如何在AVVideoComposition中玩AVPlayer？

Question

大家好，我一直在创建一个iOS视频编辑应用程序。我已经创建了一个由两个layers.now组成的AVVideoComposition，我想在AVPlayer.as中播放这个组合，AVVideoComposition不是一个资产，所以我如何在AVPlayer中发挥这个功能呢？下面是我一直在尝试的示例代码，我听说过AVVideoCompositionCoreAnimation，但这也不起作用。

let backgroundLayer = CoverView.layer
let videoLayer = VideoView.layer
let parentLayer = CALayer()
    parentLayer.frame = CGRect(x:20.0 , y: 20.0, width: CoverView.frame.width, height: CoverView.frame.height)
    parentLayer.addSublayer(backgroundLayer)
    parentLayer.addSublayer(videoLayer)


    let composition = AVMutableVideoComposition()

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

Answer 1

您可以在AVPlayer中加入AVPlayerItem，这允许将组合作为输入，这样就可以不导出就可以播放。

let item = AVPlayerItem(asset: composition)
let player = AVPlayer(playerItem: item)

Answer 2

您需要一个用于this.in AVExportSession的导出方法，有一个方法导出了finish.in，这个方法可以为您的视频file.like生成一个url

func exportDidFinish(_ session: AVAssetExportSession) {

     guard
        session.status == AVAssetExportSession.Status.completed,
        let outputURL = session.outputURL
        else {
          return
      }

        self.avplayer = AVPlayer(url: outputURL)

               playerController.player = self.avplayer
               self.addChild(playerController)
               view.addSubview(playerController.view)
               playerController.view.frame = view.bounds
               playerController.showsPlaybackControls = false
              avplayer.isMuted = false

Answer 3

你可以玩AVMutableComposition，但不能玩AVMutableVideoComposition。但是您可以使用AVMutableVideoComposition作为AVPlayerItem的videoComposition属性。

let composition = AVMutableComposition()
    
//add and configure tracks here    

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

let item = AVPlayerItem(asset: composition)
item.videoComposition = videoComposition
let player = AVPlayer(playerItem: item)