mirror of
https://github.com/FFmpeg/FFmpeg.git
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114 lines
4.1 KiB
C
114 lines
4.1 KiB
C
/*
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* audio resampling
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* Copyright (c) 2004-2012 Michael Niedermayer <michaelni@gmx.at>
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*
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* This file is part of FFmpeg.
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*
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* FFmpeg is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* FFmpeg is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with FFmpeg; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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/**
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* @file
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* audio resampling
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* @author Michael Niedermayer <michaelni@gmx.at>
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*/
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int RENAME(swri_resample)(ResampleContext *c, DELEM *dst, const DELEM *src, int *consumed, int src_size, int dst_size, int update_ctx){
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int dst_index, i;
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int index= c->index;
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int frac= c->frac;
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int dst_incr_frac= c->dst_incr % c->src_incr;
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int dst_incr= c->dst_incr / c->src_incr;
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int compensation_distance= c->compensation_distance;
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av_assert1(c->filter_shift == FILTER_SHIFT);
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av_assert1(c->felem_size == sizeof(FELEM));
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if(compensation_distance == 0 && c->filter_length == 1 && c->phase_shift==0){
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int64_t index2= ((int64_t)index)<<32;
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int64_t incr= (1LL<<32) * c->dst_incr / c->src_incr;
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dst_size= FFMIN(dst_size, (src_size-1-index) * (int64_t)c->src_incr / c->dst_incr);
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for(dst_index=0; dst_index < dst_size; dst_index++){
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dst[dst_index] = src[index2>>32];
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index2 += incr;
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}
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index += dst_index * dst_incr;
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index += (frac + dst_index * (int64_t)dst_incr_frac) / c->src_incr;
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frac = (frac + dst_index * (int64_t)dst_incr_frac) % c->src_incr;
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}else{
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for(dst_index=0; dst_index < dst_size; dst_index++){
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FELEM *filter= ((FELEM*)c->filter_bank) + c->filter_length*(index & c->phase_mask);
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int sample_index= index >> c->phase_shift;
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FELEM2 val=0;
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if(sample_index + c->filter_length > src_size || -sample_index >= src_size){
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break;
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}else if(sample_index < 0){
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for(i=0; i<c->filter_length; i++)
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val += src[FFABS(sample_index + i)] * filter[i];
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}else if(c->linear){
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FELEM2 v2=0;
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for(i=0; i<c->filter_length; i++){
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val += src[sample_index + i] * (FELEM2)filter[i];
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v2 += src[sample_index + i] * (FELEM2)filter[i + c->filter_length];
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}
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val+=(v2-val)*(FELEML)frac / c->src_incr;
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}else{
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for(i=0; i<c->filter_length; i++){
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val += src[sample_index + i] * (FELEM2)filter[i];
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}
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}
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OUT(dst[dst_index], val);
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frac += dst_incr_frac;
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index += dst_incr;
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if(frac >= c->src_incr){
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frac -= c->src_incr;
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index++;
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}
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if(dst_index + 1 == compensation_distance){
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compensation_distance= 0;
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dst_incr_frac= c->ideal_dst_incr % c->src_incr;
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dst_incr= c->ideal_dst_incr / c->src_incr;
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}
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}
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}
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*consumed= FFMAX(index, 0) >> c->phase_shift;
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if(index>=0) index &= c->phase_mask;
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if(compensation_distance){
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compensation_distance -= dst_index;
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assert(compensation_distance > 0);
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}
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if(update_ctx){
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c->frac= frac;
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c->index= index;
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c->dst_incr= dst_incr_frac + c->src_incr*dst_incr;
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c->compensation_distance= compensation_distance;
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}
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#if 0
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if(update_ctx && !c->compensation_distance){
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#undef rand
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av_resample_compensate(c, rand() % (8000*2) - 8000, 8000*2);
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av_log(NULL, AV_LOG_DEBUG, "%d %d %d\n", c->dst_incr, c->ideal_dst_incr, c->compensation_distance);
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}
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#endif
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return dst_index;
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}
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