How to get video duration in Document Directory

It might be duplicate question but I spent to much time for solution. I download a mp4 file to documentary directory. I can get all file names with this function:

    func listFilesFromDocumentsFolder() -> [String]?
    {
        let fileMngr = FileManager.default;
        let docs = fileMngr.urls(for: .documentDirectory, in: .userDomainMask)[0].path
        return try? fileMngr.contentsOfDirectory(atPath:docs)
    }

And I want to get all of these file's time length. Let me show what I try:

var downs = listFilesFromDocumentsFolder()!
for i in 0...downs.count - 1{
    if(downs[i] == ".DS_Store"){
                continue
    }
    let fileManager = FileManager.default;
    let urls = fileManager.urls(for: .documentDirectory, in: .userDomainMask)
    if let documentDirectory:NSURL = urls.first as! NSURL as! NSURL{ 
         let yourFinalVideoURL = documentDirectory.appendingPathComponent(downs[i])
         let asset : AVURLAsset = AVURLAsset(url: yourFinalVideoURL!) as AVURLAsset
         let totalSeconds = Int(CMTimeGetSeconds(asset.duration))
         let minutes = totalSeconds / 60
         let seconds = totalSeconds % 60
         let mediaTime = String(format:"%02i:%02i",minutes, seconds)
         print( yourFinalVideoURL)
         print(mediaTime)
}

the output is

Optional(file:///Users/utf8/Library/Developer/CoreSimulator/Devices/D4F341F1-38A2-498B-99F0-076BE9164A5C/data/Containers/Data/Application/718927F7-4E39-43A8-B760-2A468F82A10F/Documents/viki50102klr.mp4)
00:00

In my opinion I did wrong when I try to get url of my video file. But how to fix that. I try a lot of things. Even I check if the file is exist or not. Which its exist ofcourse.

Also I try

AVAsset(url: URL.init(url: yourFinalVideoURL)!)

unfortunetely it does not work..

Anyway thank you for solution already...

You shouldn't cast your url to NSURL. Just get your documents directory url, and append your filename and extension to it. Besides that you can get CMTime seconds property which is a double and use String(format:) method to properly display the time in "h m s" format:

let documentDirectory = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask).first!
let videoURL = documentDirectory.appendingPathComponent(downs[i])    
let duration = AVURLAsset(url: videoURL).duration.seconds
    print(duration)
let time: String
if duration > 3600 {
    time = String(format:"%dh %dm %ds",
        Int(duration/3600),
        Int((duration/60).truncatingRemainder(dividingBy: 60)),
        Int(duration.truncatingRemainder(dividingBy: 60)))
} else {
    time = String(format:"%dm %ds",
        Int((duration/60).truncatingRemainder(dividingBy: 60)),
        Int(duration.truncatingRemainder(dividingBy: 60)))
}
print(time)