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Deserialization

Restoring a settings file#

To restore an editor instance to a previous state, we load the saved instance as serialized settings from our main bundle and wrap it in a Data object. It would, of course, also be possible to make a request and load these settings from a remote URL (compare Open Video from Remote URL).

The deserialize method of the Deserializer class takes those serialized settings as an argument and returns a result set that exposes an PhotoEditModel instance. This photoEditModel is then used to initialize a new VideoEditViewController instance alongside some video to which the edits will be applied.

Note that if you are unsure whether the aspect ratio of the video that the serialized settings are applied to match the video that they are derived from, you should pass the video's dimensions explicitly to the deserializer. This ensures that all dimensions and positions are matched as expected.

import UIKit
import VideoEditorSDK


class VideoDeserializationSwift: Example, VideoEditViewControllerDelegate {
  override func invokeExample() {
    // Create a `Video` from a URL to a video in the app bundle.
    let video = Video(url: Bundle.main.url(forResource: "Skater", withExtension: "mp4")!)


    // Create a default `Configuration` with default `AssetCatalog`.
    let configuration = Configuration { builder in
      builder.assetCatalog = AssetCatalog.defaultItems
    }


    // Load the serialized settings from the app bundle. You could also load this from a remote URL for example.
    // See `OpenVideoFromRemoteURLSwift` to get an idea about the approach to take for this.
    let serializedSettings = try? Data(contentsOf: Bundle.main.url(forResource: "video_serialization", withExtension: "json")!)


    // Deserialize the serialized settings. If you're not sure that the aspect ratio of the current video and the
    // video used when creating the serialized settings are identical, you should specify the size of the video to
    // apply the edits on.
    let deserializationResult = Deserializer.deserialize(data: serializedSettings!, imageDimensions: video.size, assetCatalog: configuration.assetCatalog)


    // Get the `PhotoEditModel` from the deserialization result.
    let photoEditModel = deserializationResult.model!


    // Create and present the video editor. Make this class the delegate of it to handle export and cancelation.
    // Pass the deserialized `PhotoEditModel` to the editor.
    let videoEditViewController = VideoEditViewController(videoAsset: video, configuration: configuration, photoEditModel: photoEditModel)
    videoEditViewController.delegate = self
    videoEditViewController.modalPresentationStyle = .fullScreen
    presentingViewController?.present(videoEditViewController, animated: true, completion: nil)


    // For saving edits, please take a look at `VideoSerializationSwift`.
  }


  // MARK: - VideoEditViewControllerDelegate


  func videoEditViewControllerShouldStart(_ videoEditViewController: VideoEditViewController, task: VideoEditorTask) -> Bool {
    // Implementing this method is optional. You can perform additional validation and interrupt the process by returning `false`.
    true
  }


  func videoEditViewControllerDidFinish(_ videoEditViewController: VideoEditViewController, result: VideoEditorResult) {
    // The user exported a new video successfully and the newly generated video is located at `result.output.url`. Dismissing the editor.
    presentingViewController?.dismiss(animated: true, completion: nil)
  }


  func videoEditViewControllerDidFail(_ videoEditViewController: VideoEditViewController, error: VideoEditorError) {
    // There was an error generating the video.
    print(error.localizedDescription)
    // Dismissing the editor.
    presentingViewController?.dismiss(animated: true, completion: nil)
  }


  func videoEditViewControllerDidCancel(_ videoEditViewController: VideoEditViewController) {
    // The user tapped on the cancel button within the editor. Dismissing the editor.
    presentingViewController?.dismiss(animated: true, completion: nil)
  }
}