AVAudioRecorder and AVAudioPlayer audio have different length - swift

Question

I record with AVAudioRecorder, then pause it, print the currentTime, stop it and close it.
When I play the audio and print the duration of it, it is always different than the currentTime.
How is that possible? I don't do anything with the audio after pausing it besides saving it so how is there a different length?
recorder.pause()
print(recorder.currentTime) //e.g. 1.14
recorder.stop()
print(Manager.getAudioFileLength(url)) //e.g. 1.31
do {
try player = AVAudioPlayer(contentsOfURL: url)
}
catch let error as NSError {
NSLog("error: \(error)")
}
print(player.duration) //e.g. 1.25
And in Manager
class Manager {
static func getAudioFileLength(url : NSURL) -> Float64 {
let audioAsset = AVURLAsset(URL: url)
let audioDuration = audioAsset.duration
let audioDurationSeconds = CMTimeGetSeconds(audioDuration)
return audioDurationSeconds
}
}

Answer 1

From the Apple Documentation of AVAsset (superclass of AVURLAsset):
If providesPreciseDurationAndTiming is false, a best-available estimate of the duration is returned. ... If providesPreciseDurationAndTiming is true the absolute precision, at whatever processing cost that entails–and cost can be significant for certain media formats, such as .mpg.