为什么 imagePickerController.mediaTypes = [kUTTypeMovie as String] 将实时照片作为弹跳或循环效果作为视频？

Question

我使用 UIImagePicker 仅从我的媒体库中选择视频，并将我的媒体类型设置为：

imagePicker.mediaTypes = [kUTTypeMovie as String]

我注意到，当展示库时，即使我希望只有视频，如果库中有具有 Bounce 或 Loop 效果的实时照片，它也会显示。如果我拍摄同一张照片并将其效果切换为 Live 或 Long Exposure，它将不再出现在图库中。如果我将其切换回 Bounce 或 Loop，它会重新出现。

我已经尝试了 .photoLibrary 和 .savedPhotosAlbum，同样的事情发生了。

我问的原因是因为我不想让他们出库，我只想选择 xxx 秒或更长时间的视频。

即使我只选择视频，为什么这些效果类型会出现在图像选择器库中？
为什么只有 Loop 和 Bounce 出现而 Long Exposure 和 Live 没有出现？
如何将它们拒之门外？

也许这是一个单独的问题，但由于它属于相同的 Live 和 Bounce 照片问题，所以我添加了它。我注意到，如果我在 AVPlayer 中放置从 Live 或 Bounce 照片派生的 url，如果我进入后台并返回，当应用程序出现时会短暂冻结回到前台，它只发生在这 2 个效果（不应该可用）。当应用程序进入后台时，我使用此方法正确删除了 AVPlayerLayer，但当播放器内部初始化来自那些效果类型的 url 时，它仍然在前台短暂冻结（应用程序无响应） .

代码：

import MobileCoreServices
import AVFoundation

class ViewController: UIImagePickerControllerDelegate, UINavigationControllerDelegate{

var playerItem: AVPlayerItem?
var player: AVPlayer?
var playerLayer: AVPlayerLayer?
var currentPlayTime: CMTime?
let imagePicker = UIImagePickerController()

override func viewDidLoad() {
    super.viewDidLoad()

    imagePickerController.delegate = self

    NotificationCenter.default.addObserver(self, selector: #selector(appHasEnteredBackground), name: Notification.Name.UIApplicationWillResignActive, object: nil)

    NotificationCenter.default.addObserver(self, selector: #selector(appWillEnterForeground), name: Notification.Name.UIApplicationWillEnterForeground, object: nil)
}

override func viewDidLayoutSubviews() {
    // I have a UIView Outlet for the AVPlayerLayer named viewForPlayerLayer.

    guard let playerLayer = playerLayer else { return }
    playerLayer.videoGravity = .resizeAspectFill
    viewForPlayerLayer.layer.insertSublayer(playerLayer, at: 0)
    playerLayer.frame = viewForPlayerLayer.bounds
    playerLayer.masksToBounds = true

}

@IBAction fileprivate func showLibraryButtonTapped(_ sender: UIButton) {

    imagePicker.sourceType = UIImagePickerControllerSourceType.photoLibrary // .savedPhotosAlbum also tried 
    imagePicker.mediaTypes = [kUTTypeMovie as String]
    imagePicker.videoMaximumDuration = 60
    present(imagePicker, animated: true, completion: nil)
}

func imagePickerController(_ picker: UIImagePickerController, didFinishPickingMediaWithInfo info: [String : Any]) {

    if let url = info[UIImagePickerControllerMediaURL] as? URL{

          let asset = AVAsset(url: url)
          playerItem = AVPlayerItem(asset: asset)
          player = AVPlayer(playerItem: playerItem!)
          playerLayer = AVPlayerLayer(player: player)
          player?.play()
    }
    imagePicker.dismiss(animated: true, completion: nil)
}

func imagePickerControllerDidCancel(_ picker: UIImagePickerController) {
    imagePicker.dismiss(animated: true, completion: nil)
}

@objc fileprivate func appHasEnteredBackground() {

    currentPlayTime = player.currentTime()

    if player.isPlaying{
        player.pause()
    }

    playerLayer = nil
}

@objc fileprivate func appWillEnterForeground(){

    if let player = player, let currentPlayTime = currentPlayTime{

        playerLayer = AVPlayerLayer(player: player)

        player.seek(to: currentPlayTime, toleranceBefore: kCMTimeZero, toleranceAfter: kCMTimeZero)
    }
}

}

Answer 1

如果您要求显示视频，则无法阻止 loop/bounce 实时照片视频出现在选择器中，因为它们是视频。但是，如果用户选择一个，您可以在委托方法中检测到一个。为此，UIImagePickerControllerMediaType 不足以 fine-grained。相反，获取照片库授权并获取由 UIImagePickerControllerPHAsset 键返回的 PHAsset，并检查其 playbackStyle。这样就能画出你想要的区别了。

https://developer.apple.com/documentation/photos/phasset.playbackstyle

.videoLooping 是反弹或缩放实时照片。

为什么 imagePickerController.mediaTypes = [kUTTypeMovie as String] 将实时照片作为弹跳或循环效果作为视频？

Why is imagePickerController.mediaTypes = [kUTTypeMovie as String] including Live Photos as Bounce or Loop Effect as Video?

uiimagepickercontroller

ios

avplayer

swift

uiimagepickercontrollermediatype