"The file couldn’t be opened because you don’t have permission to view it." for iCloud Videos

Question

it has been a couple of days, I am struggling with this issue. I am taking a video from photo library and using it to create a thumbnail image. My code is working properly and I am getting the video data and thumbnail for local videos.

But when I select a video that is in iCloud, I am getting the video data but can't create thumbnail.
let img = try assetImgGenerate.copyCGImage(at: time, actualTime: nil) .
returns error: The file couldn't be opened because you don't have permission to view it.

I have found similar questions here, like this one, but the solution was for it is to turn of sand box under capabilities(Which I didn't find in my xcode 12). Tried this one too, I got same error. All other similar questions are for files outside app sandbox, but mine is a video from photo library. Shouldn't I be able to access it within my app?. Below is my code. please help.

let options = PHVideoRequestOptions()
 options.isNetworkAccessAllowed = true
 options.progressHandler = {  (progress, error, stop, info) in
   print("progress: \(progress)")
 }

 //phAsset is asset fetched from photo library
 PHImageManager.default().requestAVAsset(forVideo: phAsset, options: options) 
 {(avAsset, mix, info) in

   let myAsset = avAsset as? AVURLAsset
   do {
    if let url = myAsset?.url{
        let videoData = try Data(contentsOf:url)
        DispatchQueue.global(qos: .background).async {
            let assetImgGenerate = AVAssetImageGenerator(asset: avAsset)
            assetImgGenerate.appliesPreferredTrackTransform = true
            let time = CMTime(seconds: 0.0, preferredTimescale: 600)
            do {
                let img = try assetImgGenerate.copyCGImage(at: time, actualTime: nil)
                let thumbnail = UIImage(cgImage: img)
                
            } catch {
                //here prints : "The file couldn’t be opened because you don’t have permission to view it."
                print(error.localizedDescription)
            }
        }
        
    }
 } catch  {
    print("exception catch at block - while uploading video")
 }
}

Answer 1

I've been seeing this same error on iOS 14 when simply trying to play a video from iCloud in an AVPlayer . It seems like a bug in the Photos framework and the only "solution" that has worked for me has been to request the highest quality video.

options.deliveryMode =.highQualityFormat

See the comment from @SwiftRabbit on Request AVAsset using iCloud PHAsset returns an AVAsset with no VideoTracks