FFMPEG:H264解码-SDL显示（RGB32、RGB24、YUV420P、YUV422） 分类： DirectX ffmpeg-SDL-VLC-Live555 VC++ 2014-11-25 17:45 726人阅读 评论(0) 收藏
FFMpeg对视频文件进行解码的大致流程
1. 注册所有容器格式: av_register_all()
2. 打开文件: av_open_input_file()
3. 从文件中提取流信息: av_find_stream_info()
4. 穷举所有的流，查找其中种类为CODEC_TYPE_VIDEO
5. 查找对应的解码器: avcodec_find_decoder()
6. 打开编解码器: avcodec_open()
7. 为解码帧分配内存: avcodec_alloc_frame()
8. 不停地从码流中提取出帧数据: av_read_frame()
9. 判断帧的类型，对于视频帧调用: avcodec_decode_video()
10. 解码完后，释放解码器: avcodec_close()
11. 关闭输入文件:av_close_input_file()
2. 打开文件: av_open_input_file()
3. 从文件中提取流信息: av_find_stream_info()
4. 穷举所有的流，查找其中种类为CODEC_TYPE_VIDEO
5. 查找对应的解码器: avcodec_find_decoder()
6. 打开编解码器: avcodec_open()
7. 为解码帧分配内存: avcodec_alloc_frame()
8. 不停地从码流中提取出帧数据: av_read_frame()
9. 判断帧的类型，对于视频帧调用: avcodec_decode_video()
10. 解码完后，释放解码器: avcodec_close()
11. 关闭输入文件:av_close_input_file()
extern "C"
{
#include <libavcodec/avcodec.h>
#include <libavformat/avformat.h>
#include <libswscale/swscale.h>
#include <libsdl/SDL.h>
#include <libsdl/SDL_thread.h>
};
void SaveFrame(AVFrame *pFrame, int width, int height, int iFrame)
{
FILE *pFile;
char szFilename[32];
int y;
// Open file
sprintf(szFilename, "frame%d.ppm", iFrame);
pFile=fopen(szFilename, "wb");
if(pFile==NULL)
return;
// Write header
fprintf(pFile, "P6\n%d %d\n255\n", width, height);
// Write pixel data
for(y=0; y<height; y++)
fwrite(pFrame->data[0]+y*pFrame->linesize[0], 1, width*3, pFile);
// Close file
fclose(pFile);
}
void CTest0Dlg::OnButton1()
{
// TODO: Add your control notification handler code here
AVFormatContext *pFormatCtx;
int i, videoStream;
AVCodecContext *pCodecCtx;
AVCodec *pCodec;
AVFrame *pFrame;
AVFrame *pFrameRGB;
AVPacket packet;
int frameFinished;
int numBytes;
uint8_t *buffer;
static int sws_flags = SWS_BICUBIC;
struct SwsContext *img_convert_ctx;
AVPicture pict;
// argc = 2;
char argv[100] = "d:\\temp\\VIDEO720576.264";
// argv[1] = "d:\\temp\\ff.mpg";
// /*注册所有可用的格式和编解码器*/
av_register_all();
// Open video file /*以输入方式打开一个媒体文件,也即源文件,codecs并没有打开,只读取了文件的头信息*/
if(av_open_input_file(&pFormatCtx, argv, NULL, 0, NULL)!=0)
return ; // Couldn't open file
// Retrieve stream information
/*通过读取媒体文件的中的包来获取媒体文件中的流信息,对于没有头信息的文件如(mpeg)是非常有用的,
// 该函数通常重算类似mpeg-2帧模式的真实帧率,该函数并未改变逻辑文件的position.
*/
if(av_find_stream_info(pFormatCtx)<0)
return ; // Couldn't find stream information
// Dump information about file onto standard error
//该函数的作用就是检查下初始化过程中设置的参数是否符合规范
dump_format(pFormatCtx, 0, argv, 0);
// Find the first video stream
videoStream=-1;
printf("%d\n",pFormatCtx->nb_streams);
getchar();
for(i=0; i<pFormatCtx->nb_streams; i++)
if(pFormatCtx->streams[i]->codec->codec_type==CODEC_TYPE_VIDEO&&videoStream < 0)
{
videoStream=i;
break;
}
if(videoStream==-1)
return ; // Didn't find a video stream
// Get a pointer to the codec context for the video stream
pCodecCtx=pFormatCtx->streams[videoStream]->codec;
// Find the decoder for the video stream
pCodec=avcodec_find_decoder(pCodecCtx->codec_id);
/*通过code ID查找一个已经注册的音视频编码器,查找编码器之前,必须先调用av_register_all注册所有支持的编码器
音视频编码器保存在一个链表中,查找过程中,函数从头到尾遍历链表,通过比较编码器的ID来查找
*/
if(pCodec==NULL) {
fprintf(stderr, "Unsupported codec!\n");
return ; // Codec not found
}
// Open codec
//使用给定的AVCodec初始化AVCodecContext
if(avcodec_open(pCodecCtx, pCodec)<0)
return ; // Could not open codec
//printf("name %s\n",pCodec->name);
//getchar();
// Allocate video frame
pFrame=avcodec_alloc_frame();
// Allocate an AVFrame structure
pFrameRGB=avcodec_alloc_frame();
if(pFrameRGB==NULL)
return ;
// Determine required buffer size and allocate buffer
numBytes=avpicture_get_size(PIX_FMT_RGB32, pCodecCtx->width,
pCodecCtx->height);
buffer=(uint8_t *)av_malloc(numBytes*sizeof(uint8_t));
// Assign appropriate parts of buffer to image planes in pFrameRGB
// Note that pFrameRGB is an AVFrame, but AVFrame is a superset
// of AVPicture
avpicture_fill((AVPicture *)pFrameRGB, buffer, PIX_FMT_RGB32,
pCodecCtx->width, pCodecCtx->height);
// Read frames and save first five frames to disk
i=0;
////////////////////////////////////////////////////////////////
if (SDL_Init(SDL_INIT_VIDEO) < 0)
{
fprintf(stderr, "can not initialize SDL:%s\n", SDL_GetError());
exit(1);
}
atexit(SDL_Quit);
SDL_Surface *screen;
screen = SDL_SetVideoMode(720, 576, 32, SDL_SWSURFACE|SDL_ANYFORMAT);
if ( screen == NULL )
{
exit(2);
}
SDL_Surface *image;
Uint32 rmask, gmask, bmask, amask;
/* SDL interprets each pixel as a 32-bit number, so our masks must depend
on the endianness (byte order) of the machine */
#if 0//SDL_BYTEORDER == SDL_BIG_ENDIAN
rmask = 0xff000000;
gmask = 0x00ff0000;
bmask = 0x0000ff00;
amask = 0x000000ff;
#else
rmask = 0x000000ff;
gmask = 0x0000ff00;
bmask = 0x00ff0000;
amask = 0xff000000;
#endif
image = SDL_CreateRGBSurface(SDL_SWSURFACE, 720, 576, 0,
rmask, gmask, bmask, NULL);
if(image == NULL)
{
//fprintf(stderr, "CreateRGBSurface failed: %s\n", SDL_GetError());
exit(1);
}
//////////////////////////////////////////////////////////////////
while(av_read_frame(pFormatCtx, &packet)>=0)
{
// Is this a packet from the video stream?
if(packet.stream_index==videoStream)
{
// Decode video frame
avcodec_decode_video(pCodecCtx, pFrame, &frameFinished,
packet.data, packet.size);
// Did we get a video frame?
if(frameFinished)
{
// Convert the image from its native format to RGB
img_convert_ctx = sws_getContext( pCodecCtx->width,
pCodecCtx->height,
pCodecCtx->pix_fmt,
pCodecCtx->width,
pCodecCtx->height,
PIX_FMT_RGB32,
sws_flags, NULL, NULL, NULL);
sws_scale(img_convert_ctx,pFrame->data,pFrame->linesize,0,pCodecCtx->height,pFrameRGB->data,pFrameRGB->linesize);
sws_freeContext(img_convert_ctx);
////////////////////////////////////////////////////////////////
memcpy(screen->pixels,buffer,720*576*4);
SDL_UpdateRect(screen, 0, 0, image->w, image->h);
/* Free the allocated BMP surface */
SDL_FreeSurface(image);
/////////////////////////////////////////////////////////////////
// Save the frame to disk
if((++i<=5))
SaveFrame(pFrameRGB, pCodecCtx->width, pCodecCtx->height, i);
}
}
// Free the packet that was allocated by av_read_frame
av_free_packet(&packet);
}
// Free the RGB image
av_free(buffer);
av_free(pFrameRGB);
// Free the YUV frame
av_free(pFrame);
// Close the codec
avcodec_close(pCodecCtx);
// Close the video file
av_close_input_file(pFormatCtx);
MessageBox("over");
}
void CTest0Dlg::OnButton2()
{
// TODO: Add your control notification handler code here
AVFormatContext *pFormatCtx;
int i, videoStream;
AVCodecContext *pCodecCtx;
AVCodec *pCodec;
AVFrame *pFrame;
AVFrame *pFrameRGB;
AVPacket packet;
int frameFinished;
int numBytes;
uint8_t *buffer;
static int sws_flags = SWS_BICUBIC;
struct SwsContext *img_convert_ctx;
AVPicture pict;
// argc = 2;
char argv[100] = "d:\\temp\\VIDEO720576.264";
// argv[1] = "d:\\temp\\ff.mpg";
// /*注册所有可用的格式和编解码器*/
av_register_all();
// Open video file /*以输入方式打开一个媒体文件,也即源文件,codecs并没有打开,只读取了文件的头信息*/
if(av_open_input_file(&pFormatCtx, argv, NULL, 0, NULL)!=0)
return ; // Couldn't open file
// Retrieve stream information
/*通过读取媒体文件的中的包来获取媒体文件中的流信息,对于没有头信息的文件如(mpeg)是非常有用的,
// 该函数通常重算类似mpeg-2帧模式的真实帧率,该函数并未改变逻辑文件的position.
*/
if(av_find_stream_info(pFormatCtx)<0)
return ; // Couldn't find stream information
// Dump information about file onto standard error
//该函数的作用就是检查下初始化过程中设置的参数是否符合规范
dump_format(pFormatCtx, 0, argv, 0);
// Find the first video stream
videoStream=-1;
printf("%d\n",pFormatCtx->nb_streams);
getchar();
for(i=0; i<pFormatCtx->nb_streams; i++)
if(pFormatCtx->streams[i]->codec->codec_type==CODEC_TYPE_VIDEO&&videoStream < 0)
{
videoStream=i;
break;
}
if(videoStream==-1)
return ; // Didn't find a video stream
// Get a pointer to the codec context for the video stream
pCodecCtx=pFormatCtx->streams[videoStream]->codec;
// Find the decoder for the video stream
pCodec=avcodec_find_decoder(pCodecCtx->codec_id);
/*通过code ID查找一个已经注册的音视频编码器,查找编码器之前,必须先调用av_register_all注册所有支持的编码器
音视频编码器保存在一个链表中,查找过程中,函数从头到尾遍历链表,通过比较编码器的ID来查找
*/
if(pCodec==NULL) {
fprintf(stderr, "Unsupported codec!\n");
return ; // Codec not found
}
// Open codec
//使用给定的AVCodec初始化AVCodecContext
if(avcodec_open(pCodecCtx, pCodec)<0)
return ; // Could not open codec
//printf("name %s\n",pCodec->name);
//getchar();
// Allocate video frame
pFrame=avcodec_alloc_frame();
// Allocate an AVFrame structure
pFrameRGB=avcodec_alloc_frame();
if(pFrameRGB==NULL)
return ;
// Determine required buffer size and allocate buffer
numBytes=avpicture_get_size(PIX_FMT_RGB24, pCodecCtx->width,
pCodecCtx->height);
buffer=(uint8_t *)av_malloc(numBytes*sizeof(uint8_t));
// Assign appropriate parts of buffer to image planes in pFrameRGB
// Note that pFrameRGB is an AVFrame, but AVFrame is a superset
// of AVPicture
avpicture_fill((AVPicture *)pFrameRGB, buffer, PIX_FMT_RGB24,
pCodecCtx->width, pCodecCtx->height);
// Read frames and save first five frames to disk
i=0;
////////////////////////////////////////////////////////////////
if (SDL_Init(SDL_INIT_VIDEO) < 0)
{
fprintf(stderr, "can not initialize SDL:%s\n", SDL_GetError());
exit(1);
}
atexit(SDL_Quit);
SDL_Surface *screen;
screen = SDL_SetVideoMode(720, 576, 24, SDL_SWSURFACE|SDL_ANYFORMAT);
if ( screen == NULL )
{
exit(2);
}
SDL_Surface *image;
Uint32 rmask, gmask, bmask, amask;
/* SDL interprets each pixel as a 32-bit number, so our masks must depend
on the endianness (byte order) of the machine */
#if 0//SDL_BYTEORDER == SDL_BIG_ENDIAN
rmask = 0xff000000;
gmask = 0x00ff0000;
bmask = 0x0000ff00;
amask = 0x000000ff;
#else
rmask = 0x000000ff;
gmask = 0x0000ff00;
bmask = 0x00ff0000;
amask = 0xff000000;
#endif
image = SDL_CreateRGBSurface(SDL_SWSURFACE, 720, 576, 0,
rmask, gmask, bmask, NULL);
if(image == NULL)
{
//fprintf(stderr, "CreateRGBSurface failed: %s\n", SDL_GetError());
exit(1);
}
//////////////////////////////////////////////////////////////////
while(av_read_frame(pFormatCtx, &packet)>=0)
{
// Is this a packet from the video stream?
if(packet.stream_index==videoStream)
{
// Decode video frame
avcodec_decode_video(pCodecCtx, pFrame, &frameFinished,
packet.data, packet.size);
// Did we get a video frame?
if(frameFinished)
{
// Convert the image from its native format to RGB
img_convert_ctx = sws_getContext( pCodecCtx->width,
pCodecCtx->height,
pCodecCtx->pix_fmt,
pCodecCtx->width,
pCodecCtx->height,
PIX_FMT_BGR24,
sws_flags, NULL, NULL, NULL);
sws_scale(img_convert_ctx,pFrame->data,pFrame->linesize,0,pCodecCtx->height,pFrameRGB->data,pFrameRGB->linesize);
sws_freeContext(img_convert_ctx);
////////////////////////////////////////////////////////////////
memcpy(screen->pixels,buffer,720*576*3);
SDL_UpdateRect(screen, 0, 0, image->w, image->h);
/* Free the allocated BMP surface */
SDL_FreeSurface(image);
/////////////////////////////////////////////////////////////////
// Save the frame to disk
if((++i<=5))
SaveFrame(pFrameRGB, pCodecCtx->width, pCodecCtx->height, i);
}
}
// Free the packet that was allocated by av_read_frame
av_free_packet(&packet);
}
// Free the RGB image
av_free(buffer);
av_free(pFrameRGB);
// Free the YUV frame
av_free(pFrame);
// Close the codec
avcodec_close(pCodecCtx);
// Close the video file
av_close_input_file(pFormatCtx);
MessageBox("over");
}
void CTest0Dlg::OnButton3()
{
// TODO: Add your control notification handler code here
// TODO: Add your control notification handler code here
AVFormatContext *pFormatCtx;
int i, videoStream;
AVCodecContext *pCodecCtx;
AVCodec *pCodec;
AVFrame *pFrame;
AVFrame *pFrameYUV;
AVPacket packet;
int frameFinished;
int numBytes;
uint8_t *buffer;
SDL_Rect rect;
static int sws_flags = SWS_BICUBIC;
struct SwsContext *img_convert_ctx;
AVPicture pict;
// argc = 2;
char argv[100] = "d:\\temp\\VIDEO720576.264";
// argv[1] = "d:\\temp\\ff.mpg";
// /*注册所有可用的格式和编解码器*/
av_register_all();
// Open video file /*以输入方式打开一个媒体文件,也即源文件,codecs并没有打开,只读取了文件的头信息*/
if(av_open_input_file(&pFormatCtx, argv, NULL, 0, NULL)!=0)
return ; // Couldn't open file
// Retrieve stream information
/*通过读取媒体文件的中的包来获取媒体文件中的流信息,对于没有头信息的文件如(mpeg)是非常有用的,
// 该函数通常重算类似mpeg-2帧模式的真实帧率,该函数并未改变逻辑文件的position.
*/
if(av_find_stream_info(pFormatCtx)<0)
return ; // Couldn't find stream information
// Dump information about file onto standard error
//该函数的作用就是检查下初始化过程中设置的参数是否符合规范
dump_format(pFormatCtx, 0, argv, 0);
// Find the first video stream
videoStream=-1;
printf("%d\n",pFormatCtx->nb_streams);
getchar();
for(i=0; i<pFormatCtx->nb_streams; i++)
if(pFormatCtx->streams[i]->codec->codec_type==CODEC_TYPE_VIDEO&&videoStream < 0)
{
videoStream=i;
break;
}
if(videoStream==-1)
return ; // Didn't find a video stream
// Get a pointer to the codec context for the video stream
pCodecCtx=pFormatCtx->streams[videoStream]->codec;
// Find the decoder for the video stream
pCodec=avcodec_find_decoder(pCodecCtx->codec_id);
/*通过code ID查找一个已经注册的音视频编码器,查找编码器之前,必须先调用av_register_all注册所有支持的编码器
音视频编码器保存在一个链表中,查找过程中,函数从头到尾遍历链表,通过比较编码器的ID来查找
*/
if(pCodec==NULL) {
fprintf(stderr, "Unsupported codec!\n");
return ; // Codec not found
}
// Open codec
//使用给定的AVCodec初始化AVCodecContext
if(avcodec_open(pCodecCtx, pCodec)<0)
return ; // Could not open codec
//printf("name %s\n",pCodec->name);
//getchar();
// Allocate video frame
pFrame=avcodec_alloc_frame();
// Allocate an AVFrame structure
pFrameYUV=avcodec_alloc_frame();
if(pFrameYUV==NULL)
return ;
// Determine required buffer size and allocate buffer
numBytes=avpicture_get_size(PIX_FMT_YUV420P, pCodecCtx->width,
pCodecCtx->height);
buffer=(uint8_t *)av_malloc(numBytes*sizeof(uint8_t));
// Assign appropriate parts of buffer to image planes in pFrameRGB
// Note that pFrameRGB is an AVFrame, but AVFrame is a superset
// of AVPicture
avpicture_fill((AVPicture *)pFrameYUV, buffer, PIX_FMT_YUV420P,
pCodecCtx->width, pCodecCtx->height);
// Read frames and save first five frames to disk
i=0;
////////////////////////////////////////////////////////////////
if (SDL_Init(SDL_INIT_VIDEO) < 0)
{
fprintf(stderr, "can not initialize SDL:%s\n", SDL_GetError());
exit(1);
}
atexit(SDL_Quit);
SDL_Surface *screen;
screen = SDL_SetVideoMode(720, 576, 24, SDL_SWSURFACE|SDL_ANYFORMAT);
if ( screen == NULL )
{
exit(2);
}
SDL_Overlay *image;
image = SDL_CreateYUVOverlay(pCodecCtx->width,
pCodecCtx->height,
SDL_YV12_OVERLAY,
screen);
if(image == NULL)
{
//fprintf(stderr, "CreateRGBSurface failed: %s\n", SDL_GetError());
exit(1);
}
//////////////////////////////////////////////////////////////////
while(av_read_frame(pFormatCtx, &packet)>=0)
{
// Is this a packet from the video stream?
if(packet.stream_index==videoStream)
{
// Decode video frame
avcodec_decode_video(pCodecCtx, pFrame, &frameFinished,
packet.data, packet.size);
// Did we get a video frame?
if(frameFinished)
{
// Convert the image from its native format to RGB
SDL_LockYUVOverlay(image);
// pFrameYUV->data[0] = image->pixels[0];//预先改变指针数据区，不用copy
// pFrameYUV->data[1] = image->pixels[2];
// pFrameYUV->data[2] = image->pixels[1];
//
// pFrameYUV->linesize[0] = image->pitches[0];
// pFrameYUV->linesize[1] = image->pitches[2];
// pFrameYUV->linesize[2] = image->pitches[1];
img_convert_ctx = sws_getContext( pCodecCtx->width,
pCodecCtx->height,
pCodecCtx->pix_fmt,
pCodecCtx->width,
pCodecCtx->height,
PIX_FMT_YUV420P,
sws_flags, NULL, NULL, NULL);
sws_scale(img_convert_ctx,pFrame->data,pFrame->linesize,0,pCodecCtx->height,pFrameYUV->data,pFrameYUV->linesize);
sws_freeContext(img_convert_ctx);
memcpy(image->pixels[0], pFrameYUV->data[0],720*576);//拷贝数据yuv420，也可预先改变指针
memcpy(image->pixels[2], pFrameYUV->data[1],720*576/4);
memcpy(image->pixels[1], pFrameYUV->data[2],720*576/4);
SDL_UnlockYUVOverlay(image);
rect.x = 0;
rect.y = 0;
rect.w = pCodecCtx->width;
rect.h = pCodecCtx->height;
SDL_DisplayYUVOverlay(image, &rect);
}
}
// Free the packet that was allocated by av_read_frame
av_free_packet(&packet);
}
// Free the RGB image
av_free(buffer);
av_free(pFrameYUV);
// Free the YUV frame
av_free(pFrame);
// Close the codec
avcodec_close(pCodecCtx);
// Close the video file
av_close_input_file(pFormatCtx);
MessageBox("over");
}
void CTest0Dlg::OnButton4()
{
// TODO: Add your control notification handler code here
// TODO: Add your control notification handler code here
AVFormatContext *pFormatCtx;
int i, videoStream;
AVCodecContext *pCodecCtx;
AVCodec *pCodec;
AVFrame *pFrame;
AVFrame *pFrameYUV;
AVPacket packet;
int frameFinished;
int numBytes;
uint8_t *buffer;
SDL_Rect rect;
static int sws_flags = SWS_BICUBIC;
struct SwsContext *img_convert_ctx;
AVPicture pict;
// argc = 2;
char argv[100] = "d:\\temp\\VIDEO720576.264";
// argv[1] = "d:\\temp\\ff.mpg";
// /*注册所有可用的格式和编解码器*/
av_register_all();
// Open video file /*以输入方式打开一个媒体文件,也即源文件,codecs并没有打开,只读取了文件的头信息*/
if(av_open_input_file(&pFormatCtx, argv, NULL, 0, NULL)!=0)
return ; // Couldn't open file
// Retrieve stream information
/*通过读取媒体文件的中的包来获取媒体文件中的流信息,对于没有头信息的文件如(mpeg)是非常有用的,
// 该函数通常重算类似mpeg-2帧模式的真实帧率,该函数并未改变逻辑文件的position.
*/
if(av_find_stream_info(pFormatCtx)<0)
return ; // Couldn't find stream information
// Dump information about file onto standard error
//该函数的作用就是检查下初始化过程中设置的参数是否符合规范
dump_format(pFormatCtx, 0, argv, 0);
// Find the first video stream
videoStream=-1;
printf("%d\n",pFormatCtx->nb_streams);
getchar();
for(i=0; i<pFormatCtx->nb_streams; i++)
if(pFormatCtx->streams[i]->codec->codec_type==CODEC_TYPE_VIDEO&&videoStream < 0)
{
videoStream=i;
break;
}
if(videoStream==-1)
return ; // Didn't find a video stream
// Get a pointer to the codec context for the video stream
pCodecCtx=pFormatCtx->streams[videoStream]->codec;
// Find the decoder for the video stream
pCodec=avcodec_find_decoder(pCodecCtx->codec_id);
/*通过code ID查找一个已经注册的音视频编码器,查找编码器之前,必须先调用av_register_all注册所有支持的编码器
音视频编码器保存在一个链表中,查找过程中,函数从头到尾遍历链表,通过比较编码器的ID来查找
*/
if(pCodec==NULL) {
fprintf(stderr, "Unsupported codec!\n");
return ; // Codec not found
}
// Open codec
//使用给定的AVCodec初始化AVCodecContext
if(avcodec_open(pCodecCtx, pCodec)<0)
return ; // Could not open codec
//printf("name %s\n",pCodec->name);
//getchar();
// Allocate video frame
pFrame=avcodec_alloc_frame();
// Allocate an AVFrame structure
pFrameYUV=avcodec_alloc_frame();
if(pFrameYUV==NULL)
return ;
// Determine required buffer size and allocate buffer
numBytes=avpicture_get_size(PIX_FMT_YUV422, pCodecCtx->width,
pCodecCtx->height);
buffer=(uint8_t *)av_malloc(numBytes*sizeof(uint8_t));
// Assign appropriate parts of buffer to image planes in pFrameRGB
// Note that pFrameRGB is an AVFrame, but AVFrame is a superset
// of AVPicture
avpicture_fill((AVPicture *)pFrameYUV, buffer, PIX_FMT_YUV422,
pCodecCtx->width, pCodecCtx->height);
// Read frames and save first five frames to disk
i=0;
////////////////////////////////////////////////////////////////
if (SDL_Init(SDL_INIT_VIDEO) < 0)
{
fprintf(stderr, "can not initialize SDL:%s\n", SDL_GetError());
exit(1);
}
atexit(SDL_Quit);
SDL_Surface *screen;
screen = SDL_SetVideoMode(720, 576, 24, SDL_SWSURFACE|SDL_ANYFORMAT);
if ( screen == NULL )
{
exit(2);
}
SDL_Overlay *image;
image = SDL_CreateYUVOverlay(pCodecCtx->width,
pCodecCtx->height,
SDL_YUY2_OVERLAY,
screen);
if(image == NULL)
{
//fprintf(stderr, "CreateRGBSurface failed: %s\n", SDL_GetError());
exit(1);
}
//////////////////////////////////////////////////////////////////
while(av_read_frame(pFormatCtx, &packet)>=0)
{
// Is this a packet from the video stream?
if(packet.stream_index==videoStream)
{
// Decode video frame
avcodec_decode_video(pCodecCtx, pFrame, &frameFinished,
packet.data, packet.size);
// Did we get a video frame?
if(frameFinished)
{
// Convert the image from its native format to RGB
SDL_LockYUVOverlay(image);
// pFrameYUV->data[0] = image->pixels[0];
// pFrameYUV->data[1] = image->pixels[2];
// pFrameYUV->data[2] = image->pixels[1];
//
// pFrameYUV->linesize[0] = image->pitches[0];
// pFrameYUV->linesize[1] = image->pitches[2];
// pFrameYUV->linesize[2] = image->pitches[1];
img_convert_ctx = sws_getContext( pCodecCtx->width,
pCodecCtx->height,
pCodecCtx->pix_fmt,
pCodecCtx->width,
pCodecCtx->height,
PIX_FMT_YUV422,
sws_flags, NULL, NULL, NULL);
sws_scale(img_convert_ctx,pFrame->data,pFrame->linesize,0,pCodecCtx->height,pFrameYUV->data,pFrameYUV->linesize);
sws_freeContext(img_convert_ctx);
memcpy(image->pixels[0], pFrameYUV->data[0],720*576*2);//拷贝数据yuv422
SDL_UnlockYUVOverlay(image);
rect.x = 0;
rect.y = 0;
rect.w = pCodecCtx->width;
rect.h = pCodecCtx->height;
SDL_DisplayYUVOverlay(image, &rect);
}
}
// Free the packet that was allocated by av_read_frame
av_free_packet(&packet);
}
// Free the RGB image
av_free(buffer);
av_free(pFrameYUV);
// Free the YUV frame
av_free(pFrame);
// Close the codec
avcodec_close(pCodecCtx);
// Close the video file
av_close_input_file(pFormatCtx);
MessageBox("over");
}
http://download.csdn.net/detail/mao0514/8202691
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