrg_Q, a_tmp_Q16, x + 2 * subfr_length, minInvGain_Q30, subfr_length, 2, psEncC->predictLPCOrder ); 67 68 /* subtract residual energy here, as that's easier than adding it to the */ 69 /* residual energy of the first 10 ms in each iteration of the search below */ 70 shift = res_tmp_nrg_Q - res_nrg_Q; 71 if( shift >= 0 ) { 72 if( shift < 32 ) { 73 res_nrg = res_nrg - silk_RSHIFT( res_tmp_nrg, shift ); 74 } 75 } else { 76 silk_assert( shift > -32 ); 77 res_nrg = silk_RSHIFT( res_nrg, -shift ) - res_tmp_nrg; 78 res_nrg_Q = res_tmp_nrg_Q; 79 } 80 81 /* Convert to NLSFs */ 82 silk_A2NLSF( NLSF_Q15, a_tmp_Q16, psEncC->predictLPCOrder ); 83 84 /* Search over interpolation indices to find the one with lowest residual energy */ 85 for( k = 3; k >= 0; k-- ) { 86 /* Interpolate NLSFs for first half */ 87 silk_interpolate( NLSF0_Q15, psEncC->prev_NLSFq_Q15, NLSF_Q15, k, psEncC->predictLPCOrder ); 88 89 /* Convert to LPC for residual energy evaluation */ 90 silk_NLSF2A( a_tmp_Q12, NLSF0_Q15, psEncC->predictLPCOrder ); 91 92 /* Calculate residual energy with NLSF interpolation */ 93 silk_LPC_analysis_filter( LPC_res, x, a_tmp_Q12, 2 * subfr_length, psEncC->predictLPCOrder ); 94 95 silk_sum_sqr_shift( &res_nrg0, &rshift0, LPC_res + psEncC->predictLPCOrder, subfr_length - psEncC->predictLPCOrder ); 96 silk_sum_sqr_shift( &res_nrg1, &rshift1, LPC_res + psEncC->predictLPCOrder + subfr_length, subfr_length - psEncC->predictLPCOrder ); 97 98 /* Add subframe energies from first half frame */ 99 shift = rshift0 - rshift1; 100 if( shift >= 0 ) { 101 res_nrg1 = silk_RSHIFT( res_nrg1, shift ); 102 res_nrg_interp_Q = -rshift0; 103 } else { 104 res_nrg0 = silk_RSHIFT( res_nrg0, -shift ); 105 res_nrg_interp_Q = -rshift1; 106 } 107 res_nrg_interp = silk_ADD32( res_nrg0, res_nrg1 ); 108 109 /* Compare with first half energy without NLSF interpolation, or best interpolated value so far */ 110 shift = res_nrg_interp_Q - res_nrg_Q; 111 if( shift >= 0 ) { 112 if( silk_RSHIFT( res_nrg_interp, shift ) < res_nrg ) { 113 isInterpLower = silk_TRUE; 114 } else { 115 isInterpLower = silk_FALSE; 116 } 117 } else { 118 if( -shift < 32 ) { 119 if( res_nrg_interp < silk_RSHIFT( res_nrg, -shift ) ) { 120 isInterpLower = silk_TRUE; 121 } else { 122 isInterpLower = silk_FALSE; 123 } 124 } else { 125 isInterpLower = silk_FALSE; 126 } 127 } 128 129 /* Determine whether current interpolated NLSFs are best so far */ 130 if( isInterpLower == silk_TRUE ) { 131 /* Interpolation has lower residual energy */ 132 res_nrg = res_nrg_interp; 133 res_nrg_Q = res_nrg_interp_Q; 134 psEncC->indices.NLSFInterpCoef_Q2 = (opus_int8)k; 135 } 136 } 137 } 138 139 if( psEncC->indices.NLSFInterpCoef_Q2 == 4 ) { 140 /* NLSF interpolation is currently inactive, calculate NLSFs from full frame AR coefficients */ 141 silk_A2NLSF( NLSF_Q15, a_Q16, psEncC->predictLPCOrder ); 142 } 143 144 silk_assert( psEncC->indices.NLSFInterpCoef_Q2 == 4 || ( psEncC->useInterpolatedNLSFs && !psEncC->first_frame_after_reset && psEncC->nb_subfr == MAX_NB_SUBFR ) ); 145 } 146
