issue with memory warning in swift - uicollectionview

Question

i have save images on png extension and the video on the mp4 in file system when i need to display images i fetch all url from document directory and display it on the collection view its work but i need to display frame of video and images from document directory on the collection view i do it but i get the memory warning i don't know why please any help
the following my code:
// this function for the get video frame and display it on the collection view
func generateThumnail(url : NSURL, fromTime:Float64) -> UIImage {
let asset :AVAsset = AVAsset(url: url as URL)
let assetImgGenerate : AVAssetImageGenerator = AVAssetImageGenerator(asset: asset)
assetImgGenerate.appliesPreferredTrackTransform = true
assetImgGenerate.requestedTimeToleranceAfter = kCMTimeZero;
assetImgGenerate.requestedTimeToleranceBefore = kCMTimeZero;
let time : CMTime = CMTimeMakeWithSeconds(fromTime, 600)
let img:CGImage = try! assetImgGenerate.copyCGImage(at: time, actualTime: nil)
let frameImg : UIImage = UIImage(cgImage: img)
return frameImg
}
// and this is for collection view
func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
return self.arrayOfUrl.count
}
func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "PhotoCell", for: indexPath) as! ShowPhotoAlbumCell
if self.arrayOfUrl[indexPath.row].pathExtension == "mp4" {
let grabTime = 0.50
let img = self.generateThumnail(url: self.arrayOfUrl[indexPath.row] as NSURL, fromTime: Float64(grabTime))
cell.imageViewCell.image = img
cell.imageViewVideo.isHidden = false
}else{
cell.imageViewCell.image = UIImage(contentsOfFile: self.arrayOfUrl[indexPath.row].path)
cell.imageViewVideo.isHidden = true
}
return cell
}
// and this is for array which contain All urls form document directory
override func viewWillAppear(_ animated: Bool) {
super.viewWillAppear(true)
arrayOfUrl = []
if let getImages = WorkingWithFileSystem.fetchAllImagesFromDocumentDirectory(folderName: folderName) {
arrayOfUrl = getImages
}
collectionView.reloadData()
}
please can fix this problem without memory warning
thanks advance

Answer 1

let img = self.generateThumnail(url: self.arrayOfUrl[indexPath.row] as NSURL, fromTime: Float64(grabTime))
cell.imageViewCell.image = img
with
cell.imageViewCell.image = UIImage(named: "thumbnail")!
Sorry , but I think you have to try with some static image for thumbnail and then check.. may be generateThumnail is leaking memory in collection view cellForItemAt method while generating thumbnail image for large sizes video.