Qt+FFmpeg+SDL 实现多路多格式原始视频播放工具：从像素处理到实时渲染

一、概述

　　　　本文基于 Qt、FFmpeg AVFrame 和 SDL 库构建的高性能多路多格式原始视频播放工具。系统支持同时播放 RGBA、ARGB、RGB24、YUV420P 等多种像素格式的原始视频流，核心技术包括：
　　多格式播放：直接播放的是原始视频文件，例如：RGBA、ARGB、YUV420P、RGB24
　　像素格式转换：利用 libswscale 实现 YUV420P 到 RGB 系列格式的高效转换，支持以上4中视频文件格式的互转。
　　多路同步渲染：基于 SDL2 的渲染器，为每路视频创建独立纹理，通过 Qt 界面实现统一管理。

　　界面如下：

　　

 　　制作步骤：

• 首先是界面的编写（如上图）。可显示两路视频，原始视频的格式可以是YUV420P、RGBA、ARGB、RGB24中的任意两种
• 编写多路多格式视频播放控制类进行统一管理。此处使用C++11的thread线程用于渲染，防止占用主线程导致程序卡死

二、代码示例

1. 界面类：SDLRenderAVFrameWindow【源码】
   • 选择视频1然后开始播放

     void SDLRenderAVFrameWindow::selectVideo1Func()
     {
         QString filter = "RGB 文件 (*.*);;所有文件 (*.*)";
         // 打开文件选择对话框，选择单个文件
         QString filePath = QFileDialog::getOpenFileName(this, "选择 RGB 文件", "", filter);
         if (filePath.isEmpty()) {
             return;
         }
         if (playController1)
         {
             delete playController1;
             playController1 = nullptr;
         }
         playController1 = MultipleVideosPlayController::Create();
         playController1->Close();
         playController1->mWidth = ui.video1Width->text().toInt();
         playController1->mHeight = ui.video1Height->text().toInt();
         playController1->mPixFormat = m_fmt1;
         playController1->win_id = (void*)ui.labelVideo1->winId();
         playController1->fps = ui.editFps1->text().toInt();
         playController1->mFilePath = filePath;
         playController1->Init();
         playController1->callback = [this](int fps) {
             qDebug() << "执行了回调函数1";
             ui.labelFps1->setText(QString::number(fps));
             };
         playController1->Start();
         //playController1->Draw();
     }

      

   • 选择视频2然后开始播放

     void SDLRenderAVFrameWindow::selectVideo2Func()
     {
         QString filter = "RGB 文件 (*.*);;所有文件 (*.*)";
         // 打开文件选择对话框，选择单个文件
         QString filePath = QFileDialog::getOpenFileName(this, "选择 RGB 文件", "", filter);
         if (filePath.isEmpty()) {
             return;
         }
         if (playController2)
         {
             delete playController2;
             playController2 = nullptr;
         }
         playController2 = MultipleVideosPlayController::Create();
         playController2->Close();
         playController2->mWidth = ui.video2Width->text().toInt();
         playController2->mHeight = ui.video2Height->text().toInt();
         playController2->mPixFormat = m_fmt2;
         playController2->win_id = (void*)ui.labelVideo2->winId();
         playController2->mFilePath = filePath;
         playController2->fps = ui.editFps2->text().toInt();
         playController2->Init();
         playController2->callback = [this](int fps) {
             qDebug() << "执行了回调函数2";
             ui.labelFps2->setText(QString::number(fps));
             };
         playController2->Start();
         //playController2->Draw();
     }

      

2. 控制器类：SDLRenderAVFrameWindow【源码】
   • 初始化参数及SDL2渲染器

     QString MultipleVideosPlayController::Init()
     {
         binaryFileReader = BinaryFileReader::Create();
         iVideoRenderView = IVideoRenderView::Create(IVideoRenderView::SDL);
         if (mWidth <= 0 || mHeight <= 0 || win_id == NULL)
         {
             qDebug() << "请设要播放文件的宽高";
             QString errorMsg = "请设要播放文件的宽高";
             return errorMsg;
         }
     
         binaryFileReader->filename = mFilePath.toStdString();
         binaryFileReader->width = mWidth;
         binaryFileReader->height = mHeight;
         binaryFileReader->Init();
     
         IVideoRenderView::PixFormat mFormat = IVideoRenderView::PixFormat::RGBA;
         switch (mPixFormat) {
         case 0:
             mFormat = IVideoRenderView::PixFormat::RGBA;
             data = new  char[mWidth * mHeight * 4];
             linesize = mWidth * mHeight * 4;
             break;
         case 1:
             mFormat = IVideoRenderView::PixFormat::ARGB;
             data = new  char[mWidth * mHeight * 4];
             linesize = mWidth * mHeight * 4;
             break;
         case 2:
             mFormat = IVideoRenderView::PixFormat::RGB24;
             data = new  char[mWidth * mHeight * 3];
             linesize = mWidth * mHeight * 3;
             break;
         case 3:
             mFormat = IVideoRenderView::PixFormat::YUV420P;
             data = new  char[mWidth * mHeight * 1.5];
             linesize = mWidth * mHeight * 1.5;
             break;
         }
         iVideoRenderView->Init(mWidth, mHeight, mFormat, win_id);
         return NULL;
     }

      

   • 开启线程，并指定Draw方法运行在子线程中

     void MultipleVideosPlayController::Start()
     {
         // 创建并启动后台线程
         renderThread = std::make_unique<std::thread>(&MultipleVideosPlayController::Draw, this);
     }

      

   • 把Frame绘制到SDL中

     /// <summary>
     /// 线程函数，执行了线程
     /// </summary>
     void MultipleVideosPlayController::Draw()
     {
         for (;;)
         {
             if (!isRunning)break;
             bool ret = binaryFileReader->Read(data, linesize);
             AVFrame* frame = GetFrame(data);
             if (!ret) {
                 break;
             }
             iVideoRenderView->DrawFrame(frame);
             av_frame_free(&frame);//释放掉AVFrame
             if (fps <= 0)
             {
                 fps = 25;
             }
             int secondMs = (int)(1000 / fps);
             //std::this_thread::sleep_for(33ms);
             std::this_thread::sleep_for(std::chrono::milliseconds(secondMs));
             int renderFps = iVideoRenderView->RenderFps();
             callback(renderFps);
         }
         qDebug() << "已释放了data内存";
     }
     

      

   • SDL2的DrawFrame具体如下

     bool SDLVideoRenderView::DrawFrame(AVFrame* frame)
     {
         if (!frame || !frame->data[0])return false;
         unique_lock<mutex> sdl_lock(m_mutex);
         m_count++;
         if (m_beg_ms <= 0)
         {
             m_beg_ms = clock();
         }
         //计算显示帧率
         else if ((clock() - m_beg_ms) / (CLOCKS_PER_SEC / 1000) >= 1000) //一秒计算一次fps
         {
             m_render_fps = m_count;
             m_count = 0;
             m_beg_ms = clock();
         }
     
         switch (frame->format)
         {
         case AV_PIX_FMT_YUV420P:
             return renderUtil->DrawFrame(frame->data[0], frame->data[1], frame->data[2], frame->linesize[0], frame->linesize[1], frame->linesize[2]);
         case AV_PIX_FMT_BGRA:
         case AV_PIX_FMT_ARGB:
         case AV_PIX_FMT_RGBA:
         case AV_PIX_FMT_RGB24:
             return renderUtil->DrawFrame(frame->data[0], frame->linesize[0]);
         }
         return true;
     }