git.sesse.net Git - ffmpeg/blob - libswresample/resample_template.c

   1 /*
   2  * audio resampling
   3  * Copyright (c) 2004-2012 Michael Niedermayer <michaelni@gmx.at>
   4  *
   5  * This file is part of FFmpeg.
   6  *
   7  * FFmpeg is free software; you can redistribute it and/or
   8  * modify it under the terms of the GNU Lesser General Public
   9  * License as published by the Free Software Foundation; either
  10  * version 2.1 of the License, or (at your option) any later version.
  11  *
  12  * FFmpeg is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  15  * Lesser General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU Lesser General Public
  18  * License along with FFmpeg; if not, write to the Free Software
  19  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  20  */
  21
  22 /**
  23  * @file
  24  * audio resampling
  25  * @author Michael Niedermayer <michaelni@gmx.at>
  26  */
  27
  28 int RENAME(swri_resample)(ResampleContext *c, DELEM *dst, const DELEM *src, int *consumed, int src_size, int dst_size, int update_ctx){
  29     int dst_index, i;
  30     int index= c->index;
  31     int frac= c->frac;
  32     int dst_incr_frac= c->dst_incr % c->src_incr;
  33     int dst_incr=      c->dst_incr / c->src_incr;
  34     int compensation_distance= c->compensation_distance;
  35
  36     av_assert1(c->filter_shift == FILTER_SHIFT);
  37     av_assert1(c->felem_size == sizeof(FELEM));
  38
  39     if(compensation_distance == 0 && c->filter_length == 1 && c->phase_shift==0){
  40         int64_t index2= ((int64_t)index)<<32;
  41         int64_t incr= (1LL<<32) * c->dst_incr / c->src_incr;
  42         dst_size= FFMIN(dst_size, (src_size-1-index) * (int64_t)c->src_incr / c->dst_incr);
  43
  44         for(dst_index=0; dst_index < dst_size; dst_index++){
  45             dst[dst_index] = src[index2>>32];
  46             index2 += incr;
  47         }
  48         index += dst_index * dst_incr;
  49         index += (frac + dst_index * (int64_t)dst_incr_frac) / c->src_incr;
  50         frac   = (frac + dst_index * (int64_t)dst_incr_frac) % c->src_incr;
  51     }else if(compensation_distance == 0 && !c->linear && index >= 0){
  52         for(dst_index=0; dst_index < dst_size; dst_index++){
  53             FELEM *filter= ((FELEM*)c->filter_bank) + c->filter_alloc*(index & c->phase_mask);
  54             int sample_index= index >> c->phase_shift;
  55
  56             if(sample_index + c->filter_length > src_size){
  57                 break;
  58             }else{
  59 #ifdef COMMON_CORE
  60                 COMMON_CORE
  61 #else
  62                 FELEM2 val=0;
  63                 for(i=0; i<c->filter_length; i++){
  64                     val += src[sample_index + i] * (FELEM2)filter[i];
  65                 }
  66                 OUT(dst[dst_index], val);
  67 #endif
  68             }
  69
  70             frac += dst_incr_frac;
  71             index += dst_incr;
  72             if(frac >= c->src_incr){
  73                 frac -= c->src_incr;
  74                 index++;
  75             }
  76         }
  77     }else{
  78         for(dst_index=0; dst_index < dst_size; dst_index++){
  79             FELEM *filter= ((FELEM*)c->filter_bank) + c->filter_alloc*(index & c->phase_mask);
  80             int sample_index= index >> c->phase_shift;
  81             FELEM2 val=0;
  82
  83             if(sample_index + c->filter_length > src_size || -sample_index >= src_size){
  84                 break;
  85             }else if(sample_index < 0){
  86                 for(i=0; i<c->filter_length; i++)
  87                     val += src[FFABS(sample_index + i)] * filter[i];
  88             }else if(c->linear){
  89                 FELEM2 v2=0;
  90                 for(i=0; i<c->filter_length; i++){
  91                     val += src[sample_index + i] * (FELEM2)filter[i];
  92                     v2  += src[sample_index + i] * (FELEM2)filter[i + c->filter_alloc];
  93                 }
  94                 val+=(v2-val)*(FELEML)frac / c->src_incr;
  95             }else{
  96                 for(i=0; i<c->filter_length; i++){
  97                     val += src[sample_index + i] * (FELEM2)filter[i];
  98                 }
  99             }
 100
 101             OUT(dst[dst_index], val);
 102
 103             frac += dst_incr_frac;
 104             index += dst_incr;
 105             if(frac >= c->src_incr){
 106                 frac -= c->src_incr;
 107                 index++;
 108             }
 109
 110             if(dst_index + 1 == compensation_distance){
 111                 compensation_distance= 0;
 112                 dst_incr_frac= c->ideal_dst_incr % c->src_incr;
 113                 dst_incr=      c->ideal_dst_incr / c->src_incr;
 114             }
 115         }
 116     }
 117     *consumed= FFMAX(index, 0) >> c->phase_shift;
 118     if(index>=0) index &= c->phase_mask;
 119
 120     if(compensation_distance){
 121         compensation_distance -= dst_index;
 122         av_assert1(compensation_distance > 0);
 123     }
 124     if(update_ctx){
 125         c->frac= frac;
 126         c->index= index;
 127         c->dst_incr= dst_incr_frac + c->src_incr*dst_incr;
 128         c->compensation_distance= compensation_distance;
 129     }
 130 #if 0
 131     if(update_ctx && !c->compensation_distance){
 132 #undef rand
 133         av_resample_compensate(c, rand() % (8000*2) - 8000, 8000*2);
 134 av_log(NULL, AV_LOG_DEBUG, "%d %d %d\n", c->dst_incr, c->ideal_dst_incr, c->compensation_distance);
 135     }
 136 #endif
 137
 138     return dst_index;
 139 }