Get the accurate duration of a video

if let url = Bundle.main.url(forResource: "small", withExtension: "mp4") {
        let asset = AVAsset(url: url)

        let duration = asset.duration
        let durationTime = CMTimeGetSeconds(duration)
        let minutes = durationTime/60
        let seconds = durationTime%60
        let videoDuration = "\(minutes):\(seconds)"
        print(videoDuration)
    }

This works for me:

import AVFoundation
import CoreMedia

...

    if let url = Bundle.main.url(forResource: "small", withExtension: "mp4") {
        let asset = AVAsset(url: url)

        let duration = asset.duration
        let durationTime = CMTimeGetSeconds(duration)

        print(durationTime)
    }

For the video here it prints "5.568" which is correct.

Edit from comments:

A video that returns 707 seconds when divided by 60 sec/min is 11.78. This is 11.78 minutes, or 11 minutes and 0.78min * 60sec/min = 47sec, total is 11 min 47 sec