public static Interop.CaptureFrame TryCaptureFrame(Interop.Recv recv)
{
Interop.CaptureFrame captureFrame = new Interop.CaptureFrame();
captureFrame.frameType = recv.Capture(
out captureFrame.videoFrame,
out captureFrame.audioFrame,
out captureFrame.metadataFrame,
0);
return(captureFrame);
}
void TryReceiveFrame()
{
while (!_exitThread)
{
Interop.CaptureFrame?captureFrameOrNull;
lock (threadlock)
{
if (_recv == null)
{
continue;
}
captureFrameOrNull = RecvHelper.TryCaptureFrame(_recv);
}
if (captureFrameOrNull == null)
{
continue;
}
Interop.CaptureFrame captureFrame = captureFrameOrNull.GetValueOrDefault();
switch (captureFrame.frameType)
{
case Interop.FrameType.Video:
// Add to Queue for processing on Main thread
// We cannot free up the frame here because we need the data
// IntPtr address to be valid when processing on main thread.
// So we have to make sure to free the videoframe after processing
lock (videoFrameQueue)
{
// We only need to keep a single frame at any point
// So we can free up any previous frames first
videoFrameQueue.ForEach(vf => _recv.FreeVideoFrame(vf));
videoFrameQueue.Clear();
videoFrameQueue.Add(captureFrame.videoFrame);
}
// Send some metadata back
SendMetadataFrame(sendMetadataFrameData);
break;
case Interop.FrameType.Audio:
// Create audio buffer
// we're working in bytes, so take the size of a 32 bit sample (float) into account
int sizeInBytes = (int)captureFrame.audioFrame.NoSamples * (int)captureFrame.audioFrame.NoChannels * sizeof(float);
// Unity audio is interleaved so we need to convert from planar
Interop.AudioFrameInterleaved audioFrameInterleaved = new Interop.AudioFrameInterleaved
{
SampleRate = captureFrame.audioFrame.SampleRate,
NoChannels = captureFrame.audioFrame.NoChannels,
NoSamples = captureFrame.audioFrame.NoSamples,
TimeCode = captureFrame.audioFrame.Timecode
};
// we need a managed byte array for our buffer
byte[] audBuffer = new byte[sizeInBytes];
// pin the byte[] and get a GC handle to it
// doing it this way saves an expensive Marshal.Alloc/Marshal.Copy/Marshal.Free later
// the data will only be moved once, during the fast interleave step that is required anyway
GCHandle handle = GCHandle.Alloc(audBuffer, GCHandleType.Pinned);
// access it by an IntPtr and use it for our interleaved audio buffer
audioFrameInterleaved.Data = handle.AddrOfPinnedObject();
// Convert from float planar to float interleaved audio
_recv.UtilAudioToInterleaved(ref captureFrame.audioFrame, ref audioFrameInterleaved);
// release the pin on the byte[]
// never try to access p_data after the byte[] has been unpinned!
// that IntPtr will no longer be valid.
handle.Free();
// Add to audio buffer for processing in audio thread
lock (audioBuffer)
{
audioBuffer.AddRange(Util.ConvertByteArrayToFloat(audBuffer));
}
if (captureFrame.audioFrame.Metadata != IntPtr.Zero)
{
// Handle AudioFrame metadata
lock (audioMetadataQueue)
{
audioMetadataQueue.Add(Marshal.PtrToStringAnsi(captureFrame.audioFrame.Metadata));
}
}
// We can free up the audio frame because this already been processed
// Converted to interleaved array of floats
_recv.FreeAudioFrame(captureFrame.audioFrame);
break;
case Interop.FrameType.Metadata:
if (captureFrame.metadataFrame.Data != IntPtr.Zero)
{
// Handle MetadataFrame metadata
lock (metadataFrameQueue)
{
metadataFrameQueue.Add(Marshal.PtrToStringAnsi(captureFrame.metadataFrame.Data));
}
}
// free frames that were received
_recv.FreeMetadataFrame(captureFrame.metadataFrame);
break;
}
}
}