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#include <stdio.h>
extern "C"
{
#include "SDL2/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];
// SDL_USEREVENT是SDL库中预定义的一个用户事件起始值
// 刷新事件
#define REFRESH_EVENT (SDL_USEREVENT + 1)
// 中断事件
#define BREAK_EVENT (SDL_USEREVENT + 2)
// 线程退出标志
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;
// 推送一个退出主线程的事件
SDL_Event event;
event.type = BREAK_EVENT;
SDL_PushEvent(&event);
return 0;
}
int main(int argc, char *argv[])
{
// 初始化 SDL 库
if (SDL_Init(SDL_INIT_VIDEO))
{
printf("Could not initialize SDL - %s\n", SDL_GetError());
return -1;
}
// 创建一个窗口
SDL_Window *screen;
// SDL 2.0 Support for multiple windows
screen =
SDL_CreateWindow("Simplest Video Play SDL2", SDL_WINDOWPOS_CENTERED, SDL_WINDOWPOS_CENTERED,
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;
}
// 创建一个渲染器，将窗口与渲染器关联
SDL_Renderer *sdlRenderer = SDL_CreateRenderer(screen, -1, 0);
Uint32 pixformat = 0;
// IYUV: Y + U + V (3 planes)
// YV12: Y + V + U (3 planes)
// 设置像素格式
// SDL_PIXELFORMAT_IYUV 表示使用 YUV420
pixformat = SDL_PIXELFORMAT_IYUV;
// 创建纹理，用于存储视频数据
SDL_Texture *sdlTexture =
SDL_CreateTexture(sdlRenderer, pixformat, SDL_TEXTUREACCESS_STREAMING, pixel_w, pixel_h);
// 打开 YUV 文件
FILE *fp = NULL;
fp = fopen("../video/test_yuv420p_320x180.yuv", "rb+");
if (fp == NULL)
{
printf("cannot open this file\n");
return -1;
}
SDL_Rect sdlRect;
// 创建一个子线程，用于定时触发视频刷新事件
// 第一个参数是函数指针
SDL_Thread *refresh_thread = SDL_CreateThread(refresh_video, NULL, NULL);
SDL_Event event;
while (1)
{
// 等待事件
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)
{
// 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/2;
sdlRect.h = screen_h/2;
SDL_RenderClear(sdlRenderer);
SDL_RenderCopy(sdlRenderer, sdlTexture, NULL, &sdlRect);
SDL_RenderPresent(sdlRenderer);
}
// SDL_WINDOWEVENT 当窗口大小改变时，更新屏幕宽度和高度
else if (event.type == SDL_WINDOWEVENT)
{
// window
SDL_GetWindowSize(screen, &screen_w, &screen_h);
}
// 当用户关闭窗口时，设置退出标志使子线程退出
else if (event.type == SDL_QUIT)
{
thread_exit = 1;
}
// 当接收到退出事件时，退出主循环并释放资源
// 这个退出事件由子线程提供
else if (event.type == BREAK_EVENT)
{
break;
}
}
SDL_Quit();
return 0;
}
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