FFmpeg+SDL的视频播放器的制作（4）

FFmpeg &＃43; SDL的视频播放器的制作&＃xff08;4&＃xff09;

SDL的函数和数据结构

二倍速度

二倍宽度

窗口大小固定为500X500

视频周围包围10像素的“黑框”

换一段测试YUV素材进行播放

示例程序&＃xff1a;

/*** 最简单的SDL2播放视频的例子&＃xff08;SDL2播放RGB/YUV&＃xff09;* Simplest Video Play SDL2 (SDL2 play RGB/YUV) ** 雷霄骅 Lei Xiaohua* leixiaohua1020&＃64;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&＃xff08;Direct3D&＃xff0c;OpenGL&＃xff09;的封装&＃xff0c;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 extern "C"
{
#include "sdl/SDL.h"
};const int bpp&＃61;12;//原窗口为320*180
int screen_w&＃61;500,screen_h&＃61;500;
const int pixel_w&＃61;640,pixel_h&＃61;360;//YUV数据的宽高unsigned char buffer[pixel_w*pixel_h*bpp/8];int main(int argc, char* argv[])
{if(SDL_Init(SDL_INIT_VIDEO)) { //初始化SDL系统printf( "Could not initialize SDL - %s\n", SDL_GetError()); return -1;} SDL_Window *screen; //代表了一个窗口//SDL 2.0 Support for multiple windowsscreen &＃61; SDL_CreateWindow("Simplest Video Play SDL2", SDL_WINDOWPOS_UNDEFINED, SDL_WINDOWPOS_UNDEFINED,screen_w, screen_h,SDL_WINDOW_OPENGL|SDL_WINDOW_RESIZABLE);//创建窗口SDL_Window&＃xff0c;指定窗口的宽screen_w和高screen_hif(!screen) { printf("SDL: could not create window - exiting:%s\n",SDL_GetError()); return -1;}SDL_Renderer* sdlRenderer &＃61; SDL_CreateRenderer(screen, -1, 0); //创建渲染器SDL_RendererUint32 pixformat&＃61;0;//IYUV: Y &＃43; U &＃43; V (3 planes)//YV12: Y &＃43; V &＃43; U (3 planes)pixformat&＃61; SDL_PIXELFORMAT_IYUV; SDL_Texture* sdlTexture &＃61; SDL_CreateTexture(sdlRenderer,pixformat, SDL_TEXTUREACCESS_STREAMING,pixel_w,pixel_h);//创建纹理SDL_TextureFILE *fp&＃61;NULL;fp&＃61;fopen("sintel_640_360.yuv","rb&＃43;");//打开YUV文件if(fp&＃61;&＃61;NULL){printf("cannot open this file\n");return -1;}SDL_Rect sdlRect; //一个简单的矩形结构&＃xff0c;决定图形显示屏幕在什么位置上while(1){//bpp&＃xff0c;每个像素占多少比特&＃xff0c;pixel_w*pixel_h*bpp/8这是读取一帧完整的YUV数据//Y数据量&＃xff1a;宽*高&＃xff0c;U和V的数据量是宽*高/4&＃xff0c;1&＃43;1/4&＃43;1/4&＃61;1.5if (fread(buffer, 1, pixel_w*pixel_h*bpp/8, fp) !&＃61; pixel_w*pixel_h*bpp/8){//读一帧YUV数据到buffer里面// Loopfseek(fp, 0, SEEK_SET);fread(buffer, 1, pixel_w*pixel_h*bpp/8, fp);}SDL_UpdateTexture( sdlTexture, NULL, buffer, pixel_w); //设置或更新纹理的数据&＃xff0c;YUV数据传递给了SDL_UpdateTexture//sdlRect的x和y是矩形左上角点的坐标(全屏显示&＃xff08;0&＃xff0c;0&＃xff09;)//x&＃xff0c;y相当于起始点//视频周围包围10像素的黑边&＃xff0c;所以x&＃xff0c;y为10sdlRect.x &＃61; 10; sdlRect.y &＃61; 10; sdlRect.w &＃61; screen_w-20; //矩形两边&＃xff0c;所以减20sdlRect.h &＃61; screen_h-20; SDL_RenderClear( sdlRenderer ); SDL_RenderCopy( sdlRenderer, sdlTexture, NULL, &sdlRect); //将纹理的数据拷贝给渲染器SDL_RenderPresent( sdlRenderer ); //显示&＃xff0c;渲染器把纹理渲染出来到窗口中//Delay 40ms//显示视频&＃xff0c;每秒显示25帧SDL_Delay(20);//延时40ms&＃xff08;25帧&＃xff09;。2倍的速度&＃xff0c;除以2&＃xff0c;改成20}SDL_Quit();//退出SDL系统return 0;
}