AVMutableVideoComposition output video shrinked - ios

Question

I'm a newbie to Swift. I'm trying to add a watermark with reference to code from SO. My original video resolution is 1280 X 720, but the output video is a shrunk version.
Here are the before and after pictures
Here is my function to create a watermark.
private func watermark(video videoAsset:AVAsset, watermarkText text : String!, image : CGImage!, saveToLibrary flag : Bool, completion : ((_ status : AVAssetExportSessionStatus?, _ session: AVAssetExportSession?, _ outputURL : URL?) -> ())?) {
DispatchQueue.global(qos: DispatchQoS.QoSClass.default).async {
let mixComposition = AVMutableComposition()
let compositionVideoTrack = mixComposition.addMutableTrack(withMediaType: AVMediaTypeVideo, preferredTrackID: Int32(kCMPersistentTrackID_Invalid))
let clipVideoTrack = videoAsset.tracks(withMediaType: AVMediaTypeVideo)[0]
do {
try compositionVideoTrack.insertTimeRange(CMTimeRangeMake(kCMTimeZero, videoAsset.duration), of: clipVideoTrack, at: kCMTimeZero)
}
catch {
print(error.localizedDescription)
}
let videoSize = clipVideoTrack.naturalSize
print("Video size", videoSize.height) //720
print("Video size", videoSize.width) //1280
let parentLayer = CALayer()
let videoLayer = CALayer()
parentLayer.frame = CGRect(x: 0.0,
y: 0.0,
width: videoSize.width,
height: videoSize.height)
videoLayer.frame = CGRect(x: 0.0,
y: 0.0,
width: videoSize.width,
height: videoSize.height)
parentLayer.addSublayer(videoLayer)
if text != nil {
let titleLayer = CATextLayer()
titleLayer.backgroundColor = UIColor.red.cgColor
titleLayer.string = text
titleLayer.font = "Helvetica" as CFTypeRef
titleLayer.fontSize = 15
titleLayer.alignmentMode = kCAAlignmentCenter
titleLayer.bounds = CGRect(x: 0, y: 0, width: videoSize.width, height: videoSize.height)
parentLayer.addSublayer(titleLayer)
} else if image != nil {
let imageLayer = CALayer()
imageLayer.contents = image
let width: CGFloat = (self.imageView.image?.size.width)!
let height: CGFloat = (self.imageView.image?.size.height)!
print("Video size", height) //720
print("Video size", width) //1280
imageLayer.frame = CGRect(x: 0.0, y: 0.0, width: width, height: height)
imageLayer.opacity = 0.65
parentLayer.addSublayer(imageLayer)
}
let videoComp = AVMutableVideoComposition()
videoComp.renderSize = videoSize
videoComp.frameDuration = CMTimeMake(1, Int32(clipVideoTrack.nominalFrameRate))
videoComp.animationTool = AVVideoCompositionCoreAnimationTool(postProcessingAsVideoLayer: videoLayer, in: parentLayer)
let instruction = AVMutableVideoCompositionInstruction()
instruction.timeRange = CMTimeRangeMake(kCMTimeZero, mixComposition.duration)
_ = mixComposition.tracks(withMediaType: AVMediaTypeVideo)[0] as AVAssetTrack
let layerInstruction = self.videoCompositionInstructionForTrack(track: compositionVideoTrack, asset: videoAsset)
instruction.layerInstructions = [layerInstruction]
videoComp.instructions = [instruction]
let documentDirectory = NSSearchPathForDirectoriesInDomains(.documentDirectory, .userDomainMask, true)[0]
let dateFormatter = DateFormatter()
dateFormatter.dateStyle = .long
dateFormatter.timeStyle = .short
let date = dateFormatter.string(from: Date())
let url = URL(fileURLWithPath: documentDirectory).appendingPathComponent("watermarkVideo-\(date).mov")
let exporter = AVAssetExportSession(asset: mixComposition, presetName: AVAssetExportPresetHighestQuality)
exporter?.outputURL = url
exporter?.outputFileType = AVFileTypeQuickTimeMovie
exporter?.shouldOptimizeForNetworkUse = true
exporter?.videoComposition = videoComp
exporter?.exportAsynchronously() {
DispatchQueue.main.async {
if exporter?.status == AVAssetExportSessionStatus.completed {
let outputURL = exporter?.outputURL
if flag {
if UIVideoAtPathIsCompatibleWithSavedPhotosAlbum(outputURL!.path) {
PHPhotoLibrary.shared().performChanges({
PHAssetChangeRequest.creationRequestForAssetFromVideo(atFileURL: outputURL!)
}) { saved, error in
if saved {
completion!(AVAssetExportSessionStatus.completed, exporter, outputURL)
}
}
}
} else {
completion!(AVAssetExportSessionStatus.completed, exporter, outputURL)
}
} else {
// Error
completion!(exporter?.status, exporter, nil)
}
}
}
}
}
While the size of the watermark image is correct, the video is shrunk.

Answer 1

can you try this function
private func watermark(video videoAsset: AVAsset, watermarkText text : String!, image : CGImage!, saveToLibrary flag : Bool, completion : ((_ status : AVAssetExportSessionStatus ?, _ session: AVAssetExportSession ?, _ outputURL : URL ?) -> ())?) {
DispatchQueue.global(qos: DispatchQoS.QoSClass.default).async {
let mixComposition = AVMutableComposition()
let compositionVideoTrack = mixComposition.addMutableTrack(withMediaType: AVMediaTypeVideo, preferredTrackID: Int32(kCMPersistentTrackID_Invalid))
let clipVideoTrack = videoAsset.tracks(withMediaType: AVMediaTypeVideo)[0] as AVAssetTrack
do {
try compositionVideoTrack.insertTimeRange(CMTimeRangeMake(kCMTimeZero, videoAsset.duration), of: clipVideoTrack, at: kCMTimeZero)
}
catch {
print(error.localizedDescription)
}
let videoSize = clipVideoTrack.naturalSize
let parentLayer = CALayer()
let videoLayer = CALayer()
parentLayer.frame = CGRect(x: 0.0,
y: 0.0,
width: videoSize.width,
height: videoSize.height)
videoLayer.frame = CGRect(x: 0.0,
y: 0.0,
width: videoSize.width,
height: videoSize.height)
parentLayer.addSublayer(videoLayer)
// if text != nil {
// let titleLayer = CATextLayer()
// titleLayer.backgroundColor = UIColor.red.cgColor
// titleLayer.string = text
// titleLayer.font = "Helvetica" as CFTypeRef
// titleLayer.fontSize = 15
// titleLayer.alignmentMode = kCAAlignmentCenter
// titleLayer.frame = CGRect(x: 0, y: 0, width: videoSize.width, height: videoSize.height)
// parentLayer.addSublayer(titleLayer)
// } else
if image != nil {
let imageLayer = CALayer()
imageLayer.contents = image
let width: CGFloat = (self.imageView.image ?.size.width)!
let height: CGFloat = (self.imageView.image ?.size.height)!
//
print("Video size", height)
print("Video size", width)
imageLayer.frame = CGRect(x: 0, y: 0, width: width, height: height)
// imageLayer.frame = CGRect(x: 0, y: 0, width: videoSize.width, height: videoSize.height)
imageLayer.opacity = 1
parentLayer.addSublayer(imageLayer)
}
let videoComp = AVMutableVideoComposition()
videoComp.renderSize = videoSize
videoComp.frameDuration = CMTimeMake(1, Int32(clipVideoTrack.nominalFrameRate))
videoComp.animationTool = AVVideoCompositionCoreAnimationTool(postProcessingAsVideoLayer: videoLayer, in: parentLayer)
let instruction = AVMutableVideoCompositionInstruction()
instruction.timeRange = CMTimeRangeMake(kCMTimeZero, mixComposition.duration)
let videotrack = mixComposition.tracks(withMediaType: AVMediaTypeVideo)[0] as AVAssetTrack
let layerInstruction = AVMutableVideoCompositionLayerInstruction(assetTrack: videotrack)
// let layerInstruction = self.videoCompositionInstructionForTrack(track: compositionVideoTrack, asset: videoAsset)
instruction.layerInstructions = [layerInstruction]
videoComp.instructions = [instruction]
let documentDirectory = NSSearchPathForDirectoriesInDomains(.documentDirectory, .userDomainMask, true)[0]
let dateFormatter = DateFormatter()
dateFormatter.dateStyle = .long
dateFormatter.timeStyle = .short
let date = dateFormatter.string(from: Date())
let url = URL(fileURLWithPath: documentDirectory).appendingPathComponent("watermarkVideo-\(date).mp4")
guard let exporter = AVAssetExportSession(asset: mixComposition, presetName: AVAssetExportPresetHighestQuality) else { return}
exporter.videoComposition = videoComp
exporter.outputFileType = AVFileTypeMPEG4
exporter.outputURL = url
exporter.exportAsynchronously() {
DispatchQueue.main.async {
if exporter.status == AVAssetExportSessionStatus.completed {
let outputURL = exporter.outputURL
if flag {
// Save to library
// let library = ALAssetsLibrary()
if UIVideoAtPathIsCompatibleWithSavedPhotosAlbum(outputURL!.path) {
PHPhotoLibrary.shared().performChanges({
PHAssetChangeRequest.creationRequestForAssetFromVideo(atFileURL: outputURL!)
}) {
saved, error in
if saved {
completion!(AVAssetExportSessionStatus.completed, exporter, outputURL)
}
}
}
// if library.videoAtPathIs(compatibleWithSavedPhotosAlbum: outputURL) {
// library.writeVideoAtPathToSavedPhotosAlbum(outputURL,
// completionBlock: { (assetURL:NSURL!, error:NSError!) -> Void in
//
// completion!(AVAssetExportSessionStatus.Completed, exporter, outputURL)
// })
// }
} else {
completion!(AVAssetExportSessionStatus.completed, exporter, outputURL)
}
} else {
// Error
completion!(exporter.status, exporter, nil)
}
}
}
}
}

Answer 2

The code above for creating the watermarked video seems not to be the reason for the smaller output resolution.
Problem
The resolution depends on what kind of AVAsset is put into the watermark method.
Example:
Frequently an UIImagePickerController is used. There is the delegate method
func imagePickerController(_ picker: UIImagePickerController, didFinishPickingMediaWithInfo info: [String : Any])
There one often can see something like this:
let url = info[UIImagePickerControllerMediaURL] as? URL
let videoAsset = AVAsset(url: url!)
self.watermark(video: videoAsset, watermarkText: nil, image: self.imageView.image?.cgImage ...
But with the lines above a downsized input image is used, e.g. instead of having a video with 1920x1080 one has a reduced video size of 1280x720.
Solution
A method for determining the AVAsset from the PHAsset could look like this:
private func videoAsset(for asset: PHAsset, completion: #escaping (AVAsset?) -> Void) {
let requestOptions = PHVideoRequestOptions()
requestOptions.version = .original
PHImageManager.default().requestAVAsset(forVideo: asset, options: requestOptions, resultHandler: {
(avAsset, avAudioMix, info) in
completion(avAsset)
})
}
And where to get the PHAsset from? It can also be determined in the didFinishPickingMediaWithInfo method by using UIImagePickerControllerPHAsset:
let asset = info[UIImagePickerControllerPHAsset] as? PHAsset
Quick Test
For a quick test one could use:
func imagePickerController(_ picker: UIImagePickerController, didFinishPickingMediaWithInfo info: [String : Any]) {
if let asset = info[UIImagePickerControllerPHAsset] as? PHAsset {
picker.dismiss(animated: true, completion: { [weak self] in
self?.videoAsset(for: asset, completion: { (avAsset) in
if let videoAsset = avAsset {
DispatchQueue.main.async {
self?.watermark(video: videoAsset, watermarkText: nil, image: self?.imageView.image?.cgImage, saveToLibrary: true) { (exportStat: AVAssetExportSessionStatus? , session: AVAssetExportSession?, url: URL?) in
print("url: \(String(describing: url?.debugDescription))")
}
}
}
})
})
}
}
The result is a video in the original resolution with a watermark on the lower left, see screenshot of resulting video: