I resolved it using Photos framework. PHAssetChangeRequest has a property isFavorite. You can set true as mentioned in below code: -
Swift 3:
PHPhotoLibrary.shared().performChanges({
let request = PHAssetChangeRequest.creationRequestForAssetFromVideo(atFileURL: self.videoWatermarkedURL!)
request?.isFavorite = true
}) { saved, error in
if saved {
OperationQueue.main.addOperation({
UIAlertController.sharedInstance().showAlert(withTitle: AMTSavezees, message: "Video Saved in Favorite!", autoHideDuration: 3)
})
}
}
Good luck.