First Video Is Coming after merge different videos - ios

Question

I am creating a video collage app in which I am merging multiple videos in different frames and make a single video. But all frames are showing first video. Another videos are not showing after merge. Please give me suggestion as soon as possible. My code is below.
func newoverlay() {
// 1 - Create AVMutableComposition object. This object will hold your AVMutableCompositionTrack instances.
let mixComposition = AVMutableComposition()
var arrayOfComposition = Array<AVMutableCompositionTrack>()
var trackInstruction = Array<AVVideoCompositionLayerInstruction>()
var videolayer = Array<CALayer>()
var i:Int = 0
let mainInstruction = AVMutableVideoCompositionInstruction()
var assetDuration:CMTime = CMTime.zero
var box = Array<CALayer>()
var arrOfIns = Array<AVMutableVideoCompositionInstruction>()
var atTimeM : CMTime = CMTimeMake(value: 0, timescale: 0)
var lastAsset: AVURLAsset!
// 2 - Create two video tracks
for videoAssetss in firstAsset {
guard var firstTrack = mixComposition.addMutableTrack(withMediaType: .video,
preferredTrackID: Int32(kCMPersistentTrackID_Invalid)) else { return }
do {
try firstTrack.insertTimeRange(CMTimeRangeMake(start: CMTime.zero, duration: (videoAssetss as? AVURLAsset)!.duration),
of: (videoAssetss as? AVURLAsset)!.tracks(withMediaType: .video)[0],
at: CMTime.zero)
var firstInstruction = AVMutableVideoCompositionLayerInstruction(assetTrack: firstTrack)
guard let cor = photoFrameCordinate[i] as? CGRect else{return}
if videoAssetss as! AVURLAsset != firstAsset.last as! AVURLAsset{
firstInstruction.setOpacity(0, at: assetDuration) // asseteDuration
}
let transform = CGAffineTransform(scaleX: 0.4, y:1).concatenating(CGAffineTransform(translationX: trackInstruction[i-1]., y: -cor.origin.y))
firstInstruction.setTransform(transform, at: CMTime.zero)
assetDuration = CMTimeAdd(assetDuration, (videoAssetss as! AVURLAsset).duration)
lastAsset = videoAssetss as? AVURLAsset
trackInstruction.append(firstInstruction)
i += 1
// arrayOfComposition.append(firstTrack)
} catch {
print("Failed to load first track")
return
}
}
// Watermark Effect
let width: CGFloat = widthConstraintViewForImage.constant
let height = heightConstraintViewForImage.constant
let parentlayer = CALayer()
parentlayer.frame = CGRect(x: 0, y: 0, width: width, height: height)
//Mark: Frame layer
let bglayer = CALayer()
bglayer.contents = imgViewForAdminImage.image?.cgImage
bglayer.frame = CGRect(x: 0, y: 0, width: width, height: height)
bglayer.backgroundColor = UIColor.clear.cgColor
for index in 0..<videoURLS.count{
var videoBox = CALayer()
guard let cor = photoFrameCordinate[index] as? CGRect else{return}
videoBox.frame = CGRect(x: cor.origin.x, y: parentlayer.frame.maxY-(cor.origin.y+cor.size.height), width: cor.size.width, height: cor.size.height)
videoBox.backgroundColor = UIColor.green.cgColor
videoBox.masksToBounds = true
var vlayer = CALayer()
vlayer.contentsScale = 1.0
vlayer.contentsGravity = CALayerContentsGravity.center
vlayer.frame = CGRect(x: 0, y: 0, width:cor.size.width, height: cor.size.height)
vlayer.backgroundColor = UIColor.yellow.cgColor
videolayer.append(vlayer)
videoBox.addSublayer(vlayer)
box.append(videoBox)
bglayer.addSublayer(videoBox)
}
parentlayer.addSublayer(bglayer)
let layercomposition = AVMutableVideoComposition()
layercomposition.frameDuration = CMTimeMake(value: 1, timescale: 30)
layercomposition.animationTool = AVVideoCompositionCoreAnimationTool(postProcessingAsVideoLayers: videolayer, in: parentlayer)
// 2.1
mainInstruction.timeRange = CMTimeRangeMake(start: CMTime.zero, duration: assetDuration)
mainInstruction.layerInstructions = trackInstruction
mainInstruction.backgroundColor = UIColor.red.cgColor
layercomposition.instructions = [mainInstruction]
// layercomposition.renderSize = CGSizeMake(videoSize.width * scale, videoSize.height * scale)
layercomposition.renderScale = 1.0
layercomposition.renderSize = CGSize(width: width, height: height)
// create new file to receive data
let dirPaths = NSSearchPathForDirectoriesInDomains(.documentDirectory, .userDomainMask, true)
let docsDir = dirPaths[0] as NSString
let movieFilePath = docsDir.appendingPathComponent("result.mp4")
let movieDestinationUrl = NSURL(fileURLWithPath: movieFilePath)
// use AVAssetExportSession to export video
let assetExport = AVAssetExportSession(asset: mixComposition, presetName:AVAssetExportPresetMediumQuality)
assetExport?.outputFileType = AVFileType.mp4
assetExport?.videoComposition = layercomposition
// Check exist and remove old file
FileManager.default.removeItemIfExisted(movieDestinationUrl as URL)
assetExport?.outputURL = movieDestinationUrl as URL
assetExport?.exportAsynchronously(completionHandler: {
switch assetExport!.status {
case AVAssetExportSession.Status.failed:
print("failed")
print(assetExport?.error ?? "unknown error")
case AVAssetExportSession.Status.cancelled:
print("cancelled")
print(assetExport?.error ?? "unknown error")
default:
print("Movie complete")
PHPhotoLibrary.shared().performChanges({
PHAssetChangeRequest.creationRequestForAssetFromVideo(atFileURL: movieDestinationUrl as URL)
}) { saved, error in
if saved {
print("Saved")
}else{
print(error!)
}
}
self.playVideo()`enter code here`
}
})
}
When I set the opacity of the first video to 0 then the second video is showing in all frames. I think all videos are coming but behind the first video that's why only first video is showing in the all frames.

Answer 1

I used
let videolayerInstruction = AVMutableVideoCompositionLayerInstruction(assetTrack: asset)
videolayerInstruction.setCropRectangle(CGRec(), at: Time())