使用SDL2播放yuv文件，采用C++实现SDL2视频播放器

港控/mmm° 2022-01-10 15:43 335阅读 0赞

在[雷神][Link 1]的SDL2播放器基础上用C++将播放器封装成类，里面部分元素采用C++的相关语法，如使用shared\_ptr分配内存、async代替SDL的SDL\_CreateThread创建线程方法等。

使用样例：

SimpleSDLPlayer simpleSDLPlayer(352, 288, 176, 144, "SDL2 Player");
        simpleSDLPlayer.play("suzie_qcif.yuv");

--------------------

类代码如下：  
头文件：

#pragma once
    
    extern "C"
    {
    #include "SDL/SDL.h"
    }
    
    #include <stdio.h>
    #include <string>
    
    class SimpleSDLPlayer
    {
    public:
        SimpleSDLPlayer(int playerWidth, int playerHeight, int yuvImagePixelWidth, int yuvImagePixelHeight, const std::string& playerName = "");
        ~SimpleSDLPlayer();
    
    public:
        bool play(const std::string& filePath);
    
    private:
        bool initSDLInfo();
    
    private:
        // 播放器宽度
        int m_playerWindowWidth{ 0 };
        // 播放器高度
        int m_playerWindowHeight{ 0 };
        // 图像像素宽度
        int m_imagePixelWidth{ 0 };
        // 图像像素高度
        int m_imagePixelHeight{ 0 };
    
        std::string m_playerName{};
        SDL_Window *m_playerWindow{ nullptr };
        SDL_Renderer* m_sdlRenderer{ nullptr };
        SDL_Texture* m_sdlTexture{ nullptr };
    
        //IYUV: Y + U + V  (3 planes)
        //YV12: Y + V + U  (3 planes)
        Uint32 m_pixformat = SDL_PIXELFORMAT_IYUV;
    };

cpp文件如下：

#include "SimpleSDLPlayer.h"
    #include <future>
    #include <iostream>
    
    using namespace std;
    
    //Refresh Event
    #define REFRESH_EVENT  (SDL_USEREVENT + 1)
    #define BREAK_EVENT  (SDL_USEREVENT + 2)
    
    /*
     * @func   SimpleSDLPlayer::SimpleSDLPlayer 
     * @brief  构造函数
     * @param  [in]  int playerWidth  播放器宽度
     * @param  [in]  int playerHeight  播放器高度
     * @param  [in]  int yuvImagePixelWidth  yuv文件图像像素宽度
     * @param  [in]  int yuvImagePixelHeight  yuv文件图像像素高度
     * @param  [in]  const std::string & playerName  播放器名称
     * @return   
     */ 
    SimpleSDLPlayer::SimpleSDLPlayer(int playerWidth, int playerHeight, int yuvImagePixelWidth, int yuvImagePixelHeight, const std::string& playerName /*= ""*/)
    {
        m_playerWindowWidth = playerWidth;
        m_playerWindowHeight = playerHeight;
        m_imagePixelWidth = yuvImagePixelWidth;
        m_imagePixelHeight = yuvImagePixelHeight;
        m_playerName = playerName;
    
        if (!initSDLInfo())
            return;
    }
    
    SimpleSDLPlayer::~SimpleSDLPlayer()
    {
    }
    
    /*
     * @func   SimpleSDLPlayer::initSDLInfo 
     * @brief  初始化SDL
     * @return bool  
     */ 
    bool SimpleSDLPlayer::initSDLInfo()
    {
        if (SDL_Init(SDL_INIT_VIDEO))
        {
            cout << "Could not initialize SDL : " << SDL_GetError() << endl;
            return false;
        }
    
        // 播放窗口创建
        m_playerWindow = SDL_CreateWindow(m_playerName.c_str(),
            SDL_WINDOWPOS_UNDEFINED, SDL_WINDOWPOS_UNDEFINED,
            m_playerWindowWidth, m_playerWindowHeight, SDL_WINDOW_OPENGL | SDL_WINDOW_RESIZABLE);
    
        if (!m_playerWindow)
        {
            cout << "SDL: could not create window - exiting: " << SDL_GetError() << endl;
            return false;
        }
    
        // 渲染
        m_sdlRenderer = SDL_CreateRenderer(m_playerWindow, -1, 0);
        if (!m_sdlRenderer)
        {
            cout << "SDL: could not create render - exiting: " << SDL_GetError() << endl;
            return false;
        }
    
        // 纹理
        m_sdlTexture = SDL_CreateTexture(m_sdlRenderer, m_pixformat, SDL_TEXTUREACCESS_STREAMING, m_imagePixelWidth, m_imagePixelHeight);
        if (!m_sdlTexture)
        {
            cout << "SDL: could not create texture - exiting: " << SDL_GetError() << endl;
            return false;
        }
    
        return true;
    }
    
    /*
     * @func   SimpleSDLPlayer::play 
     * @brief  播放文件
     * @param  [in]  const std::string & filePath  文件路径
     * @return bool  
     */ 
    bool SimpleSDLPlayer::play(const std::string& filePath)
    {
        FILE *fp = NULL;
        fp = fopen(filePath.c_str(), "rb+");
        if (fp == NULL) 
        {
            cout << "cannot open this file" << endl;
            return false;
        }
    
        bool isOver{ false };
        // 使用std::async异步执行刷新任务 相当于开子线程执行任务
        auto fut = std::async([&]
        {
            while (!isOver)
            {
                SDL_Event event;
                event.type = REFRESH_EVENT;
                SDL_PushEvent(&event);
                SDL_Delay(40);
            }
            isOver = false;
            //Break
            SDL_Event event;
            event.type = BREAK_EVENT;
            SDL_PushEvent(&event);
    
            return 0;
        });
    
        SDL_Event event;
        SDL_Rect sdlRect;
    
        while (true) 
        {
            const int bpp = 12;
            shared_ptr<char*> pBuffer = make_shared<char*>(new char[m_imagePixelWidth * m_imagePixelHeight * bpp / 8]);
            // 等待有效事件
            SDL_WaitEvent(&event);
            if (event.type == REFRESH_EVENT) 
            {
                if (fread(*pBuffer.get(), 1, m_imagePixelWidth*m_imagePixelHeight*bpp / 8, fp) != m_imagePixelWidth*m_imagePixelHeight*bpp / 8)
                {
                    // Loop
                    fseek(fp, 0, SEEK_SET);
                    fread(*pBuffer.get(), 1, m_imagePixelWidth*m_imagePixelHeight*bpp / 8, fp);
                }
    
                SDL_UpdateTexture(m_sdlTexture, NULL, *pBuffer.get(), m_imagePixelWidth);
    
                //FIX: If window is resize
                sdlRect.x = 0;
                sdlRect.y = 0;
                sdlRect.w = m_playerWindowWidth;
                sdlRect.h = m_playerWindowHeight;
    
                SDL_RenderClear(m_sdlRenderer);
                SDL_RenderCopy(m_sdlRenderer, m_sdlTexture, NULL, &sdlRect);
                SDL_RenderPresent(m_sdlRenderer);
            }
            else if (event.type == SDL_WINDOWEVENT) 
            {
                //If Resize
                SDL_GetWindowSize(m_playerWindow, &m_playerWindowWidth, &m_playerWindowHeight);
            }
            else if (event.type == SDL_QUIT) 
            {
                isOver = true;
            }
            else if (event.type == BREAK_EVENT) 
            {
                break;
            }
        }
        SDL_Quit();
    }

--------------------

完整可运行工程，github路径：  
[https://github.com/lesliefish/FFMPEG][https_github.com_lesliefish_FFMPEG]

main函数测试代码如下：

#include "players/SimpleSDLPlayer/SimpleSDLPlayer.h"
    
    int main(int argc, char *argv[])
    {
        SimpleSDLPlayer simpleSDLPlayer(352, 288, 176, 144, "SDL2 Player");
        simpleSDLPlayer.play("suzie_qcif.yuv");
    
        return 0;
    }

[Link 1]: https://blog.csdn.net/leixiaohua1020/article/details/38868499
[https_github.com_lesliefish_FFMPEG]: https://github.com/lesliefish/FFMPEG