(SDL)一个简单的SDL视频文件播放程序

Posted 2020-12-29 aperolchen

需要说明的是，对于新手需要在ubuntu系统安装SDL库安装包和开发安装包，可以参考官网的文章：

https://wiki.libsdl.org/Installation

SDL是跨平台的，下面的代码更改下#include路径，指引下连接lib库，就可以在windows上编译运行。

文章旨在快速运行一个example，具体SDL API需查看官方文档。

  1 #include "iostream"
  2 #include "SDL2/SDL.h"
  3 
  4 #define PIXEL_W 352
  5 #define PIXEL_H 288
  6 #define IMAGE_SIZE 152064 // 352 * 288 * 1.5
  7 
  8 #define REFRESH_EVENT (SDL_USEREVENT + 1) // 自定义事件，每40毫秒触发图像帧更新
  9 
 10 bool thread_exit = false;
 11 // 每40毫秒出发图像帧更新
 12 int refresh_video(void *opaque)
 13 {
 14     while (thread_exit == false)
 15     {
 16         SDL_Event event;
 17         event.type = REFRESH_EVENT;
 18         SDL_PushEvent(&event);
 19         std::cout << "push REFRESH_EVENT" << std::endl;
 20         SDL_Delay(40);
 21     }
 22 
 23     return 0;
 24 }
 25 
 26 int main(int argc, char **argv)
 27 {
 28     if (SDL_Init(SDL_INIT_VIDEO) == -1)
 29     {
 30         std::cout << SDL_GetError() << std::endl;
 31         return -1;
 32     }
 33 
 34     SDL_Window *sdlWindow = NULL;
 35     sdlWindow= SDL_CreateWindow("SDL example", SDL_WINDOWPOS_UNDEFINED, SDL_WINDOWPOS_UNDEFINED, PIXEL_W, PIXEL_H, SDL_WINDOW_OPENGL);
 36     if (sdlWindow == NULL)
 37     {
 38         std::cout << SDL_GetError() << std::endl;
 39         return -1;
 40     }
 41 
 42     SDL_Renderer *sdlRenderer = NULL;
 43     sdlRenderer = SDL_CreateRenderer(sdlWindow, -1, SDL_RENDERER_ACCELERATED | SDL_RENDERER_PRESENTVSYNC);
 44     if (sdlRenderer == NULL)
 45     {
 46         std::cout << SDL_GetError() << std::endl;
 47         return -1;
 48     }
 49 
 50     SDL_Texture *sdlTexture = SDL_CreateTexture(sdlRenderer, SDL_PIXELFORMAT_IYUV, SDL_TEXTUREACCESS_STREAMING, PIXEL_W, PIXEL_H);
 51 
 52     FILE *fp = fopen("352_288_example.IYUV", "r");
 53     if (fp == NULL)
 54     {
 55         std::cout << "open file error" << std::endl;
 56         return -1;
 57     }
 58 
 59     char *pImageBuffer = (char *)malloc(IMAGE_SIZE);
 60     if (pImageBuffer == NULL)
 61     {
 62         std::cout << "malloc image buffer error" << std::endl;
 63         return -1;
 64     }
 65 
 66     memset(pImageBuffer, 0x00, IMAGE_SIZE);
 67 
 68     SDL_Rect sdlRect;
 69     sdlRect.x = 0;
 70     sdlRect.y = 0;
 71     sdlRect.w = PIXEL_W;
 72     sdlRect.h = PIXEL_H;
 73 
 74     SDL_Event event;
 75     SDL_Thread *refresh_thread = SDL_CreateThread(refresh_video, NULL, NULL);
 76 
 77     while(1)
 78     {
 79         std::cout << "waiting event..." << std::endl;
 80         SDL_WaitEvent(&event);
 81         if (event.type == REFRESH_EVENT)
 82         {
 83             std::cout << "get REFRESH_EVENT." << std::endl;
 84             if (fread(pImageBuffer, 1, IMAGE_SIZE, fp) != IMAGE_SIZE)
 85             {
 86                 fseek(fp, 0, SEEK_SET);
 87                 fread(pImageBuffer, 1, IMAGE_SIZE, fp);
 88             }
 89 
 90             SDL_UpdateTexture(sdlTexture, NULL, pImageBuffer, PIXEL_W);
 91             SDL_RenderClear(sdlRenderer);
 92             SDL_RenderCopy(sdlRenderer, sdlTexture, NULL, &sdlRect);
 93             SDL_RenderPresent(sdlRenderer);
 94         }
 95         else if (event.type == SDL_QUIT)
 96         {
 97             std::cout << "get QUIT." << std::endl;
 98             break;
 99         }
100         else
101         {
102             std::cout << event.type << std::endl;
103         }
104     }
105 
106     thread_exit = true;
107     return 0;
108 }

sample所用的视频文件可以在这里下载：

 https://pan.baidu.com/s/1LyxdBEO3kFi3bLzVnyKJQw