void SetupReaderAndWriter()
{
NSError error = null;
// Create asset reader and asset writer
assetReader = AVAssetReader.FromAsset(asset, out error);
if (assetReader == null)
{
throw new NSErrorException(error);
}
assetWriter = AVAssetWriter.FromUrl(outputURL, AVFileType.QuickTimeMovie, out error);
if (assetWriter == null)
{
throw new NSErrorException(error);
}
// Create asset reader outputs and asset writer inputs for the first audio track and first video track of the asset
// Grab first audio track and first video track, if the asset has them
AVAssetTrack audioTrack = asset.TracksWithMediaType(AVMediaType.Audio).FirstOrDefault();
AVAssetTrack videoTrack = asset.TracksWithMediaType(AVMediaType.Video).FirstOrDefault();
SetupAssetReaderWriterForAudio(audioTrack);
SetupAssetReaserWriterForVideo(videoTrack);
}
public bool RestartReading()
{
var result = false;
this.assetReader = AVAssetReader.FromAsset(this.videoAsset, out NSError error);
if (error == null)
{
var settings = new AVVideoSettingsUncompressed {
PixelFormatType = CVPixelFormatType.CV420YpCbCr8BiPlanarFullRange
};
this.videoAssetReaderOutput = new AVAssetReaderTrackOutput(this.videoTrack, settings);
if (this.videoAssetReaderOutput != null)
{
this.videoAssetReaderOutput.AlwaysCopiesSampleData = true;
if (this.assetReader.CanAddOutput(this.videoAssetReaderOutput))
{
this.assetReader.AddOutput(this.videoAssetReaderOutput);
result = this.assetReader.StartReading();
}
}
}
else
{
Console.WriteLine($"Failed to create AVAssetReader object: {error}");
}
return(result);
}
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);
}
}
}
