void ReadSampleBuffers(AVAsset asset)
{
NSError error;
assetReader = AVAssetReader.FromAsset(asset, out error);
if (error != null)
{
Console.WriteLine("Error creating Asset Reader: {0}", error.Description);
}
AVAssetTrack[] videoTracks = asset.TracksWithMediaType(AVMediaType.Video);
AVAssetTrack videoTrack = videoTracks [0];
CreateDecompressionSession(videoTrack);
var videoTrackOutput = AVAssetReaderTrackOutput.Create(videoTrack, (AVVideoSettingsUncompressed)null);
if (assetReader.CanAddOutput(videoTrackOutput))
{
assetReader.AddOutput(videoTrackOutput);
}
if (!assetReader.StartReading())
{
return;
}
while (assetReader.Status == AVAssetReaderStatus.Reading)
{
CMSampleBuffer sampleBuffer = videoTrackOutput.CopyNextSampleBuffer();
if (sampleBuffer != null)
{
VTDecodeFrameFlags flags = VTDecodeFrameFlags.EnableAsynchronousDecompression;
VTDecodeInfoFlags flagOut;
decompressionSession.DecodeFrame(sampleBuffer, flags, IntPtr.Zero, out flagOut);
sampleBuffer.Dispose();
if (presentationTimes.Count >= 5)
{
bufferSemaphore.Wait();
}
}
else if (assetReader.Status == AVAssetReaderStatus.Failed)
{
Console.WriteLine("Asset Reader failed with error: {0}", assetReader.Error.Description);
}
else if (assetReader.Status == AVAssetReaderStatus.Completed)
{
Console.WriteLine("Reached the end of the video.");
ChangeStatus();
ReadSampleBuffers(asset);
}
}
}
private void StartReadingAndWriting()
{
// Instruct the asset reader and asset writer to get ready to do work
if (!_assetReader.StartReading())
{
throw new NSErrorException(_assetReader.Error);
}
if (!_assetWriter.StartWriting())
{
throw new NSErrorException(_assetWriter.Error);
}
// Start a sample-writing session
_assetWriter.StartSessionAtSourceTime(_timeRange.Start);
// Only set audio handler(obj-c delegate) for audio-only assets, else let the video channel drive progress
AVReaderWriter audioHandler = _videoSampleBufferChannel == null ? this : null;
var audioTask = StartReadingAsync(_audioSampleBufferChannel, audioHandler);
var videoTask = StartReadingAsync(_videoSampleBufferChannel, this);
// Set up a callback for when the sample writing is finished
Task.WhenAll(audioTask, videoTask).ContinueWith(_ => {
if (_cancellationTokenSrc.Token.IsCancellationRequested)
{
_assetReader.CancelReading();
_assetWriter.CancelWriting();
throw new OperationCanceledException();
}
if (_assetReader.Status != AVAssetReaderStatus.Failed)
{
_assetWriter.FinishWriting(() => {
bool success = _assetWriter.Status == AVAssetWriterStatus.Completed;
ReadingAndWritingDidFinish(success, _assetWriter.Error);
});
}
}, _cancellationTokenSrc.Token);
}
void StartReadingAndWriting(CMTimeRange timeRange)
{
// Instruct the asset reader and asset writer to get ready to do work
if (!assetReader.StartReading())
{
throw new NSErrorException(assetReader.Error);
}
if (!assetWriter.StartWriting())
{
throw new NSErrorException(assetWriter.Error);
}
// Start a sample-writing session
assetWriter.StartSessionAtSourceTime(timeRange.Start);
Task audioTask = Start(audioSampleBufferChannel);
Task videoTask = Start(videoSampleBufferChannel);
// Set up a callback for when the sample writing is finished
Task.WhenAll(audioTask, videoTask).ContinueWith(_ => {
if (cancellationTokenSrc.Token.IsCancellationRequested)
{
assetReader.CancelReading();
assetWriter.CancelWriting();
throw new OperationCanceledException();
}
if (assetReader.Status != AVAssetReaderStatus.Failed)
{
assetWriter.FinishWriting(() => {
bool success = assetWriter.Status == AVAssetWriterStatus.Completed;
ReadingAndWritingDidFinish(success, assetWriter.Error);
});
}
}, cancellationTokenSrc.Token);
}
void ReadSampleBuffers(AVAsset asset)
{
NSError error;
assetReader = AVAssetReader.FromAsset (asset, out error);
if (error != null)
Console.WriteLine ("Error creating Asset Reader: {0}", error.Description);
AVAssetTrack[] videoTracks = asset.TracksWithMediaType (AVMediaType.Video);
AVAssetTrack videoTrack = videoTracks [0];
CreateDecompressionSession (videoTrack);
var videoTrackOutput = AVAssetReaderTrackOutput.Create (videoTrack, (AVVideoSettingsUncompressed)null);
if (assetReader.CanAddOutput (videoTrackOutput))
assetReader.AddOutput (videoTrackOutput);
if (!assetReader.StartReading ())
return;
while (assetReader.Status == AVAssetReaderStatus.Reading) {
CMSampleBuffer sampleBuffer = videoTrackOutput.CopyNextSampleBuffer ();
if (sampleBuffer != null) {
VTDecodeFrameFlags flags = VTDecodeFrameFlags.EnableAsynchronousDecompression;
VTDecodeInfoFlags flagOut;
decompressionSession.DecodeFrame (sampleBuffer, flags, IntPtr.Zero, out flagOut);
sampleBuffer.Dispose ();
if (presentationTimes.Count >= 5)
bufferSemaphore.Wait ();
} else if (assetReader.Status == AVAssetReaderStatus.Failed) {
Console.WriteLine ("Asset Reader failed with error: {0}", assetReader.Error.Description);
} else if (assetReader.Status == AVAssetReaderStatus.Completed) {
Console.WriteLine("Reached the end of the video.");
ChangeStatus ();
ReadSampleBuffers (asset);
}
}
}
