最简单的SDL2播放视频的例子（SDL2播放RGB/YUV）--进阶

SDL中事件和多线程

SDL事件

SDL_WaitEvent()等待一个事件

        SDL_PushEvent（）发送一个事件

/**

 * 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。

 *

 * 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.  

 */

#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)

//Break

#define BREAK_EVENT  (SDL_USEREVENT + 2)

int thread_exit=0;

int refresh_video(void *opaque){
thread_exit=0;
while (thread_exit==0) {
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;

}