Converting CMTime To String is wrong value return

Question

I want CMTime to String an human readable.
So I Found below code.

extension CMTime {

    var durationText:String {
        let totalSeconds = CMTimeGetSeconds(self)
        let hours:Int = Int(totalSeconds / 3600)
        let minutes:Int = Int(totalSeconds.truncatingRemainder(dividingBy: 3600) / 60)
        let seconds:Int = Int(totalSeconds.truncatingRemainder(dividingBy: 60))

        if hours > 0 {
            return String(format: "%i:%02i:%02i", hours, minutes, seconds)
        } else {
            return String(format: "%02i:%02i", minutes, seconds)
        }
    }

}

And I Have 30 second video files. It's CMTime value is 17945.
I expect this durationText 00:30.
But result is 00:29.
And other video files same.
What Should I fix??

Hedley

Your durationText extension returns 00:30 for me. when I run CMTime(value: 30, timescale: 1).durationText – Stilliform

https://mcmap.net/q/975179/-swift-datecomponentsformatter-drop-leading-zeroes-but-keep-at-least-one-digit-in-minutes-place – Stilliform

Just some notes. You can use CMTime instance property seconds. No need to create a variable for that. let hours = Int(seconds / 3600). Btw Swift is a type inferred language. No need to explicitly set the type to Int. – Stilliform

extension CMTime { var hrs: Int { return Int(seconds / 3600) } var mins: Int { return Int(seconds.truncatingRemainder(dividingBy: 3600) / 60) } var secs: Int { return Int(seconds.truncatingRemainder(dividingBy: 60)) } var duration: String { return hrs > 0 ? String(format: "%i:%02i:%02i", hrs, mins, secs) : String(format: "%02i:%02i", mins, secs) } } CMTime(value: 30, timescale: 1).duration ` – Stilliform

@LeoDabus I tried CMTime value is 17945. and timescale is 600 – Hedley

Why don't you work with timescale 1? – Stilliform

the result is correct 18000 should return 30 – Stilliform

I do not init CMTime. It's just my video file's duration. – Hedley

https://mcmap.net/q/1781448/-how-to-get-video-duration-fro-avasset-in-swift – Stilliform

@LeoDabus I tried your past answer. but It's just print out 0m 29s – Hedley

You video duration is less than 30s. the duration is 29.90833333333333 what would you expect? Round up the result yourself if you need it. seconds.rounded(.up) – Stilliform

@LeoDabus No...In Xcode, this video file's duration is 30s. and Finder QuickTime Player also 30s. But why In my app 29s??? – Hedley

@LeoDabus Ah...Okay I See. I understand – Hedley

probably better to use the standard rounded() which uses .toNearestOrAwayFromZero rounding rule. – Stilliform

@LeoDabus So much thankyou. I fixed it. You just answer anything. I select your answer. – Hedley

Answer 1

You need to round your seconds before calculating your time components.

extension CMTime {
    var roundedSeconds: TimeInterval {
        return seconds.rounded()
    }
    var hours:  Int { return Int(roundedSeconds / 3600) }
    var minute: Int { return Int(roundedSeconds.truncatingRemainder(dividingBy: 3600) / 60) }
    var second: Int { return Int(roundedSeconds.truncatingRemainder(dividingBy: 60)) }
    var positionalTime: String {
        return hours > 0 ?
            String(format: "%d:%02d:%02d",
                   hours, minute, second) :
            String(format: "%02d:%02d",
                   minute, second)
    }
}

---

Testing all the possible edge rounding cases:

CMTime(value: 0, timescale: 600).positionalTime              // "00:00"
CMTime(value: 300, timescale: 600).positionalTime            // "00:01"
CMTime(value: 600, timescale: 600).positionalTime            // "00:01"

CMTime(value: 18000 - 600, timescale: 600).positionalTime      // "00:29"
CMTime(value: 17945, timescale: 600).positionalTime            // "00:30"
CMTime(value: 18000, timescale: 600).positionalTime            // "00:30"
CMTime(value: 18055, timescale: 600).positionalTime            // "00:30"
CMTime(value: 18000 + 600, timescale: 600).positionalTime      // "00:31"


CMTime(value: 2160000 - 600, timescale: 600).positionalTime  // "59:59"
CMTime(value: 2160000 - 300, timescale: 600).positionalTime  // "1:00:00"
CMTime(value: 2160000, timescale: 600).positionalTime        // "1:00:00"

Stilliform