Video preload in uicollectionview in swift - ios

Question

I am developing Instagram-like an app that has insta reels-like UI where videos are played in the list but what happens now is when cell comes on scree video buffers or loads and it takes 1-2 sec to load because of that uicollectionview scroll lags.
func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
let currentItem = appData[indexPath.item]
let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "swipablePostCollectionViewCell", for: indexPath) as! swipablePostCollectionViewCell
preFetchNextItems(currentIndexPath: indexPath)
if currentItem["video_url"] != "" && currentItem["video_url"] != nil {
cell.postVideoView.isHidden = false
cell.postImageView.isHidden = true
cell.postVideoView.tag = indexPath.item
DispatchQueue.main.async {
if let imageURL: URL = URL(string: currentItem["video_url"]!) {
if indexPath.item == 0 {
let item = VersaPlayerItem(url: imageURL)
cell.postVideoView.set(item: item)
cell.postVideoView.play()
} else {
if let newItem = self.prefetchedData[indexPath.item - 1] as? VersaPlayerItem {
cell.postVideoView.set(item: newItem)
}
}
cell.postVideoView.controls?.behaviour.shouldHideControls = false
cell.postVideoView.isPipModeEnabled = false
cell.postVideoView.autoplay = false
cell.postVideoView.renderingView.playerLayer.videoGravity = AVLayerVideoGravity.resizeAspect
cell.postVideoView.layer.backgroundColor = UIColor.black.cgColor
cell.postVideoView.use(controls: cell.controls)
cell.postVideoView.playbackDelegate?.startBuffering(player: cell.postVideoView.player)
cell.tag = indexPath.item
}
}
return cell
} else {
cell.postVideoView.isHidden = true
cell.postImageView.isHidden = false
if let imageURL: URL = URL(string: currentItem["image_url"] ?? "") {
cell.postImageView.sd_setImage(with: imageURL, placeholderImage: UIImage(named: "error"), options: .delayPlaceholder, context: nil)
cell.postImageView.contentMode = .scaleAspectFill
cell.postImageView.clipsToBounds = true
}
return cell
}
}
And for prefetch
func preFetchNextItems(currentIndexPath: IndexPath?) {
if currentIndexPath?.item == 0 {
for i in 1...4 {
let indexP = IndexPath(item: i, section: 0)
arrFetchedIndexPaths.append(indexP)
lastFetchedIndexPath = indexP
GetDataForPrefetchIndexPath()
}
} else {
let newIndePath = IndexPath(item: lastFetchedIndexPath!.item + 1, section: lastFetchedIndexPath!.section)
arrFetchedIndexPaths.append(newIndePath)
lastFetchedIndexPath = newIndePath
GetDataForPrefetchIndexPath()
}
print("Prefetch indexpath - ", arrFetchedIndexPaths)
}
func GetDataForPrefetchIndexPath() {
if appData.count > lastFetchedIndexPath!.item {
let currentItem = appData[lastFetchedIndexPath!.item]
if currentItem["video_url"] != "" && currentItem["video_url"] != nil {
if let imageURL: URL = URL(string: currentItem["video_url"]!) {
let newItem = VersaPlayerItem(url: imageURL)
prefetchedData.append(newItem)
}
} else {
if let imageURL: URL = URL(string: currentItem["image_url"] ?? "") {
// let newImage = sd_setImage(with: imageURL, placeholderImage: UIImage(named: "error"), options: .delayPlaceholder, context: nil)
prefetchedData.append(imageURL)
}
}
for item in prefetchedData {
print(item)
}
}
}
What i need is on first cell next 4 cell video should preloaded and after user scrolls next cell video should load
so that when user scrolls to next cell video will be preloaded and played without buffer.