SDL教程(二)——Qt+SDL播放器

news2025/3/16 6:48:50

前言

这篇文章主要是使用SDL来打开视频，显示视频。后续会再继续使用SDL来结合FFmpeg。来能够直接使用网上的demo进行学习。

正文

一、环境

Qt 5.15.2 MSVC2019 64bit

Win11

二、Qt搭建SDL

Qt搭建，我觉得相比用VS2019来说，更为方便，至少你后面再新建一个项目的时候，很多代码直接拷过去就可以了，不用每次都去点属性页。确实，也可以在VS2019上搭建一个通用属性页，到哪里，就拷贝到哪，这倒也是一种方法。

1、肯定就是还是那些库，关于下载的可以去参考第一篇文章：SDL教程(一)——开发环境

2、Qt pro文件中引入：

INCLUDEPATH += $$PWD/../../SDL_Lib/include
LIBS += -L$$PWD/../../SDL_Lib/lib/x64 -lSDL2
LIBS += -L$$PWD/../../SDL_Lib/lib/x64 -lSDL2main

3、我待会直接打包上传到CSDN上，有需要的可以去下载，但一般来说，应该把这篇文章看完就好了，下载，只是说让你免去一些拷贝的步骤以及自己找一些文件罢了。
SDL显示yuv视频以及库文件都在里面
文件都在这里面

三、显示yuv文件

1、可以直接在MainWindow搞个函数来显示。

int MainWindow::ShowVideo()
{
    // yuv file
    FILE *fyuv;

    int srcW = 320;
    int srcH = 180;

    fopen_s(&fyuv, "frame_320x180_out.yuv", "rb");  // yuv420p
    char* buf = new char[srcW*srcH * 3 / 2];

    // SDL
    SDL_Window *window;
    SDL_Renderer *renderer;
    SDL_Texture *texture;
    SDL_Rect rect;
    SDL_Event event;

    int screen_w = srcW;
    int screen_h = srcH;

    window = SDL_CreateWindow("SDL2.0 Video Sample", SDL_WINDOWPOS_UNDEFINED, SDL_WINDOWPOS_UNDEFINED,
                              screen_w, screen_h, SDL_WINDOW_RESIZABLE);
    if(!window) {
        SDL_LogError(1, "SDL: SDL_CreateWindow failed.");
        return 0;
    }

    renderer = SDL_CreateRenderer(window, -1, 0);
    if(!renderer) {
        SDL_LogError(1, "SDL: SDL_CreateRenderer failed.");
        return 0;
    }

    texture = SDL_CreateTexture(renderer, SDL_PIXELFORMAT_IYUV,  //指定纹理为yuv420p
                                SDL_TextureAccess::SDL_TEXTUREACCESS_STREAMING, screen_w, screen_h);
    if(!texture) {
        SDL_LogError(1, "SDL: SDL_CreateTexture failed.");
        return 0;
    }

    rect = SDL_Rect{0,0,screen_w, screen_h};   // 尺寸需要与texture相同

    while(1)
    {
        if(fread(buf, srcW*srcH * 3 / 2, 1, fyuv) <= 0)
            break;

        SDL_UpdateTexture(texture, &rect, buf, srcW);  // YUV数据是连续的，1字节对齐

        SDL_RenderClear(renderer);
        SDL_RenderCopy(renderer, texture, NULL, &rect);
        SDL_RenderPresent(renderer);

        SDL_Delay(40);
    }

    free(buf);
    SDL_Quit();
}

2、效果

在这里插入图片描述

3、也可以直接将代码弄到main.cpp里面

#pragma comment( linker, "/subsystem:\"windows\" /entry:\"mainCRTStartup\"" )
#include <iostream>

#define SDL_MAIN_HANDLED
#include "SDL.h"

int main()
{
    // yuv file
    FILE *fyuv;

    int srcW = 320;
    int srcH = 180;

    fopen_s(&fyuv, "frame_320x180_out.yuv", "rb");  // yuv420p
    char* buf = new char[srcW*srcH * 3 / 2];

    // SDL
    SDL_Window *window;
    SDL_Renderer *renderer;
    SDL_Texture *texture;
    SDL_Rect rect;
    SDL_Event event;

    int screen_w = srcW;
    int screen_h = srcH;

    window = SDL_CreateWindow("SDL2.0 Video Sample", SDL_WINDOWPOS_UNDEFINED, SDL_WINDOWPOS_UNDEFINED,
                              screen_w, screen_h, SDL_WINDOW_RESIZABLE);
    if(!window) {
        SDL_LogError(1, "SDL: SDL_CreateWindow failed.");
        return 0;
    }

    renderer = SDL_CreateRenderer(window, -1, 0);
    if(!renderer) {
        SDL_LogError(1, "SDL: SDL_CreateRenderer failed.");
        return 0;
    }

    texture = SDL_CreateTexture(renderer, SDL_PIXELFORMAT_IYUV,  //指定纹理为yuv420p
                                SDL_TextureAccess::SDL_TEXTUREACCESS_STREAMING, screen_w, screen_h);
    if(!texture) {
        SDL_LogError(1, "SDL: SDL_CreateTexture failed.");
        return 0;
    }

    rect = SDL_Rect{0,0,screen_w, screen_h};   // 尺寸需要与texture相同

    while(1)
    {
        if(fread(buf, srcW*srcH * 3 / 2, 1, fyuv) <= 0)
            break;

        SDL_UpdateTexture(texture, &rect, buf, srcW);  // YUV数据是连续的，1字节对齐

        SDL_RenderClear(renderer);
        SDL_RenderCopy(renderer, texture, NULL, &rect);
        SDL_RenderPresent(renderer);

        SDL_Delay(40);
    }

    free(buf);
    SDL_Quit();
}