本文补充记录《最简单的基于FFMPEG+SDL的视频播放器》中的两个例子：FFmpeg视频解码器和SDL像素数据播放器。这两个部分是从视频播放器中拆分出来的两个例子。FFmpeg视频解码器实现了视频数据到YUV数据的解码，而SDL像素数据播放器实现了YUV数据的显示。简而言之，原先的FFmpeg+SDL视频播放器实现了：
视频数据->YUV->显示器
FFmpeg视频解码器实现了：
视频数据->YUV
SDL像素数据播放器实现了：
/**
* 最简单的基于FFmpeg的视频解码器
* Simplest FFmpeg Decoder
*
* 雷霄骅 Lei Xiaohua
* leixiaohua1020@126.com
* 中国传媒大学/数字电视技术
* Communication University of China / Digital TV Technology
* http://blog.csdn.net/leixiaohua1020
*
*
* 本程序实现了视频文件解码为YUV数据。它使用了libavcodec和
* libavformat。是最简单的FFmpeg视频解码方面的教程。
* 通过学习本例子可以了解FFmpeg的解码流程。
* This software is a simplest decoder based on FFmpeg.
* It decodes video to YUV pixel data.
* It uses libavcodec and libavformat.
* Suitable for beginner of FFmpeg.
*
*/
#include <stdio.h>
#define __STDC_CONSTANT_MACROS
#ifdef _WIN32
//Windows
extern "C"
{
#include "libavcodec/avcodec.h"
#include "libavformat/avformat.h"
#include "libswscale/swscale.h"
};
#else
//Linux...
#ifdef __cplusplus
extern "C"
{
#endif
#include <libavcodec/avcodec.h>
#include <libavformat/avformat.h>
#include <libswscale/swscale.h>
#ifdef __cplusplus
};
#endif
#endif
int main(int argc, char* argv[])
{
AVFormatContext *pFormatCtx;
int i, videoindex;
AVCodecContext *pCodecCtx;
AVCodec *pCodec;
AVFrame *pFrame,*pFrameYUV;
uint8_t *out_buffer;
AVPacket *packet;
int y_size;
int ret, got_picture;
struct SwsContext *img_convert_ctx;
char filepath[]="Titanic.mkv";
FILE *fp_yuv=fopen("output.yuv","wb+");
av_register_all();
avformat_network_init();
pFormatCtx = avformat_alloc_context();
if(avformat_open_input(&pFormatCtx,filepath,NULL,NULL)!=0){
printf("Couldn‘t open input stream.\n");
return -1;
}
if(avformat_find_stream_info(pFormatCtx,NULL)<0){
printf("Couldn‘t find stream information.\n");
return -1;
}
videoindex=-1;
for(i=0; i<pFormatCtx->nb_streams; i++)
if(pFormatCtx->streams[i]->codec->codec_type==AVMEDIA_TYPE_VIDEO){
videoindex=i;
break;
}
if(videoindex==-1){
printf("Didn‘t find a video stream.\n");
return -1;
}
pCodecCtx=pFormatCtx->streams[videoindex]->codec;
pCodec=avcodec_find_decoder(pCodecCtx->codec_id);
if(pCodec==NULL){
printf("Codec not found.\n");
return -1;
}
if(avcodec_open2(pCodecCtx, pCodec,NULL)<0){
printf("Could not open codec.\n");
return -1;
}
pFrame=av_frame_alloc();
pFrameYUV=av_frame_alloc();
out_buffer=(uint8_t *)av_malloc(avpicture_get_size(PIX_FMT_YUV420P, pCodecCtx->width, pCodecCtx->height));
avpicture_fill((AVPicture *)pFrameYUV, out_buffer, PIX_FMT_YUV420P, pCodecCtx->width, pCodecCtx->height);
packet=(AVPacket *)av_malloc(sizeof(AVPacket));
//Output Info-----------------------------
printf("--------------- File Information ----------------\n");
av_dump_format(pFormatCtx,0,filepath,0);
printf("-------------------------------------------------\n");
img_convert_ctx = sws_getContext(pCodecCtx->width, pCodecCtx->height, pCodecCtx->pix_fmt,
pCodecCtx->width, pCodecCtx->height, PIX_FMT_YUV420P, SWS_BICUBIC, NULL, NULL, NULL);
while(av_read_frame(pFormatCtx, packet)>=0){
if(packet->stream_index==videoindex){
ret = avcodec_decode_video2(pCodecCtx, pFrame, &got_picture, packet);
if(ret < 0){
printf("Decode Error.\n");
return -1;
}
if(got_picture){
sws_scale(img_convert_ctx, (const uint8_t* const*)pFrame->data, pFrame->linesize, 0, pCodecCtx->height,
pFrameYUV->data, pFrameYUV->linesize);
y_size=pCodecCtx->width*pCodecCtx->height;
fwrite(pFrameYUV->data[0],1,y_size,fp_yuv); //Y
fwrite(pFrameYUV->data[1],1,y_size/4,fp_yuv); //U
fwrite(pFrameYUV->data[2],1,y_size/4,fp_yuv); //V
printf("Succeed to decode 1 frame!\n");
}
}
av_free_packet(packet);
}
//flush decoder
//FIX: Flush Frames remained in Codec
while (1) {
ret = avcodec_decode_video2(pCodecCtx, pFrame, &got_picture, packet);
if (ret < 0)
break;
if (!got_picture)
break;
sws_scale(img_convert_ctx, (const uint8_t* const*)pFrame->data, pFrame->linesize, 0, pCodecCtx->height,
pFrameYUV->data, pFrameYUV->linesize);
int y_size=pCodecCtx->width*pCodecCtx->height;
fwrite(pFrameYUV->data[0],1,y_size,fp_yuv); //Y
fwrite(pFrameYUV->data[1],1,y_size/4,fp_yuv); //U
fwrite(pFrameYUV->data[2],1,y_size/4,fp_yuv); //V
printf("Flush Decoder: Succeed to decode 1 frame!\n");
}
sws_freeContext(img_convert_ctx);
fclose(fp_yuv);
av_frame_free(&pFrameYUV);
av_frame_free(&pFrame);
avcodec_close(pCodecCtx);
avformat_close_input(&pFormatCtx);
return 0;
}
/**
* 最简单的SDL2播放视频的例子（SDL2播放RGB/YUV）
* Simplest Video Play SDL2 (SDL2 play RGB/YUV)
*
* 雷霄骅 Lei Xiaohua
* leixiaohua1020@126.com
* 中国传媒大学/数字电视技术
* Communication University of China / Digital TV Technology
* http://blog.csdn.net/leixiaohua1020
*
* 本程序使用SDL2播放RGB/YUV视频像素数据。SDL实际上是对底层绘图
* API（Direct3D，OpenGL）的封装，使用起来明显简单于直接调用底层
* API。
*
* 函数调用步骤如下:
*
* [初始化]
* SDL_Init(): 初始化SDL。
* SDL_CreateWindow(): 创建窗口（Window）。
* SDL_CreateRenderer(): 基于窗口创建渲染器（Render）。
* SDL_CreateTexture(): 创建纹理（Texture）。
*
* [循环渲染数据]
* SDL_UpdateTexture(): 设置纹理的数据。
* SDL_RenderCopy(): 纹理复制给渲染器。
* SDL_RenderPresent(): 显示。
*
* This software plays RGB/YUV raw video data using SDL2.
* SDL is a wrapper of low-level API (Direct3D, OpenGL).
* Use SDL is much easier than directly call these low-level API.
*
* The process is shown as follows:
*
* [Init]
* SDL_Init(): Init SDL.
* SDL_CreateWindow(): Create a Window.
* SDL_CreateRenderer(): Create a Render.
* SDL_CreateTexture(): Create a Texture.
*
* [Loop to Render data]
* SDL_UpdateTexture(): Set Texture‘s data.
* SDL_RenderCopy(): Copy Texture to Render.
* SDL_RenderPresent(): Show.
*/
#include <stdio.h>
extern "C"
{
#include "sdl/SDL.h"
};
const int bpp=12;
int screen_w=500,screen_h=500;
const int pixel_w=320,pixel_h=180;
unsigned char buffer[pixel_w*pixel_h*bpp/8];
//Refresh Event
#define REFRESH_EVENT (SDL_USEREVENT + 1)
#define BREAK_EVENT (SDL_USEREVENT + 2)
int thread_exit=0;
int refresh_video(void *opaque){
thread_exit=0;
while (!thread_exit) {
SDL_Event event;
event.type = REFRESH_EVENT;
SDL_PushEvent(&event);
SDL_Delay(40);
}
thread_exit=0;
//Break
SDL_Event event;
event.type = BREAK_EVENT;
SDL_PushEvent(&event);
return 0;
}
int main(int argc, char* argv[])
{
if(SDL_Init(SDL_INIT_VIDEO)) {
printf( "Could not initialize SDL - %s\n", SDL_GetError());
return -1;
}
SDL_Window *screen;
//SDL 2.0 Support for multiple windows
screen = SDL_CreateWindow("Simplest Video Play SDL2", SDL_WINDOWPOS_UNDEFINED, SDL_WINDOWPOS_UNDEFINED,
screen_w, screen_h,SDL_WINDOW_OPENGL|SDL_WINDOW_RESIZABLE);
if(!screen) {
printf("SDL: could not create window - exiting:%s\n",SDL_GetError());
return -1;
}
SDL_Renderer* sdlRenderer = SDL_CreateRenderer(screen, -1, 0);
Uint32 pixformat=0;
//IYUV: Y + U + V (3 planes)
//YV12: Y + V + U (3 planes)
pixformat= SDL_PIXELFORMAT_IYUV;
SDL_Texture* sdlTexture = SDL_CreateTexture(sdlRenderer,pixformat, SDL_TEXTUREACCESS_STREAMING,pixel_w,pixel_h);
FILE *fp=NULL;
fp=fopen("test_yuv420p_320x180.yuv","rb+");
if(fp==NULL){
printf("cannot open this file\n");
return -1;
}
SDL_Rect sdlRect;
SDL_Thread *refresh_thread = SDL_CreateThread(refresh_video,NULL,NULL);
SDL_Event event;
while(1){
//Wait
SDL_WaitEvent(&event);
if(event.type==REFRESH_EVENT){
if (fread(buffer, 1, pixel_w*pixel_h*bpp/8, fp) != pixel_w*pixel_h*bpp/8){
// Loop
fseek(fp, 0, SEEK_SET);
fread(buffer, 1, pixel_w*pixel_h*bpp/8, fp);
}
SDL_UpdateTexture( sdlTexture, NULL, buffer, pixel_w);
//FIX: If window is resize
sdlRect.x = 0;
sdlRect.y = 0;
sdlRect.w = screen_w;
sdlRect.h = screen_h;
SDL_RenderClear( sdlRenderer );
SDL_RenderCopy( sdlRenderer, sdlTexture, NULL, &sdlRect);
SDL_RenderPresent( sdlRenderer );
}else if(event.type==SDL_WINDOWEVENT){
//If Resize
SDL_GetWindowSize(screen,&screen_w,&screen_h);
}else if(event.type==SDL_QUIT){
thread_exit=1;
}else if(event.type==BREAK_EVENT){
break;
}
}
SDL_Quit();
return 0;
}
项目主页
SourceForge：https://sourceforge.net/projects/simplestffmpegplayer/Github：https://github.com/leixiaohua1020/simplest_ffmpeg_player
开源中国：http://git.oschina.net/leixiaohua1020/simplest_ffmpeg_player
simplest_ffmpeg_player：标准版，FFmpeg学习的开始。
simplest_ffmpeg_player_su：SU（SDL Update）版，加入了简单的SDL的Event。
simplest_ffmpeg_decoder：一个包含了封装格式处理功能的解码器。使用了libavcodec和libavformat。
simplest_ffmpeg_decoder_pure：一个纯净的解码器。只使用libavcodec（没有使用libavformat）。
simplest_video_play_sdl2：使用SDL2播放YUV的例子。
simplest_ffmpeg_helloworld：输出FFmpeg类库的信息。
版权声明：本文为博主原创文章，未经博主允许不得转载。
最简单的基于FFMPEG+SDL的视频播放器：拆分-解码器和播放器
原文地址：http://blog.csdn.net/leixiaohua1020/article/details/46889389
