最简SDL显示视频实例

    本实例运行的前提是正确安装了SDL。SDL的安装可以参考：linux安装编译配置ffmpeg和SDL 

    本实例是运行在linux平台，由雷神在Windows的程序修改而成。test.c 的代码如下：

#include <stdio.h>
#include "SDL.h"

#define REFRESH_EVENT  (SDL_USEREVENT + 1)
#define BREAK_EVENT  (SDL_USEREVENT + 2)

#define BPP			12
#define SCREEN_W	500
#define SCREEN_H 	500
#define PIXEL_W	 	320
#define	PIXEL_H		180

const int bpp	=BPP;
int screen_w	=SCREEN_W;
int screen_h	=SCREEN_H;
const int pixel_w=PIXEL_W;
const int pixel_h=PIXEL_H;
unsigned char buffer[PIXEL_W*PIXEL_H*BPP/8];

int thread_exit=0;
int refresh_video(void *opaque){
thread_exit=0;
while (thread_exit==0) {
SDL_Event event;
event.type = REFRESH_EVENT;
/* 发送一个事件 */
SDL_PushEvent(&event);
SDL_Delay(40);
}
thread_exit=0;
//Break
SDL_Event event;
event.type = BREAK_EVENT;
/* 发送一个事件*/
SDL_PushEvent(&event);
return 0;
}

int main(int argc, char* argv[])
{
Uint32 pixformat=0;
FILE *fp=NULL;
SDL_Rect sdlRect;
SDL_Window *screen;
SDL_Event event;

/* 初始化SDL系统 */
if(SDL_Init(SDL_INIT_VIDEO)) {
printf( "Could not initialize SDL - %s\n", SDL_GetError());
return -1;
}

/* 创建窗口SDL_Window */
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);

//YV12: Y + V + U  (3 planes)
pixformat= SDL_PIXELFORMAT_IYUV;
/* 创建渲染器SDL_Renderer */
SDL_Texture* sdlTexture = SDL_CreateTexture(sdlRenderer,pixformat, SDL_TEXTUREACCESS_STREAMING,pixel_w,pixel_h);

fp=fopen("test_yuv420p_320x180.yuv","rb+");

if(fp==NULL){
printf("cannot open this file\n");
return -1;
}

/* 创建一个线程 */
SDL_Thread *refresh_thread = SDL_CreateThread(refresh_video,NULL,NULL);

while(1){
/* 等待一个事件 */
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){
fseek(fp, 0, SEEK_SET);
fread(buffer, 1, pixel_w*pixel_h*bpp/8, fp);
}

/* 设置纹理的数据 */
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 );
/* 将纹理的数据拷贝给渲染器 */
SDL_RenderCopy( sdlRenderer, sdlTexture, NULL, &sdlRect);
/* 显示 */
SDL_RenderPresent( sdlRenderer );

}else if(event.type==SDL_WINDOWEVENT){
/* 查询显示窗口大小 */
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;
}

Makefile文件书写如下：

OUT_APP      = test
INCLUDE_PATH = /usr/local/include/SDL2/
INCLUDE      = -I$(INCLUDE_PATH)

FFMPEG_LIBS =
SDL_LIBS    = -lSDL2 -lSDL2main -lSDL2_test
LIBS        = $(FFMPEG_LIBS)$(SDL_LIBS)

COMPILE_OPTS = $(INCLUDE)
C            = c
OBJ          = o
C_COMPILER   = cc
C_FLAGS      = $(COMPILE_OPTS) $(CPPFLAGS) $(CFLAGS)

LINK         = cc -o
LINK_OPTS    =
LINK_OBJ     = test.o

.$(C).$(OBJ):
$(C_COMPILER) -c $(C_FLAGS) $<

$(OUT_APP): $(LINK_OBJ)
$(LINK)$@  $(LINK_OBJ)  $(LIBS) $(LINK_OPTS)

clean:
-rm -rf *.$(OBJ) $(OUT_APP) core *.core *~ include/*~

    注意上面Makefile的头文件路径和SDL库文件的路径，应该与你安装SDL的路径相同。