mirror of https://git.ffmpeg.org/ffmpeg.git
85 lines
3.0 KiB
C
85 lines
3.0 KiB
C
/*
|
|
* Copyright (C) 2012 Michael Niedermayer (michaelni@gmx.at)
|
|
*
|
|
* This file is part of libswresample
|
|
*
|
|
* libswresample is free software; you can redistribute it and/or
|
|
* modify it under the terms of the GNU Lesser General Public
|
|
* License as published by the Free Software Foundation; either
|
|
* version 2.1 of the License, or (at your option) any later version.
|
|
*
|
|
* libswresample is distributed in the hope that it will be useful,
|
|
* but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
|
|
* Lesser General Public License for more details.
|
|
*
|
|
* You should have received a copy of the GNU Lesser General Public
|
|
* License along with libswresample; if not, write to the Free Software
|
|
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
|
|
*/
|
|
|
|
#include "libavutil/avassert.h"
|
|
#include "swresample_internal.h"
|
|
|
|
void swri_get_dither(SwrContext *s, void *dst, int len, unsigned seed, enum AVSampleFormat out_fmt, enum AVSampleFormat in_fmt) {
|
|
double scale = 0;
|
|
#define TMP_EXTRA 2
|
|
double *tmp = av_malloc((len + TMP_EXTRA) * sizeof(double));
|
|
int i;
|
|
|
|
if(in_fmt == AV_SAMPLE_FMT_FLT || in_fmt == AV_SAMPLE_FMT_DBL){
|
|
if(out_fmt == AV_SAMPLE_FMT_S32) scale = 1.0/(1L<<31);
|
|
if(out_fmt == AV_SAMPLE_FMT_S16) scale = 1.0/(1L<<15);
|
|
if(out_fmt == AV_SAMPLE_FMT_U8 ) scale = 1.0/(1L<< 7);
|
|
}
|
|
if(in_fmt == AV_SAMPLE_FMT_S32 && out_fmt == AV_SAMPLE_FMT_S16) scale = 1L<<16;
|
|
if(in_fmt == AV_SAMPLE_FMT_S32 && out_fmt == AV_SAMPLE_FMT_U8 ) scale = 1L<<24;
|
|
if(in_fmt == AV_SAMPLE_FMT_S16 && out_fmt == AV_SAMPLE_FMT_U8 ) scale = 1L<<8;
|
|
|
|
scale *= s->dither_scale;
|
|
|
|
for(i=0; i<len + TMP_EXTRA; i++){
|
|
double v;
|
|
seed = seed* 1664525 + 1013904223;
|
|
|
|
switch(s->dither_method){
|
|
case SWR_DITHER_RECTANGULAR: v= ((double)seed) / UINT_MAX - 0.5; break;
|
|
case SWR_DITHER_TRIANGULAR :
|
|
case SWR_DITHER_TRIANGULAR_HIGHPASS :
|
|
v = ((double)seed) / UINT_MAX;
|
|
seed = seed*1664525 + 1013904223;
|
|
v-= ((double)seed) / UINT_MAX;
|
|
break;
|
|
default: av_assert0(0);
|
|
}
|
|
tmp[i] = v;
|
|
}
|
|
|
|
for(i=0; i<len; i++){
|
|
double v;
|
|
|
|
switch(s->dither_method){
|
|
case SWR_DITHER_RECTANGULAR:
|
|
case SWR_DITHER_TRIANGULAR :
|
|
v = tmp[i];
|
|
break;
|
|
case SWR_DITHER_TRIANGULAR_HIGHPASS :
|
|
v = (- tmp[i] + 2*tmp[i+1] - tmp[i+2]) / sqrt(6);
|
|
break;
|
|
default: av_assert0(0);
|
|
}
|
|
|
|
v*= scale;
|
|
|
|
switch(in_fmt){
|
|
case AV_SAMPLE_FMT_S16: ((int16_t*)dst)[i] = v; break;
|
|
case AV_SAMPLE_FMT_S32: ((int32_t*)dst)[i] = v; break;
|
|
case AV_SAMPLE_FMT_FLT: ((float *)dst)[i] = v; break;
|
|
case AV_SAMPLE_FMT_DBL: ((double *)dst)[i] = v; break;
|
|
default: av_assert0(0);
|
|
}
|
|
}
|
|
|
|
av_free(tmp);
|
|
}
|