AVVideoCodecSettings CreateCodecSettingsFor(NSDictionary cleanAperture, NSDictionary aspectRatio)
{
if (cleanAperture == null && aspectRatio == null)
{
return(null);
}
var compressionSettings = new AVVideoCodecSettings {
VideoCleanAperture = cleanAperture != null ? new AVVideoCleanApertureSettings(cleanAperture) : null,
PixelAspectRatio = aspectRatio != null ? new AVVideoPixelAspectRatioSettings(aspectRatio) : null
};
return(compressionSettings);
}
void SetupAssetReaserWriterForVideo(AVAssetTrack videoTrack)
{
if (videoTrack == null)
{
return;
}
// Decompress to ARGB with the asset reader
var decompSettings = new AVVideoSettingsUncompressed {
PixelFormatType = CVPixelFormatType.CV32BGRA,
AllocateWithIOSurface = null
};
AVAssetReaderOutput output = new AVAssetReaderTrackOutput(videoTrack, decompSettings);
assetReader.AddOutput(output);
// Get the format description of the track, to fill in attributes of the video stream that we don't want to change
var formatDescription = (CMVideoFormatDescription)videoTrack.FormatDescriptions.FirstOrDefault();
// Grab track dimensions from format description
CGSize trackDimensions = formatDescription != null
? formatDescription.GetPresentationDimensions(false, false)
: videoTrack.NaturalSize;
// Grab clean aperture, pixel aspect ratio from format description
AVVideoCodecSettings compressionSettings = null;
if (formatDescription != null)
{
var cleanApertureDescr = (NSDictionary)formatDescription.GetExtension(CVImageBuffer.CleanApertureKey);
var pixelAspectRatioDescr = (NSDictionary)formatDescription.GetExtension(CVImageBuffer.PixelAspectRatioKey);
compressionSettings = CreateCodecSettingsFor(cleanApertureDescr, pixelAspectRatioDescr);
}
// Compress to H.264 with the asset writer
var videoSettings = new AVVideoSettingsCompressed {
Codec = AVVideoCodec.H264,
Width = (int)trackDimensions.Width,
Height = (int)trackDimensions.Height,
CodecSettings = compressionSettings
};
AVAssetWriterInput input = new AVAssetWriterInput(videoTrack.MediaType, videoSettings);
input.Transform = videoTrack.PreferredTransform;
assetWriter.AddInput(input);
// Create and save an instance of ReadWriteSampleBufferChannel,
// which will coordinate the work of reading and writing sample buffers
videoSampleBufferChannel = new VideoChannel(output, input, transformer);
}
AVVideoCodecSettings CreateCodecSettingsFor (NSDictionary cleanAperture, NSDictionary aspectRatio)
{
if (cleanAperture == null && aspectRatio == null)
return null;
var compressionSettings = new AVVideoCodecSettings {
VideoCleanAperture = cleanAperture != null ? new AVVideoCleanApertureSettings (cleanAperture) : null,
PixelAspectRatio = aspectRatio != null ? new AVVideoPixelAspectRatioSettings (aspectRatio) : null
};
return compressionSettings;
}
