ffmpeg中sws_scale()用法实例
ffmpeg中sws_scale()用法实例
视频编码 2009-06-30 10:02:27 阅读1185 评论0 字号：大 中 小 订阅
/*
* Copyright (C) 2003 Michael Niedermayer <[email protected] >
*
* This file is part of FFmpeg.
*
* FFmpeg 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.
*
* FFmpeg 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 FFmpeg; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <inttypes.h>
#include <stdarg.h>
#undef HAVE_AV_CONFIG_H
#include "libavutil/avutil.h"
#include "swscale.h"
#include "swscale_internal.h"
static uint64_t getSSD(uint8_t *src1, uint8_t *src2, int stride1, int stride2, int w, int h){
int x,y;
uint64_t ssd=0;
//printf("%d %d/n", w, h);
for (y=0; y<h; y++){
for (x=0; x<w; x++){
int d= src1[x + y*stride1] - src2[x + y*stride2];
ssd+= d*d;
//printf("%d", abs(src1[x + y*stride1] - src2[x + y*stride2])/26 );
}
//printf("/n");
}
return ssd;
}
// test by ref -> src -> dst -> out & compare out against ref
// ref & out are YV12
static int doTest(uint8_t *ref[3], int refStride[3], int w, int h, int srcFormat, int dstFormat,
int srcW, int srcH, int dstW, int dstH, int flags){
uint8_t *src[3];
uint8_t *dst[3];
uint8_t *out[3];
int srcStride[3], dstStride[3];
int i;
uint64_t ssdY, ssdU, ssdV;
struct SwsContext *srcContext, *dstContext, *outContext;
int res;
res = 0;
for (i=0; i<3; i++){
// avoid stride % bpp != 0
if (srcFormat==PIX_FMT_RGB24 || srcFormat==PIX_FMT_BGR24)
srcStride[i]= srcW*3;
else
srcStride[i]= srcW*4;
if (dstFormat==PIX_FMT_RGB24 || dstFormat==PIX_FMT_BGR24)
dstStride[i]= dstW*3;
else
dstStride[i]= dstW*4;
src[i]= (uint8_t*) malloc(srcStride[i]*srcH);
dst[i]= (uint8_t*) malloc(dstStride[i]*dstH);
out[i]= (uint8_t*) malloc(refStride[i]*h);
if (!src[i] || !dst[i] || !out[i]) {
perror("Malloc");
res = -1;
goto end;
}
}
dstContext = outContext = NULL;
srcContext= sws_getContext(w, h, PIX_FMT_YUV420P, srcW, srcH, srcFormat, flags, NULL, NULL, NULL);
if (!srcContext) {
fprintf(stderr, "Failed to get %s ---> %s/n",
sws_format_name(PIX_FMT_YUV420P),
sws_format_name(srcFormat));
res = -1;
goto end;
}
dstContext= sws_getContext(srcW, srcH, srcFormat, dstW, dstH, dstFormat, flags, NULL, NULL, NULL);
if (!dstContext) {
fprintf(stderr, "Failed to get %s ---> %s/n",
sws_format_name(srcFormat),
sws_format_name(dstFormat));
res = -1;
goto end;
}
outContext= sws_getContext(dstW, dstH, dstFormat, w, h, PIX_FMT_YUV420P, flags, NULL, NULL, NULL);
if (!outContext) {
fprintf(stderr, "Failed to get %s ---> %s/n",
sws_format_name(dstFormat),
sws_format_name(PIX_FMT_YUV420P));
res = -1;
goto end;
}
// printf("test %X %X %X -> %X %X %X/n", (int)ref[0], (int)ref[1], (int)ref[2],
// (int)src[0], (int)src[1], (int)src[2]);
sws_scale(srcContext, ref, refStride, 0, h , src, srcStride);
sws_scale(dstContext, src, srcStride, 0, srcH, dst, dstStride);
sws_scale(outContext, dst, dstStride, 0, dstH, out, refStride);
ssdY= getSSD(ref[0], out[0], refStride[0], refStride[0], w, h);
ssdU= getSSD(ref[1], out[1], refStride[1], refStride[1], (w+1)>>1, (h+1)>>1);
ssdV= getSSD(ref[2], out[2], refStride[2], refStride[2], (w+1)>>1, (h+1)>>1);
if (srcFormat == PIX_FMT_GRAY8 || dstFormat==PIX_FMT_GRAY8) ssdU=ssdV=0; //FIXME check that output is really gray
ssdY/= w*h;
ssdU/= w*h/4;
ssdV/= w*h/4;
printf(" %s %dx%d -> %s %4dx%4d flags=%2d SSD=%5lld,%5lld,%5lld/n",
sws_format_name(srcFormat), srcW, srcH,
sws_format_name(dstFormat), dstW, dstH,
flags, ssdY, ssdU, ssdV);
fflush(stdout);
end:
sws_freeContext(srcContext);
sws_freeContext(dstContext);
sws_freeContext(outContext);
for (i=0; i<3; i++){
free(src[i]);
free(dst[i]);
free(out[i]);
}
return res;
}
static void selfTest(uint8_t *src[3], int stride[3], int w, int h){
enum PixelFormat srcFormat, dstFormat;
int srcW, srcH, dstW, dstH;
int flags;
for (srcFormat = 0; srcFormat < PIX_FMT_NB; srcFormat++) {
for (dstFormat = 0; dstFormat < PIX_FMT_NB; dstFormat++) {
printf("%s -> %s/n",
sws_format_name(srcFormat),
sws_format_name(dstFormat));
fflush(stdout);
srcW= w;
srcH= h;
for (dstW=w - w/3; dstW<= 4*w/3; dstW+= w/3){
for (dstH=h - h/3; dstH<= 4*h/3; dstH+= h/3){
for (flags=1; flags<33; flags*=2) {
int res;
res = doTest(src, stride, w, h, srcFormat, dstFormat,
srcW, srcH, dstW, dstH, flags);
if (res < 0) {
dstW = 4 * w / 3;
dstH = 4 * h / 3;
flags = 33;
}
}
}
}
}
}
}
#define W 96
#define H 96
int main(int argc, char **argv){
uint8_t *rgb_data = malloc (W*H*4);
uint8_t *rgb_src[3]= {rgb_data, NULL, NULL};
int rgb_stride[3]={4*W, 0, 0};
uint8_t *data = malloc (3*W*H);
uint8_t *src[3]= {data, data+W*H, data+W*H*2};
int stride[3]={W, W, W};
int x, y;
struct SwsContext *sws;
sws= sws_getContext(W/12, H/12, PIX_FMT_RGB32, W, H, PIX_FMT_YUV420P, 2, NULL, NULL, NULL);
for (y=0; y<H; y++){
for (x=0; x<W*4; x++){
rgb_data[ x + y*4*W]= random();
}
}
sws_scale(sws, rgb_src, rgb_stride, 0, H, src, stride);
selfTest(src, stride, W, H);
return 123;
}