Cannot export the video to play in full screen

[rjt3662]

I'm recording video using AVCaptureMovieFileOutput and passing the file URL given by AVCaptureMovieFileOutput to NextLevelSessionExporter instance.
I'm trying to export the video in a way that it takes up the whole device's screen to display video. It is working into the app, when I play the exported video using AVPreviewLayer it plays in full screen and takes up the whole device screen but as soon as I export the video into gallery then playing from gallery it does not plays into full screen and have black stripes above and below.
Basically, I want to do just like snapchat does, when we save a snap-video from snapchat it is being played into full screen from gallery.

func fileOutput(_ output: AVCaptureFileOutput, didFinishRecordingTo outputFileURL: URL, from connections: [AVCaptureConnection], error: Error?) {
        if let err = error as NSError?, err.code != -11810 { //-11810 = recording stopped when timelimit reached
            print("Error recording movie: \(err)")
        } else {
            let asset = AVAsset(url: outputFileURL)
            let exporter = NextLevelSessionExporter(withAsset: asset)
            exporter.outputFileType = AVFileType.mp4
            let tmpURL = URL(fileURLWithPath: NSTemporaryDirectory(), isDirectory: true)
                .appendingPathComponent(ProcessInfo().globallyUniqueString)
                .appendingPathExtension("mp4")
            exporter.outputURL = tmpURL

            let compressionDict: [String: Any] = [
                AVVideoAverageBitRateKey: NSNumber(integerLiteral: 1100000),
                AVVideoProfileLevelKey: AVVideoProfileLevelH264HighAutoLevel as String,
            ]
            let videoTrack = asset.tracks(withMediaType: .video).first
            exporter.videoOutputConfiguration = [
                AVVideoCodecKey: AVVideoCodecType.h264,
                AVVideoWidthKey: NSNumber(integerLiteral: Int(videoTrack?.naturalSize.height ?? 1080)),
                AVVideoHeightKey: NSNumber(integerLiteral: Int(videoTrack?.naturalSize.width ?? 1920)),
                AVVideoScalingModeKey: AVVideoScalingModeResizeAspectFill,
                AVVideoCompressionPropertiesKey: compressionDict
            ]
            exporter.audioOutputConfiguration = [
                AVFormatIDKey: kAudioFormatMPEG4AAC,
                AVEncoderBitRateKey: NSNumber(integerLiteral: 128000),
                AVNumberOfChannelsKey: NSNumber(integerLiteral: 2),
                AVSampleRateKey: NSNumber(value: Float(44100))
            ]

            exporter.export(progressHandler: { (progress) in
                print(progress)
            }, completionHandler: { [weak self] result in
                guard let self = self else { return }
                switch result {
                case .success(let status):
                    switch status {
                    case .completed:
                        print("NextLevelSessionExporter, export completed, \(exporter.outputURL?.description ?? "")")
                        break
                    default:
                        print("NextLevelSessionExporter, did not complete")
                        break
                    }
                    break
                case .failure(let error):
                    print("NextLevelSessionExporter, failed to export \(error)")
                    break
                }
            })
            
        }
    }

[piemonte]

hey @rjt3662 thanks for the project interest. to give you some tips, i recommend decoupling "playing fullscreen" from exporting the video to another format. It seems like you may be exporting the video at a small size:

            AVVideoWidthKey: NSNumber(integerLiteral: Int(videoTrack?.naturalSize.height ?? 1080)),
            AVVideoHeightKey: NSNumber(integerLiteral: Int(videoTrack?.naturalSize.width ?? 1920)),

If you just use 1080 x 1920 instead to ensure you have a large video, if that's what you want.

Next, I recommend ensuring your video player is using aspectfit, then you should be good.