我可以在相机胶卷上获取视频的绝对 URI 并从我的应用程序中对其进行变异吗？

Question

我想对 iphone 相机胶卷中的视频执行操作，我需要一个绝对 URI，因为我将在我的应用程序中本地使用 ffmpeg。

是否可以对视频进行原地操作？还是我需要将视频复制到 tmp 目录，对其进行操作，然后写回相机胶卷？

Answer 1

如果您已经获取资产，并尝试使用 PHFetchResult 对象：

var video = PHAsset() // the video to be edited

…

 if video.canPerform(.content) {  // check if the selected PHAsset can be edited

  video.requestContentEditingInput(with: nil, completionHandler: { editingInput, _ in

  let videoAsset = editingInput?.audiovisualAsset // get tracks and metadata of the video and start editing
  let videoURL = (videoAsset as? AVURLAsset)?.url // This might be nil so better use videoAsset

        /*
         Start editing your video here


        */

  guard let input = editingInput else { return }
  let output = PHContentEditingOutput(contentEditingInput: input)
  let outputURL = output.renderedContentURL // URL at which you write/export the edited video, it must be a .mov file
  let editedVideo = NSData()  // suppose your video fileName is editedVideo.mov, I used NSData since I don't know what final edited object will be.
  editedVideo.write(to: outputURL, atomically: false)

  PHPhotoLibrary.shared().performChanges({
  let changeRequest = PHAssetChangeRequest(for: video)
  changeRequest.contentEditingOutput = output
               })
            })

        }

或者如果您使用默认的 imagePicker，我们可以使用以下方法获取 tmp 视频 url：

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

    let videoURL = info[UIImagePickerController.InfoKey.mediaURL] as! NSURL
    print(videoURL)  // file is already in tmp folder


     let video = info[UIImagePickerController.InfoKey.phAsset] as! PHAsset
        // implement the above code using this PHAsset 

   // your will still need to request photo library changes, and save the edited video and/or delete the older one

    }

Answer 2

我在我的项目中实现了类似的东西，希望它能对你有所帮助。

我在集合视图中显示所有项目并对选择执行操作，您还可以获得所选视频的 url

func getVideoFromCameraRoll() {
    let options = PHFetchOptions()
    options.sortDescriptors = [ NSSortDescriptor(key: "creationDate", ascending: false) ]
    options.predicate = NSPredicate(format: "mediaType = %d", PHAssetMediaType.video.rawValue)
    videos = PHAsset.fetchAssets(with: options)
    videoLibraryCV.reloadData()
}

func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
    return videos.count
}

func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
    let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "Cell", for: indexPath)
    let asset = videos!.object(at: indexPath.row)
    let width: CGFloat = 150
    let height: CGFloat = 150
    let size = CGSize(width:width, height:height)
    cell.layer.borderWidth = 0.5
    cell.layer.borderColor = UIColor.lightGray.cgColor
    PHImageManager.default().requestImage(for: asset, targetSize: size, contentMode: PHImageContentMode.aspectFit, options: nil)
    {   (image, userInfo) -> Void in

        let imageView = cell.viewWithTag(1) as! UIImageView
        imageView.image = image

        let labelView = cell.viewWithTag(2) as! UILabel
        labelView.text = String(format: "%02d:%02d",Int((asset.duration / 60)),Int(asset.duration) % 60)
    }
    return cell
}

func collectionView(collectionView: UICollectionView, didSelectItemAtIndexPath indexPath: NSIndexPath) {
 let asset = photos!.object(at: indexPath.row)
 guard(asset.mediaType == PHAssetMediaType.Video)
 else {
  print("Not a valid video media type")
  return
 }

 PHCachingImageManager().requestAVAssetForVideo(asset, options: nil, resultHandler: {
  (asset: AVAsset ? , audioMix : AVAudioMix ? , info : [NSObject: AnyObject] ? ) in
  let asset = asset as!AVURLAsset
  print(asset.URL) // Here is video URL
 })

}

希望对你有用...:)

Answer 3

我已经阅读了一些文档和教程，并根据该研究回答了以下问题。

是否可以对视频进行原地操作？

Yes (By copying it to temp dir) and No (to the original location where the video is actually stored)

看看下面的图片并引用 official docs

Using PhotoKit, you can fetch and cache assets for display and playback, edit image and video content or manage collections of assets such as albums, Moments, and Shared Albums.

我们无法直接访问 image/video 的存储位置，而是使用 PHAsset and Asset objects are immutable so we can't perform operations directly on it. We would need PHAssetChangeRequest 获取原始数据或表示来创建、删除、更改元数据或编辑照片资产的内容。

是否需要将视频复制到临时目录，对其进行操作，然后写回相机胶卷？

Yep, that's the way to go.

我可以在相机胶卷上获取视频的绝对 URI 并从我的应用程序中对其进行变异吗？

Can I get absolute URI of video on camera roll and mutate it from my app?

video

image

ios

camera-roll

swift