Преобразование CMSampleBuffer в .mov во время трансляции с помощью ReplayKit

Этот код работает для меня, но помимо моего каталога в группах приложений мне пришлось использовать PHPhotoLibrary. Каталог групп приложений — не единственный способ создать файл, вы можете использовать любой каталог, какой захотите. Я надеюсь, что это может помочь кому-то.

import ReplayKit
import Photos

class SampleHandler: RPBroadcastSampleHandler {
    
    let appIdentifier = "group.CY"
    let fileManager = FileManager.default
    
    var videoWriterInput: AVAssetWriterInput!
    var microphoneWriterInput: AVAssetWriterInput!
    
    var videoWriter: AVAssetWriter!
    
    var sessionBeginAtSourceTime: CMTime!
    
    var isRecording = false
    
    var outputFileLocation: URL!
    
    override func broadcastStarted(withSetupInfo setupInfo: [String : NSObject]?) {
        guard !isRecording else { return }
        isRecording = true
        sessionBeginAtSourceTime = nil
        setUpWriter()
    }
    
    func setUpWriter() {
        let width = UIScreen.main.bounds.width * 2
        let height = UIScreen.main.bounds.height * 2
        
        self.outputFileLocation = videoFileLocation()
        
        // Add the video input
        videoWriter = try? AVAssetWriter.init(outputURL: self.outputFileLocation, fileType: AVFileType.mp4)
        let videoCompressionPropertys = [
            AVVideoAverageBitRateKey: width * height * 10.1
        ]
        
        let videoSettings: [String: Any] = [
            AVVideoCodecKey: AVVideoCodecType.h264,
            AVVideoWidthKey: width,
            AVVideoHeightKey: height,
            AVVideoCompressionPropertiesKey: videoCompressionPropertys
        ]
        
        videoWriterInput = AVAssetWriterInput(mediaType: AVMediaType.video, outputSettings: videoSettings)
        videoWriterInput.expectsMediaDataInRealTime = true
        
        // Add the microphone input
        var acl = AudioChannelLayout()
        memset(&acl, 0, MemoryLayout<AudioChannelLayout>.size)
        acl.mChannelLayoutTag = kAudioChannelLayoutTag_Mono;
        let audioOutputSettings: [String: Any] =
            [ AVFormatIDKey: kAudioFormatMPEG4AAC,
              AVSampleRateKey : 44100,
              AVNumberOfChannelsKey : 1,
              AVEncoderBitRateKey : 64000,
              AVChannelLayoutKey : Data(bytes: &acl, count: MemoryLayout<AudioChannelLayout>.size)]
        
        microphoneWriterInput = AVAssetWriterInput(mediaType: AVMediaType.audio, outputSettings: audioOutputSettings)
        microphoneWriterInput.expectsMediaDataInRealTime = true
        
        if videoWriter.canAdd(videoWriterInput) {
            videoWriter.add(videoWriterInput)
        }
        
        if videoWriter.canAdd(microphoneWriterInput) {
            videoWriter.add(microphoneWriterInput)
        }
        
        videoWriter.startWriting()
    }
    
    override func broadcastFinished() {
        guard isRecording else { return }
        isRecording = false
        sessionBeginAtSourceTime = nil
        
        let dispatchGroup = DispatchGroup()
        dispatchGroup.enter()
        
        videoWriterInput.markAsFinished()
        microphoneWriterInput.markAsFinished()
        
        var finishedWriting = false
        videoWriter.finishWriting {
            PHPhotoLibrary.shared().performChanges({
                PHAssetCollectionChangeRequest.creationRequestForAssetCollection(withTitle: "xxx")
                
                PHAssetChangeRequest.creationRequestForAssetFromVideo(atFileURL: self.outputFileLocation)
            }) { completed, error in
                if completed {
                    NSLog("Video \(self.outputFileLocation.path ?? "") has been moved to camera roll")
                }
                
                if error != nil {
                    NSLog("ERROR:::Cannot move the video \(self.outputFileLocation.path ?? "") to camera roll, error: \(error!.localizedDescription)")
                }
                
                finishedWriting = true
            }
            
            while finishedWriting == false {
                //          NSLog("DEBUG:::Waiting to finish writing...")
            }
            
            dispatchGroup.leave()
        }
        
        dispatchGroup.wait() // <= blocks the thread here
    }
    
    override func finishBroadcastWithError(_ error: Error) {
        let e = error
        print(e)
    }
    
    override func processSampleBuffer(_ sampleBuffer: CMSampleBuffer, with sampleBufferType: RPSampleBufferType) {
        let writable = canWrite()
        
        if writable, sessionBeginAtSourceTime == nil {
            sessionBeginAtSourceTime = CMSampleBufferGetPresentationTimeStamp(sampleBuffer)
            videoWriter.startSession(atSourceTime: sessionBeginAtSourceTime!)
        }
        
        if writable {
            switch sampleBufferType {
            case .video:
                if videoWriterInput.isReadyForMoreMediaData {
                    videoWriterInput.append(sampleBuffer)
                }
            case .audioApp:
                print("audio")
            case .audioMic:
                if microphoneWriterInput.isReadyForMoreMediaData {
                    microphoneWriterInput.append(sampleBuffer)
                }
            @unknown default:
                print("unknown")
            }
        }
    }
    
    func videoFileLocation() -> URL {
        let documentsPath = fileManager.containerURL(forSecurityApplicationGroupIdentifier: appIdentifier)!
        let videoOutputUrl = documentsPath
            .appendingPathComponent("Library")
            .appendingPathComponent("Caches")
            .appendingPathComponent("mobile")
            .appendingPathExtension("mp4")
        do {
            if fileManager.fileExists(atPath: videoOutputUrl.path) {
                try fileManager.removeItem(at: videoOutputUrl)
            }
        } catch { print(error) }
        
        return videoOutputUrl
    }
    
    func canWrite() -> Bool {
        return videoWriter != nil && isRecording && videoWriter?.status == .writing
    }
}