Swift 3：AVVideoCompositionCoreAnimationToolでビデオにウォーターマークを付ける問題

Question

次のコードは、AVVideoCompositionCoreAnimationToolでビデオにロゴとテキストを追加するために完全に機能していました。それからSwift 3がやってきた！時にはビデオがロゴとテキストで表示されることがあり、エクスポートされたときにビデオが表示されないことがあります。

let videoComposition: AVMutableVideoComposition = AVMutableVideoComposition() 

    videoComposition.frameDuration = CMTimeMake(1, 60) 
    videoComposition.renderSize = CGSize(width: clipVideoTrack.naturalSize.height, height: clipVideoTrack.naturalSize.height) 


    let instruction: AVMutableVideoCompositionInstruction = AVMutableVideoCompositionInstruction() 

    instruction.timeRange = CMTimeRangeMake(kCMTimeZero, CMTimeMakeWithSeconds(60, 30)) 

    // transformer is applied to set the video in portrait otherwise it is rotated by 90 degrees 
    let transformer: AVMutableVideoCompositionLayerInstruction = 
     AVMutableVideoCompositionLayerInstruction(assetTrack: clipVideoTrack) 

    let t1: CGAffineTransform = CGAffineTransform(translationX: clipVideoTrack.naturalSize.height, y: -(clipVideoTrack.naturalSize.width - clipVideoTrack.naturalSize.height)/2) 

    let t2: CGAffineTransform = t1.rotated(by: CGFloat(M_PI_2)) 

    var finalTransform: CGAffineTransform = t2 

    transformer.setTransform(finalTransform, at: kCMTimeZero) 

    instruction.layerInstructions = NSArray(object: transformer) as! [AVVideoCompositionLayerInstruction] 

    videoComposition.instructions = NSArray(object: instruction) as! [AVVideoCompositionInstructionProtocol] 



    let mixComposition = AVMutableComposition() 
    let compositionVideoTrack = mixComposition.addMutableTrack(withMediaType: AVMediaTypeVideo, preferredTrackID: kCMPersistentTrackID_Invalid) 


    do { 
     try compositionVideoTrack.insertTimeRange(CMTimeRangeMake(kCMTimeZero, asset.duration), of: clipVideoTrack, at: kCMTimeZero) 
    } catch { 
     print(error) 
    } 


    //Add watermark 


    let myImage = UIImage(named: "logo") 

    let aLayer = CALayer() 
    aLayer.contents = myImage!.cgImage 
    aLayer.frame = CGRect(x: (clipVideoTrack.naturalSize.height*(self.view.bounds.width-45))/self.view.bounds.width, y: (clipVideoTrack.naturalSize.height*(self.view.bounds.width-40))/self.view.bounds.width, width: (clipVideoTrack.naturalSize.height*40)/self.view.bounds.width, height: (clipVideoTrack.naturalSize.height*40)/self.view.bounds.width) 

    let titleLayer = CATextLayer() 
    titleLayer.string = "text" 
    titleLayer.font = UIFont(name: "helvetica", size: 0) 
    titleLayer.fontSize = clipVideoTrack.naturalSize.height/16 
    titleLayer.shadowOpacity = 0.5 
    titleLayer.alignmentMode = kCAAlignmentCenter 
    titleLayer.frame = CGRect(x: 0, y: 0, width: clipVideoTrack.naturalSize.height, height: clipVideoTrack.naturalSize.height/6) 
    titleLayer.display() 


    let videoSize = asset.tracks(withMediaType: AVMediaTypeVideo)[0].naturalSize 
    let parentLayer = CALayer() 
    let videoLayer = CALayer() 
    parentLayer.frame = CGRect(x: 0, y: 0, width: videoSize.height, height: videoSize.height) 
    videoLayer.frame = CGRect(x: 0, y: 0, width: videoSize.height, height: videoSize.height) 

    parentLayer.addSublayer(videoLayer) 
    parentLayer.addSublayer(aLayer) 
    parentLayer.addSublayer(titleLayer) 


    videoComposition.animationTool = AVVideoCompositionCoreAnimationTool(postProcessingAsVideoLayer: videoLayer, in: parentLayer) 



    do { try FileManager.default.removeItem(at: filePath) } 
    catch let error as NSError { 
     NSLog("\(error), \(error.localizedDescription)") 
    } 



    var exportUrl: URL = filePath 
    self.videoUrl = filePath as NSURL 


    var exporter = AVAssetExportSession(asset: asset, presetName: AVAssetExportPresetMediumQuality) 

    exporter!.videoComposition = videoComposition 
    exporter!.outputFileType = AVFileTypeQuickTimeMovie 
    exporter!.outputURL = URL(fileURLWithPath: exportUrl.path) 


    exporter!.exportAsynchronously(completionHandler: { 

     DispatchQueue.main.async { 


      self.view.layer.addSublayer(self.avPlayerLayer) 

      let item = AVPlayerItem(url: exportUrl) 
      self.player.replaceCurrentItem(with: item) 

      if (self.player.currentItem != nil) { 
       print("Starting playback!") 
       self.player.play() 
      } 

     } 

    }) 

これは以前のバージョンのSwiftと完全に機能していましたが、すぐには動作しませんでした。

注記：私がvideoComposition.animationTool = AVVideoCompositionCoreAnimationTool(postProcessingAsVideoLayer: videoLayer, in: parentLayer)をコメントアウトすると、ビデオはエクスポートされ、オーバータイムでオーバーレイは正常に再生されます。

Answer 1

コードはiOS 9で動作していますが、これはおそらくa bug in iOS 10.0です。videoCompositionが設定されていると、AVAssetExportSessionsが正しく動作しません。

iOS 10.1 betaで状況が良く、その他にworked around the problemが表示されているとの報告があります。