System audio to Skype using Naudio

Question

I've been at this for a while, but made no progress. So this is my last resort! I am trying to send the system-audio (the audio I hear in my headphones) to Skype (making the persons in my call hear what I hear basically). And I thought I would do this using the Skype4comlib and naudio.

What I've done is to create a class which uses the WasapiLoopbackCapture and WaveFileWriter to write temporary data to a .wav file, and redirect audio using the SkypeSystemAudio.set_InputDevice method. But when I'm talking to somebody and I try to start recording, the person doesn't hear me anymore. I just go completely quiet and no sound is being played to the person.

I thought it would be best if I posted the whole class since it's easier to understand everything.

public class SkypeSystemAudio
{
    public NAudio.Wave.WasapiLoopbackCapture capture;
    NAudio.CoreAudioApi.MMDevice device;
    NAudio.Wave.WaveFileWriter writer;
    private Call CurrentCall = null;
    private Skype SkypeApplet;
    private const int SkypeProtocol = 9;
    private bool IsRecording = false;
    public string tempfilepath = System.IO.Directory.GetCurrentDirectory() + @"\temp.wav";
    #region Public
    public void Initialize()
    {
        device = NAudio.Wave.WasapiLoopbackCapture.GetDefaultLoopbackCaptureDevice();
        Init();
    }
    public void Initialize(NAudio.CoreAudioApi.MMDevice device)
    {
        this.device = device;
        Init();
    }
    public void StartRecording()
    {
        capture.StartRecording();
        if (CurrentCall != null)
        {

            CurrentCall.set_OutputDevice(TCallIoDeviceType.callIoDeviceTypeFile, tempfilepath);
            IsRecording = true;
        }

    }
    public void StopRecording()
    {
        capture.StopRecording();
        if (CurrentCall != null)
        {

            CurrentCall.set_OutputDevice(TCallIoDeviceType.callIoDeviceTypeFile, "");

        }
    }
    #endregion


    private void Init()
    {
        capture = new WasapiLoopbackCapture(device);
        capture.ShareMode = NAudio.CoreAudioApi.AudioClientShareMode.Shared;
        capture.DataAvailable += capture_DataAvailable;
        capture.RecordingStopped += capture_RecordingStopped;

        WaveFormat format = new WaveFormat(16000, 1); // skype wants 16 Bit samples, 16khz, mono WAV file
        //tried using the standard waveformat in the device object too. Didn't work though.

        writer = new WaveFileWriter(tempfilepath, format );

        SkypeApplet = new Skype();
        SkypeApplet.Attach(SkypeProtocol, true);
        SkypeApplet.CallStatus += SkypeApplet_CallStatus;

    }

    void SkypeApplet_CallStatus(Call pCall, TCallStatus Status)
    {
        if (Status == TCallStatus.clsRinging)
        {
            CurrentCall = pCall;
            pCall.Answer();
        }
    }

    void capture_DataAvailable(object sender, WaveInEventArgs e)
    {
        if (writer != null)
            writer.Write(e.Buffer, 0, e.BytesRecorded);
    }

    void capture_RecordingStopped(object sender, StoppedEventArgs e)
    {
        IsRecording = false;
    }


}

Does anyone know why this isn't working? I have no clues anymore what to do next.

Any help will greatly appreciated!

Answer 1

I have actually done some something similar, but not using Skype4COM.

What I did was using "Virtual Cables" just like Sebastian L suggested, this way you can control whats going in and out off skype, the downside is that you need to install the virtual cables and configure Skype to use them.

The cables will appear in audio devices as standard input/output.

I have used these cables VAC and VB cable

Hope it helps.