Mux Audio and Video Into MP4

This topic describes how to use the Transcoder class to mux AAC audio and H.264 video into an MP4 file.

mux_mp4_avc_aac_file Sample

The code snippets in this article are from the mux_mp4_avc_aac_file sample app. The complete source code of the mux_mp4_avc_aac_file app is available in the following BitBucket repository:

Complete .NET code

static bool MP4Mux(Options opt)
{
    bool audioStreamDetected = false;
    bool videoStreamDetected = false;

    using (var transcoder = new Transcoder())
    {
        // Transcoder demo mode must be enabled,
        // in order to use the production release for testing (without a valid license).
        transcoder.AllowDemoMode = true;

        // configure inputs
        foreach (string inputFile in opt.InputFiles)
        {
            using (MediaInfo info = new MediaInfo())
            {
                info.InputFile = inputFile;

                if (!info.Load())
                {
                    PrintError("mediaInfo.Load", info.Error);
                    return false;
                }

                MediaSocket inputSocket = MediaSocket.FromMediaInfo(info);

                for (int i = 0; i < inputSocket.Pins.Count; i++)
                {
                    MediaPin pin = inputSocket.Pins[i];

                    if(pin.StreamInfo.StreamType == StreamType.H264)
                    {
                        if(videoStreamDetected)
                        {
                            pin.Connection = PinConnection.Disabled;
                        }
                        else
                        {
                            videoStreamDetected = true;
                            Console.WriteLine("Muxing video input: {0}", inputFile);
                        }
                    }
                    else if(pin.StreamInfo.StreamType == StreamType.Aac)
                    {
                        if(audioStreamDetected)
                        {
                            pin.Connection = PinConnection.Disabled;
                        }
                        else
                        {
                            audioStreamDetected = true;
                            Console.WriteLine("Muxing audio input: {0}", inputFile);
                        }
                    }
                    else
                    {
                        pin.Connection = PinConnection.Disabled;
                    }
                }

                transcoder.Inputs.Add(inputSocket);
            }
        }

        // Configure output
        {
            MediaSocket socket = new MediaSocket();
            socket.File = opt.OutputFile;
            socket.StreamType = StreamType.Mp4;

            if(videoStreamDetected)
            {
                VideoStreamInfo streamInfo = new VideoStreamInfo();
                streamInfo.StreamType = StreamType.H264;
                streamInfo.StreamSubType = StreamSubType.Avc1;

                MediaPin pin = new MediaPin();
                pin.StreamInfo = streamInfo;
                socket.Pins.Add(pin);
            }

            if (audioStreamDetected)
            {
                AudioStreamInfo streamInfo = new AudioStreamInfo();
                streamInfo.StreamType = StreamType.Aac;
                streamInfo.StreamSubType = StreamSubType.AacMp4;

                MediaPin pin = new MediaPin();
                pin.StreamInfo = streamInfo;
                socket.Pins.Add(pin);
            }

            if(opt.FastStart)
            {
                socket.Params.Add(Param.Muxer.MP4.FastStart, 1);
            }

            transcoder.Outputs.Add(socket);
        }

        bool res = transcoder.Open();
        PrintError("Open Transcoder", transcoder.Error);
        if (!res)
            return false;

        res = transcoder.Run();
        PrintError("Run Transcoder", transcoder.Error);
        if (!res)
            return false;

        transcoder.Close();
    }

    return true;
}


Last updated on November 28th, 2017 02:38:41 PM