AVFoundation -Videos merge but only last video plays - ios

Question

I have an array of [AVAsset](). Whenever I record different videos at different durations the below code merges all the durations into 1 video but it will only play the last video in a loop.
For eg. video1 is 1 minute and shows a dog walking, video2 is 1 minute and shows a bird flying, video3 is 1 minute and shows a horse running. The video will merge and play for 3 minutes but it will only show the horse running for 1 minute each three consecutive times.
Where am I going wrong at?
var movieFileOutput = AVCaptureMovieFileOutput()
var arrayVideos = [AVAsset]()
var videoFileUrl: URL?
// button to record video
#objc func recordButtonTapped() {
// Stop recording
if movieFileOutput.isRecording {
movieFileOutput.stopRecording()
print("Stop Recording")
} else {
// Start recording
movieFileOutput.connection(with: AVMediaType.video)?.videoOrientation = videoOrientation()
movieFileOutput.maxRecordedDuration = maxRecordDuration()
videoFileUrl = URL(fileURLWithPath: videoFileLocation())
if let videoFileUrlFromCamera = videoFileUrl {
movieFileOutput.startRecording(to: videoFileUrlFromCamera, recordingDelegate: self)
}
}
}
func videoFileLocation() -> String {
return NSTemporaryDirectory().appending("videoFile.mov")
}
// button to save the merged video
#objc func saveButtonTapped() {
mergeVids()
}
// function to merge and save videos
func mergeVids() {
let mixComposition = AVMutableComposition()
let compositionVideoTrack = mixComposition.addMutableTrack(withMediaType: .video,
preferredTrackID: Int32(kCMPersistentTrackID_Invalid))
compositionVideoTrack?.preferredTransform = CGAffineTransform(rotationAngle: .pi / 2)
let soundtrackTrack = mixComposition.addMutableTrack(withMediaType: .audio,
preferredTrackID: Int32(kCMPersistentTrackID_Invalid))
var insertTime = CMTime.zero
for videoAsset in arrayVideos {
do {
try compositionVideoTrack?.insertTimeRange(CMTimeRangeMake(start: CMTime.zero,
duration: videoAsset.duration),
of: videoAsset.tracks(withMediaType: .video)[0],
at: insertTime)
try soundtrackTrack?.insertTimeRange(CMTimeRangeMake(start: CMTime.zero,
duration: videoAsset.duration),
of: videoAsset.tracks(withMediaType: .audio)[0],
at: insertTime)
insertTime = CMTimeAdd(insertTime, videoAsset.duration)
} catch let error as NSError {
print("\(error.localizedDescription)")
}
}
let outputFileURL = URL(fileURLWithPath: NSTemporaryDirectory() + "merge.mp4")
let path = outputFileURL.path
if FileManager.default.fileExists(atPath: path) {
try! FileManager.default.removeItem(atPath: path)
}
let exporter = AVAssetExportSession(asset: mixComposition, presetName: AVAssetExportPresetHighestQuality)
exporter!.outputURL = outputFileURL
exporter!.outputFileType = AVFileType.mp4
exporter!.shouldOptimizeForNetworkUse = true
exporter!.exportAsynchronously { [weak self] in
let cameraVideoURL = exporter!.outputURL!
PHPhotoLibrary.shared().performChanges({
PHAssetChangeRequest.creationRequestForAssetFromVideo(atFileURL: cameraVideoURL)
}) { (saved, error) in
if let error = error { return }
if !saved { return }
// url is saved
self?.videoFileUrl = nil
self?.arrayVideos.removeAll()
}
}
}
// AVCaptureFileOutputRecording Delegates
func fileOutput(_ output: AVCaptureFileOutput, didStartRecordingTo fileURL: URL, from connections: [AVCaptureConnection]) {
print("+++++++++++++++Started")
print("*****Started recording: \(fileURL)\n")
}
func fileOutput(_ output: AVCaptureFileOutput, didFinishRecordingTo outputFileURL: URL, from connections: [AVCaptureConnection], error: Error?) {
if error == nil {
let asset = AVAsset(url: outputFileURL)
arrayVideos.append(asset)
print(arrayVideos.count)
} else {
print("Error recording movie: \(error!.localizedDescription)")
}
func cleanUp() {
let path = outputFileURL.path
if FileManager.default.fileExists(atPath: path) {
do {
try FileManager.default.removeItem(atPath: path)
} catch {
print("Could not remove file at url: \(outputFileURL)")
}
}
}
}
func captureOutput(_ output: AVCaptureOutput, didOutput sampleBuffer: CMSampleBuffer, from connection: AVCaptureConnection) {
print("++++++Frame Drop: \(connection.description)")
}

Answer 1

Thanks to #alxlives for testing out the merge function and pointing out that since it was fine on his machine the problem must've been somewhere else.
The problem was here:
func videoFileLocation() -> String {
return NSTemporaryDirectory().appending("videoFile.mov")
}
In the recordButtonTapped when it used the above code it kept using the same "videoFile.mov" extension:
videoFileUrl = URL(fileURLWithPath: videoFileLocation()) // <<< it gets called here every time a new video runs
if let videoFileUrlFromCamera = videoFileUrl {
movieFileOutput.startRecording(to: videoFileUrlFromCamera, recordingDelegate: self)
}
To fix it I needed to make each extension unique:
func videoFileLocation() -> String {
let uuid = UUID().uuidString
return NSTemporaryDirectory().appending("videoFile_\(uuid).mov")
}