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media/libopus/silk/fixed/find_LPC_FIX.c@ac0c01689b40 (annotated)

media/libopus/silk/fixed/find_LPC_FIX.c

Thu, 15 Jan 2015 15:59:08 +0100

author
Michael Schloh von Bennewitz <michael@schloh.com>
date
Thu, 15 Jan 2015 15:59:08 +0100
branch
TOR_BUG_9701
changeset 10
ac0c01689b40
permissions
-rw-r--r--

Implement a real Private Browsing Mode condition by changing the API/ABI;
This solves Tor bug #9701, complying with disk avoidance documented in
https://www.torproject.org/projects/torbrowser/design/#disk-avoidance.

michael@0 1 /***********************************************************************
michael@0 2 Copyright (c) 2006-2011, Skype Limited. All rights reserved.
michael@0 3 Redistribution and use in source and binary forms, with or without
michael@0 4 modification, are permitted provided that the following conditions
michael@0 5 are met:
michael@0 6 - Redistributions of source code must retain the above copyright notice,
michael@0 7 this list of conditions and the following disclaimer.
michael@0 8 - Redistributions in binary form must reproduce the above copyright
michael@0 9 notice, this list of conditions and the following disclaimer in the
michael@0 10 documentation and/or other materials provided with the distribution.
michael@0 11 - Neither the name of Internet Society, IETF or IETF Trust, nor the
michael@0 12 names of specific contributors, may be used to endorse or promote
michael@0 13 products derived from this software without specific prior written
michael@0 14 permission.
michael@0 15 THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
michael@0 16 AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
michael@0 17 IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
michael@0 18 ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
michael@0 19 LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
michael@0 20 CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
michael@0 21 SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
michael@0 22 INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
michael@0 23 CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
michael@0 24 ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
michael@0 25 POSSIBILITY OF SUCH DAMAGE.
michael@0 26 ***********************************************************************/
michael@0 27
michael@0 28 #ifdef HAVE_CONFIG_H
michael@0 29 #include "config.h"
michael@0 30 #endif
michael@0 31
michael@0 32 #include "main_FIX.h"
michael@0 33 #include "stack_alloc.h"
michael@0 34 #include "tuning_parameters.h"
michael@0 35
michael@0 36 /* Finds LPC vector from correlations, and converts to NLSF */
michael@0 37 void silk_find_LPC_FIX(
michael@0 38 silk_encoder_state *psEncC, /* I/O Encoder state */
michael@0 39 opus_int16 NLSF_Q15[], /* O NLSFs */
michael@0 40 const opus_int16 x[], /* I Input signal */
michael@0 41 const opus_int32 minInvGain_Q30 /* I Inverse of max prediction gain */
michael@0 42 )
michael@0 43 {
michael@0 44 opus_int k, subfr_length;
michael@0 45 opus_int32 a_Q16[ MAX_LPC_ORDER ];
michael@0 46 opus_int isInterpLower, shift;
michael@0 47 opus_int32 res_nrg0, res_nrg1;
michael@0 48 opus_int rshift0, rshift1;
michael@0 49
michael@0 50 /* Used only for LSF interpolation */
michael@0 51 opus_int32 a_tmp_Q16[ MAX_LPC_ORDER ], res_nrg_interp, res_nrg, res_tmp_nrg;
michael@0 52 opus_int res_nrg_interp_Q, res_nrg_Q, res_tmp_nrg_Q;
michael@0 53 opus_int16 a_tmp_Q12[ MAX_LPC_ORDER ];
michael@0 54 opus_int16 NLSF0_Q15[ MAX_LPC_ORDER ];
michael@0 55 SAVE_STACK;
michael@0 56
michael@0 57 subfr_length = psEncC->subfr_length + psEncC->predictLPCOrder;
michael@0 58
michael@0 59 /* Default: no interpolation */
michael@0 60 psEncC->indices.NLSFInterpCoef_Q2 = 4;
michael@0 61
michael@0 62 /* Burg AR analysis for the full frame */
michael@0 63 silk_burg_modified( &res_nrg, &res_nrg_Q, a_Q16, x, minInvGain_Q30, subfr_length, psEncC->nb_subfr, psEncC->predictLPCOrder, psEncC->arch );
michael@0 64
michael@0 65 if( psEncC->useInterpolatedNLSFs && !psEncC->first_frame_after_reset && psEncC->nb_subfr == MAX_NB_SUBFR ) {
michael@0 66 VARDECL( opus_int16, LPC_res );
michael@0 67
michael@0 68 /* Optimal solution for last 10 ms */
michael@0 69 silk_burg_modified( &res_tmp_nrg, &res_tmp_nrg_Q, a_tmp_Q16, x + 2 * subfr_length, minInvGain_Q30, subfr_length, 2, psEncC->predictLPCOrder, psEncC->arch );
michael@0 70
michael@0 71 /* subtract residual energy here, as that's easier than adding it to the */
michael@0 72 /* residual energy of the first 10 ms in each iteration of the search below */
michael@0 73 shift = res_tmp_nrg_Q - res_nrg_Q;
michael@0 74 if( shift >= 0 ) {
michael@0 75 if( shift < 32 ) {
michael@0 76 res_nrg = res_nrg - silk_RSHIFT( res_tmp_nrg, shift );
michael@0 77 }
michael@0 78 } else {
michael@0 79 silk_assert( shift > -32 );
michael@0 80 res_nrg = silk_RSHIFT( res_nrg, -shift ) - res_tmp_nrg;
michael@0 81 res_nrg_Q = res_tmp_nrg_Q;
michael@0 82 }
michael@0 83
michael@0 84 /* Convert to NLSFs */
michael@0 85 silk_A2NLSF( NLSF_Q15, a_tmp_Q16, psEncC->predictLPCOrder );
michael@0 86
michael@0 87 ALLOC( LPC_res, 2 * subfr_length, opus_int16 );
michael@0 88
michael@0 89 /* Search over interpolation indices to find the one with lowest residual energy */
michael@0 90 for( k = 3; k >= 0; k-- ) {
michael@0 91 /* Interpolate NLSFs for first half */
michael@0 92 silk_interpolate( NLSF0_Q15, psEncC->prev_NLSFq_Q15, NLSF_Q15, k, psEncC->predictLPCOrder );
michael@0 93
michael@0 94 /* Convert to LPC for residual energy evaluation */
michael@0 95 silk_NLSF2A( a_tmp_Q12, NLSF0_Q15, psEncC->predictLPCOrder );
michael@0 96
michael@0 97 /* Calculate residual energy with NLSF interpolation */
michael@0 98 silk_LPC_analysis_filter( LPC_res, x, a_tmp_Q12, 2 * subfr_length, psEncC->predictLPCOrder );
michael@0 99
michael@0 100 silk_sum_sqr_shift( &res_nrg0, &rshift0, LPC_res + psEncC->predictLPCOrder, subfr_length - psEncC->predictLPCOrder );
michael@0 101 silk_sum_sqr_shift( &res_nrg1, &rshift1, LPC_res + psEncC->predictLPCOrder + subfr_length, subfr_length - psEncC->predictLPCOrder );
michael@0 102
michael@0 103 /* Add subframe energies from first half frame */
michael@0 104 shift = rshift0 - rshift1;
michael@0 105 if( shift >= 0 ) {
michael@0 106 res_nrg1 = silk_RSHIFT( res_nrg1, shift );
michael@0 107 res_nrg_interp_Q = -rshift0;
michael@0 108 } else {
michael@0 109 res_nrg0 = silk_RSHIFT( res_nrg0, -shift );
michael@0 110 res_nrg_interp_Q = -rshift1;
michael@0 111 }
michael@0 112 res_nrg_interp = silk_ADD32( res_nrg0, res_nrg1 );
michael@0 113
michael@0 114 /* Compare with first half energy without NLSF interpolation, or best interpolated value so far */
michael@0 115 shift = res_nrg_interp_Q - res_nrg_Q;
michael@0 116 if( shift >= 0 ) {
michael@0 117 if( silk_RSHIFT( res_nrg_interp, shift ) < res_nrg ) {
michael@0 118 isInterpLower = silk_TRUE;
michael@0 119 } else {
michael@0 120 isInterpLower = silk_FALSE;
michael@0 121 }
michael@0 122 } else {
michael@0 123 if( -shift < 32 ) {
michael@0 124 if( res_nrg_interp < silk_RSHIFT( res_nrg, -shift ) ) {
michael@0 125 isInterpLower = silk_TRUE;
michael@0 126 } else {
michael@0 127 isInterpLower = silk_FALSE;
michael@0 128 }
michael@0 129 } else {
michael@0 130 isInterpLower = silk_FALSE;
michael@0 131 }
michael@0 132 }
michael@0 133
michael@0 134 /* Determine whether current interpolated NLSFs are best so far */
michael@0 135 if( isInterpLower == silk_TRUE ) {
michael@0 136 /* Interpolation has lower residual energy */
michael@0 137 res_nrg = res_nrg_interp;
michael@0 138 res_nrg_Q = res_nrg_interp_Q;
michael@0 139 psEncC->indices.NLSFInterpCoef_Q2 = (opus_int8)k;
michael@0 140 }
michael@0 141 }
michael@0 142 }
michael@0 143
michael@0 144 if( psEncC->indices.NLSFInterpCoef_Q2 == 4 ) {
michael@0 145 /* NLSF interpolation is currently inactive, calculate NLSFs from full frame AR coefficients */
michael@0 146 silk_A2NLSF( NLSF_Q15, a_Q16, psEncC->predictLPCOrder );
michael@0 147 }
michael@0 148
michael@0 149 silk_assert( psEncC->indices.NLSFInterpCoef_Q2 == 4 || ( psEncC->useInterpolatedNLSFs && !psEncC->first_frame_after_reset && psEncC->nb_subfr == MAX_NB_SUBFR ) );
michael@0 150 RESTORE_STACK;
michael@0 151 }

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