Инициализация AVAssest с URL из адаптивных форматов YouTube требует времени для загрузки видео

Question

AVasset требует времени для загрузки (только для видеоформатов). Но простые форматы не требуют времени (объединены видео и аудио). Эта проблема была даже воспроизведена в AVPlayer (url: URL (строка: * URL, полученный с YouTube api / as! String)!) *

func mergeFilesWithUrl(videoUrl:URL, audioUrl:URL, completion: @escaping (Bool) -> (Void))
    {  
       let mixComposition : AVMutableComposition = AVMutableComposition()
        var mutableCompositionVideoTrack : [AVMutableCompositionTrack] = []
        var mutableCompositionAudioTrack : [AVMutableCompositionTrack] = []
        let totalVideoCompositionInstruction : AVMutableVideoCompositionInstruction = AVMutableVideoCompositionInstruction()

        let aVideoAsset : AVAsset = AVAsset(url: videoUrl) //Here is the issue
        let key = "playable"
        DispatchQueue.main.async {
            aVideoAsset.loadValuesAsynchronously(forKeys: [key], completionHandler: {
                let status = aVideoAsset.statusOfValue(forKey: key, error: nil)
                if status == AVKeyValueStatus.loaded {

                    let aAudioAsset : AVAsset = AVAsset(url: audioUrl)
                    aAudioAsset.loadValuesAsynchronously(forKeys: [key], completionHandler: {
                        let status1 = aAudioAsset.statusOfValue(forKey: key, error: nil)
                        if status1 == AVKeyValueStatus.loaded {

                            mutableCompositionVideoTrack.append(mixComposition.addMutableTrack(withMediaType: AVMediaType.video, preferredTrackID: kCMPersistentTrackID_Invalid)!)
                            mutableCompositionAudioTrack.append( mixComposition.addMutableTrack(withMediaType: AVMediaType.audio, preferredTrackID: kCMPersistentTrackID_Invalid)!)

                            let aVideoAssetTrack : AVAssetTrack = aVideoAsset.tracks(withMediaType: AVMediaType.video)[0]
                            let aAudioAssetTrack : AVAssetTrack = aAudioAsset.tracks(withMediaType: AVMediaType.audio)[0]

                            do{
                                try mutableCompositionVideoTrack[0].insertTimeRange(CMTimeRangeMake(kCMTimeZero, aVideoAssetTrack.timeRange.duration), of: aVideoAssetTrack, at: kCMTimeZero)

                                try mutableCompositionAudioTrack[0].insertTimeRange(CMTimeRangeMake(kCMTimeZero, aAudioAssetTrack.timeRange.duration), of: aAudioAssetTrack, at: kCMTimeZero)
                            } catch{

                            }

                            totalVideoCompositionInstruction.timeRange = CMTimeRangeMake(kCMTimeZero,aVideoAssetTrack.timeRange.duration )

                            let mutableVideoComposition : AVMutableVideoComposition = AVMutableVideoComposition()
                            mutableVideoComposition.frameDuration = CMTimeMake(1, 30)

                            mutableVideoComposition.renderSize = CGSize(width: 1280,height: 720)

                            self.mixComposition = mixComposition
                            _ = completion(true)
                        }
                    })
                }
            })
        }
    }