FFmpeg对UE4相机画面实时推流

星辰hxy

于 2025-03-09 15:38:22 发布

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文章标签： ffmpeg ue4 c++

本文链接：https://blog.youkuaiyun.com/qq_45942988/article/details/146102631

版权

大家好，这篇博客的主要内容是把自己在校做的项目的方法和大家分享，主要内容是使用C++将UE4的虚拟相机画面通过ffmpeg进行推流，主要涉及三部分内容：首先是UE4的虚拟相机画面实时获取，接着准备rtsp服务器，最后使用ffmpeg推流。

该功能基于Unreal Engine4.27平台，下面介绍如何实现（由于具体的实现细节比较多，全部都写上比较麻烦，所以这里只写个大概实现流程，如果有需要的话可以给我留言）：

1.准备渲染目标Render Target

参考：

版权声明：本文为优快云博主「Shiyoku」的原创文章，遵循CC 4.0 BY-SA版权协议，转载请附上原文出处链接及本声明。
原文链接：https://blog.youkuaiyun.com/Shiyoku/article/details/121699097

不过这里我们只需要创建出渲染目标Render Target即可。

2.创建UE4 C++项目

2.1 在UE4中创建好C++类，选择继承Actor，将cpp代码命名为CameraReader（建议和我一样，否则后面需要改代码里的一些名称）

2.2 代码主要部分如下（想要全部代码的可以找我）

void ACameraReader::start() {
    if (!Camera_Texture2D || !Camera_RenderTarget2)
        UE_LOG(LogTemp, Error, TEXT("Error CameraTarget"));
    //FRenderTarget类提供的从渲染目标读取像素数据的方法
    FRenderTarget* RenderTarget = Camera_RenderTarget2->GameThread_GetRenderTargetResource(); 
    //将像素数据传给ColorData数组
    RenderTarget->ReadPixels(ColorData); 
    //获取颜色数据
    frame2 = cv::Mat(cvSize, CV_8UC4, ColorData.GetData());

    //展示opencv窗口；；；用于展示获取到的虚拟相机画面
    if (!frame2.empty())
        cv::imshow("Display2", frame2);

    if (cv::waitKey(1) == 27) // 按下ESC键退出
        EXIT();

    if (frame2.empty()) {
        UE_LOG(LogTemp, Error, TEXT("Failed to read frame from camera"));
        return;
    }

    //下面使用ffmpeg进行实时推流虚拟相机画面
    const int stride[] = { static_cast<int>(frame2.step[0]) };
    sws_scale(sws_ctx2, &frame2.data, stride, 0, VideoSize.Y, dstFrame2->data, dstFrame2->linesize);

    dstFrame2->pts += av_rescale_q(1, mDstVideoCodecCtx2->time_base, mDstVideoStream2->time_base);
    ret2 = avcodec_send_frame(mDstVideoCodecCtx2, dstFrame2);
    if (ret2 < 0) {
        UE_LOG(LogTemp, Error, TEXT("Error sending frame to encoder"));
        return;
    }

    AVPacket pkt;
    av_init_packet(&pkt);
    ret2 = avcodec_receive_packet(mDstVideoCodecCtx2, &pkt);
    if (ret2 < 0) {
        UE_LOG(LogTemp, Log, TEXT("Error encoding a frame"));
        av_packet_unref(&pkt);
        return;
    }

    pkt.stream_index = mDstVideoIndex2;
    
    ret2 = av_interleaved_write_frame(mDstFmtCtx2, &pkt);
    if (ret2 < 0) {
        UE_LOG(LogTemp, Error, TEXT("Error while writing frame to output"));
        return;
    } 
    av_packet_unref(&pkt);
}

3.rtsp服务器下载及环境配置

推流需要使用rtsp服务器，这里使用zlm Media，以及opencv库和ffmpeg库：

这里下载：
链接: https://pan.baidu.com/s/1u8Vo2r7IcHhv8aZe9JJxAw?pwd=etat 提取码: etat

3.1.zlm Media使用

解压zlm-master文件夹后，进入V2023.3.25.windows文件夹，双击打开”start.bat”，这个是推流服务器。

在V2023.3.25.windows文件夹中，找到config.ini，双击打开，找到[rtsp]部分，需要记住port端口号，用于后面的rtsp地址设置

3.2.opencv和ffmpeg库配置

3.2.1 环境变量

右击此电脑打开环境变量，在Path中，加入路径：

..\opencv\build\x64\vc15\bin

..\ffmpeg-win64-shared-4.4\ffmpeg-win64-shared-4.4\bin

如下：

3.2.2 UE4环境设置

在UE4的项目文件夹中，将下面的ThirdParty文件夹解压到项目文件夹：
链接: https://pan.baidu.com/s/17IsBdVuQyedF4iGzGfGFfg?pwd=6iab 提取码: 6iab

之后还需要设置UE4的C++项目build.cs文件，在public class MyProject01 : ModuleRules{}里添加如下代码（这里的MyProject01是我的项目名称）：

public class MyProject01 : ModuleRules
{
    string OPENCV_VERSION = "455";

    private string ThirdPartyPath
    {
        get
        {
            return Path.GetFullPath(Path.Combine(ModuleDirectory, "../../ThirdParty/"));
        }
    }

    public bool LoadOpenCV(ReadOnlyTargetRules Target)
    {
        // only set up for Win64
        bool isLibrarySupported = false;

        // Create OpenCV Path 
        string OpenCVPath = Path.Combine(ThirdPartyPath, "OpenCV");

        // Get Library Path 
        string LibPath = "";
        bool isdebug = Target.Configuration == UnrealTargetConfiguration.Debug;
        if (Target.Platform == UnrealTargetPlatform.Win64)
        {
            LibPath = Path.Combine(OpenCVPath, "Libraries", "Win64");
            isLibrarySupported = true;
        }
        else
        {
            string Err = string.Format("{0} dedicated server is made to depend on {1}. We want to avoid this, please correct module dependencies.", Target.Platform.ToString(), this.ToString());
            System.Console.WriteLine(Err);
        }

        if (isLibrarySupported)
        {
            //Add Include path 
            PublicIncludePaths.AddRange(new string[] { Path.Combine(OpenCVPath, "Includes") });
            //Add Static Libraries
            PublicAdditionalLibraries.Add(Path.Combine(LibPath, "opencv_world" + OPENCV_VERSION + ".lib"));
            //Add Dynamic Libraries
            PublicDelayLoadDLLs.Add("opencv_world" + OPENCV_VERSION + ".dll");
            PublicDelayLoadDLLs.Add("opencv_videoio_ffmpeg" + OPENCV_VERSION + "_64.dll");
        }
        PublicDefinitions.Add(string.Format("WITH_OPENCV_BINDING={0}", isLibrarySupported ? 1 : 0));
        return isLibrarySupported;
    }

    public bool LoadFFmpeg(ReadOnlyTargetRules Target)
    {
        bool isLibrarySupported = false;
        string FFmpegPath = Path.Combine(ThirdPartyPath, "FFmpeg");
        string LibPath = "";

        if (Target.Platform == UnrealTargetPlatform.Win64)
        {
            LibPath = Path.Combine(FFmpegPath, "Libraries", "Win64");
            isLibrarySupported = true;
        }
        else
        {
            string Err = string.Format("{0} dedicated server is made to depend on {1}. We want to avoid this, please correct module dependencies.", Target.Platform.ToString(), this.ToString());
            System.Console.WriteLine(Err);
        }

        if (isLibrarySupported)
        {
            PublicIncludePaths.Add(Path.Combine(FFmpegPath, "includes"));
            PublicAdditionalLibraries.Add(Path.Combine(LibPath, "avcodec.lib"));
            PublicAdditionalLibraries.Add(Path.Combine(LibPath, "avdevice.lib"));
            PublicAdditionalLibraries.Add(Path.Combine(LibPath, "avfilter.lib"));
            PublicAdditionalLibraries.Add(Path.Combine(LibPath, "avformat.lib"));
            PublicAdditionalLibraries.Add(Path.Combine(LibPath, "avutil.lib"));
            PublicAdditionalLibraries.Add(Path.Combine(LibPath, "postproc.lib"));
            PublicAdditionalLibraries.Add(Path.Combine(LibPath, "swresample.lib"));
            PublicAdditionalLibraries.Add(Path.Combine(LibPath, "swscale.lib"));


            PublicDelayLoadDLLs.Add("avcodec-58.dll");
            PublicDelayLoadDLLs.Add("avdevice-58.dll");
            PublicDelayLoadDLLs.Add("avfilter-7.dll");
            PublicDelayLoadDLLs.Add("avformat-58.dll");
            PublicDelayLoadDLLs.Add("avutil-56.dll");
            PublicDelayLoadDLLs.Add("postproc-55.dll");
            PublicDelayLoadDLLs.Add("swresample-3.dll");
            PublicDelayLoadDLLs.Add("swscale-5.dll");
        }
        PublicDefinitions.Add(string.Format("WITH_FFMPEG_BINDING={0}", isLibrarySupported ? 1 : 0));
        return isLibrarySupported;
    }




    public MyProject01(ReadOnlyTargetRules Target) : base(Target)
    {
        bEnableUndefinedIdentifierWarnings = false; //避免Windows中的宏与UE4冲突

        PCHUsage = PCHUsageMode.UseExplicitOrSharedPCHs;

        PublicDependencyModuleNames.AddRange(new string[] { "Core", "CoreUObject", "Engine", "InputCore" });

        PrivateDependencyModuleNames.AddRange(new string[] { });

        // Uncomment if you are using Slate UI
        // PrivateDependencyModuleNames.AddRange(new string[] { "Slate", "SlateCore" });

        // Uncomment if you are using online features
        // PrivateDependencyModuleNames.Add("OnlineSubsystem");

        // To include OnlineSubsystemSteam, add it to the plugins section in your uproject file with the Enabled attribute set to true
        LoadOpenCV(Target);
        LoadFFmpeg(Target);
    }
}