/// <summary>
/// Create an audio track from a local audio capture device (microphone).
/// This does not add the track to any peer connection. Instead, the track must be added manually to
/// an audio transceiver to be attached to a peer connection and transmitted to a remote peer.
/// </summary>
/// <param name="settings">Settings to initialize the local audio track.</param>
/// <returns>Asynchronous task completed once the device is capturing and the track is created.</returns>
/// <remarks>
/// On UWP this requires the "microphone" capability.
/// See <see href="https://docs.microsoft.com/en-us/windows/uwp/packaging/app-capability-declarations"/>
/// for more details.
/// </remarks>
public static Task <LocalAudioTrack> CreateFromDeviceAsync(LocalAudioTrackSettings settings = null)
{
return(Task.Run(() =>
{
// On UWP this cannot be called from the main UI thread, so always call it from
// a background worker thread.
string trackName = settings?.trackName;
if (string.IsNullOrEmpty(trackName))
{
trackName = Guid.NewGuid().ToString();
}
// Create interop wrappers
var track = new LocalAudioTrack(trackName);
// Parse settings
var config = new PeerConnectionInterop.LocalAudioTrackInteropInitConfig(track, settings);
// Create native implementation objects
uint res = LocalAudioTrackInterop.LocalAudioTrack_CreateFromDevice(config, trackName,
out LocalAudioTrackHandle trackHandle);
Utils.ThrowOnErrorCode(res);
track.SetHandle(trackHandle);
return track;
}));
}
/// <inheritdoc/>
public void Dispose()
{
if (_nativeHandle.IsClosed)
{
return;
}
// Remove the track from the peer connection, if any
if (Transceiver != null)
{
Debug.Assert(PeerConnection != null);
Debug.Assert(Transceiver.LocalTrack == this);
Transceiver.LocalAudioTrack = null;
}
Debug.Assert(PeerConnection == null);
Debug.Assert(Transceiver == null);
// Unregister interop callbacks
if (_selfHandle != IntPtr.Zero)
{
LocalAudioTrackInterop.LocalAudioTrack_RegisterFrameCallback(_nativeHandle, null, IntPtr.Zero);
Utils.ReleaseWrapperRef(_selfHandle);
_selfHandle = IntPtr.Zero;
_interopCallbackArgs = null;
}
// Destroy the native object. This may be delayed if a P/Invoke callback is underway,
// but will be handled at some point anyway, even if the managed instance is gone.
_nativeHandle.Dispose();
}
private void RegisterInteropCallbacks()
{
_interopCallbackArgs = new LocalAudioTrackInterop.InteropCallbackArgs()
{
Track = this,
FrameCallback = LocalAudioTrackInterop.FrameCallback,
};
_selfHandle = Utils.MakeWrapperRef(this);
LocalAudioTrackInterop.LocalAudioTrack_RegisterFrameCallback(
_nativeHandle, _interopCallbackArgs.FrameCallback, _selfHandle);
}