AVPlayer does not update currentPlaybackTime when seeking backwards - ios

I have an NSTimer set up that fires every 0.1 seconds, in the callback I fetch currentTime() and use it to update the label with the duration of the video.
When I am seeking forwards, by setting the rate to 3, this timer keeps up, but when I set the rate to -3, the video keeps up, but the currentTime() still returns the same value from when I started seeking. This occurs until I stop seeking and then currentTime() returns the correct time
How can I fetch the current time the video is at, which will work when seeking backwards?
Edit: Here is the code I use (translated from Xamarin C#):
class VideoPlayer: UIView {
var player: AVPlayer!
var wasPaused: Bool!
func play(url: String) {
// set the URL to the Video Player
let streamingURL: NSURL = NSURL(string: url)!
player = AVPlayer(URL: streamingURL)
let playerLayer = AVPlayerLayer(layer: player)
layer.insertSublayer(playerLayer, atIndex: 0)
// Reset the state
player.seekToTime(CMTime(seconds: 0, preferredTimescale: 600))
// Start a timer to move the scrub label
NSTimer(timeInterval: 0.1, target: self, selector: #selector(playbackTimeUpdated), userInfo: nil, repeats: true)
}
func playbackTimeUpdated() {
// This one is not correct when seeking backwards
let time = player.currentTime().seconds;
// Use the time to adjust a UIProgressView
}
// Gets called when the reverse button is released
func reverseTouchUp() {
player.rate = 1
}
// Gets called when the reverse button is pressed
func reverseTouchDown()
{
player.rate = -3;
}
}

Try CMTimeGetSeconds(player.currentTime()) instead of player.currentTime().seconds. It works for me.
Also check that you timer is actually running (add NSLog calls to it for example), maybe you just blocking its thread.

Related

UISlider jumps when updating for AVPlayer

I try to implement simple player with UISlider to indicate at what time is current audio file.
In code I have added two observers:
slider.rx.value.subscribe(onNext: { value in
let totalTime = Float(CMTimeGetSeconds(self.player.currentItem!.duration))
let seconds = value * totalTime
let time = CMTime(seconds: Double(seconds), preferredTimescale: CMTimeScale(NSEC_PER_SEC))
self.player.seek(to: time)
}).disposed(by: bag)
let interval = CMTime(seconds: 0.1, preferredTimescale: CMTimeScale(NSEC_PER_SEC))
player.addPeriodicTimeObserver(forInterval: interval, queue: nil) { [weak self] time in
self?.updateSlider(with: time)
}
with one private function:
private func updateSlider(with time: CMTime) {
let currentTime = CMTimeGetSeconds(time)
var totalTime = CMTimeGetSeconds(player.currentItem!.duration)
if totalTime.isNaN {
totalTime = 0
}
startLabel.text = Int(currentTime).descriptiveDuration
endLabel.text = Int(totalTime).descriptiveDuration
slider.value = Float(currentTime / totalTime)
}
When audio plays, everything is fine and slider is pretty much updated. The problem occurs when I try to move slider manually while audio is playing, then it jumps. Why?
UPDATE:
I know why actually. Because I update it twice: manually and from player observer, but how to prevent from this behaviour? I have no idea;) please, help.
One simple way to go about this would be to prevent addPeriodicTimeObserver from calling self?.updateSlider(with: time) when the slider is being touched.
This can be determined via the UISliders isTracking property:
isTracking
A Boolean value indicating whether the control is currently tracking
touch events.
While tracking of a touch event is in progress, the control sets the
value of this property to true. When tracking ends or is cancelled for
any reason, it sets this property to false.
Ref: https://developer.apple.com/documentation/uikit/uicontrol/1618210-istracking
This is present in all UIControl elements which you can use in this way:
player.addPeriodicTimeObserver(forInterval: interval, queue: nil) { [weak self] time in
//check if slider is being touched/tracked
guard self?.slider.isTracking == false else { return }
//if slider is not being touched, then update the slider from here
self?.updateSlider(with: time)
}
Generic Example:
#IBOutlet var slider: UISlider!
//...
func startSlider() {
slider.value = 0
slider.maximumValue = 10
Timer.scheduledTimer(withTimeInterval: 0.1, repeats: true) { [weak self] (timer) in
print("Slider at: \(self?.slider.value)")
guard self?.slider.isTracking == false else { return }
self?.updateSlider(to: self!.slider.value + 0.1)
}
}
private func updateSlider(to value: Float) {
slider.value = value
}
I'm sure there are other (better) ways out there but I haven't done much in RxSwift (yet).
I hope this is good enough for now.

Play audio from "paused" point after restarting the track with AVAudioPlayer

I'm working on a music player in Swift. The user can play a track, pause the track, or move a slider to choose a place to start. These three functions work.
However, if a user plays a track, listens for 1:00, and hits pause: when they click play again, it will restart the track from 0:00 instead of respecting where they paused.
I am using AVAudioPlayer as a media player -- according to the documentation, .play() allows you to specify a start-point using atTime.
So I tried to use atTime and have it start where the slider is -- if a listener listens for 1:00, I want atTime to dynamically pick that up. I try to establish this time value in a var.
class MusicViewController: UIViewController {
// removed imports and viewdidload to condense
#IBAction func playDownload(_ sender: Any) {
// removed file download code to condense
do {
audioPlayer = try AVAudioPlayer(contentsOf: destinationUrl)
guard let player = audioPlayer else { return }
//here's where I try to capture a time value from the slider's progress
let checkTime = TimeInterval(Slider.value)
player.prepareToPlay()
player.play(atTime: checkTime)
} catch let error {
print(error.localizedDescription)
}
// updates slider with progress
Slider.value = 0.0
Slider.maximumValue = Float((audioPlayer?.duration)!)
audioPlayer.play()
timer = Timer.scheduledTimer(timeInterval: 0.0001, target: self, selector: #selector(self.updateSlider), userInfo: nil, repeats: true)
}
#IBAction func pause(_ sender: Any) {
if audioPlayer.isPlaying {
audioPlayer.pause()
} else {
audioPlayer.play()
}
}
#IBOutlet var Slider: UISlider!
#objc func updateSlider() {
Slider.value = Float(audioPlayer.currentTime)
print("Changing works")
}
}
So I am trying to capture progress and have .play respect that -- this code will run, but it does not work. No errors but after hitting play, it will go to the end of the track immediately now. No good.
I am new to Swift - any idea where I went wrong?

How to play an audio file sample

Okay I'm trying to do something similar to iTunes not sure if it's still the same. It's when you click a song and it gives a sample of the audio file. This is my code looks.
The music file is like 2-3min long. I got the start time to start at 42sec seconds. However, the song finishes to the end. I'm trying to make the audio file a sample of 30sec. So it should start at 42sec and end at 1min and 12sec.
Would appreciate any help thanks.
Every time your audio sample starts playing, you can create a Timer object which will make your player stop in a given amount of time.
var audioPlayer = AVAudioPlayer()
var timer: Timer?
func prepareMusic() {
....
// Your code to start playing sample
audioPlayer.currentTime = 42
audioPlayer.play()
// Here we are stopping previous timer if there was any, and creating new one for 30 seconds. It will make player stop.
timer?.invalidate()
timer = Timer(fire: Date.init(timeIntervalSinceNow: 30), interval: 0, repeats: false) { (timer) in
if self.audioPlayer.isPlaying {
self.audioPlayer.stop()
}
}
RunLoop.main.add(timer!, forMode: .defaultRunLoopMode)
}
func musicButton(sender: UIButton) {
....
// If sample is stopped by user — stop timer as well
if audioPlayer.isPlaying {
audioPlayer.stop()
timer?.invalidate()
}
}
There is one more edge case I can think of — if you hide/close view controller, you might also want to stop that timer.
override func viewWillDisappear(_ animated: Bool) {
timer?.invalidate()
}

Slider Scrubbing not very smooth

i am trying to implement a slider for AVPlayer to show the length of audio files and allow user to scrub forward and backward.
I've got it working pretty much but when you move the slider knob it reverts back to the original location for a second then skips forward to where you moved it to and starts playing again.
Is there a way to stop this flicking? I'm probably doing something stupid with the code.
This is my block for the slider:
#IBAction func horizontalSliderActioned(_ sender: Any) {
audioPlayer?.pause()
//self.timer?.invalidate()
//create a CMTime the slider value
let seconds : Int64 = Int64(horizontalSlider.value)
let preferredTimeScale : Int32 = 1
let seekTime : CMTime = CMTimeMake(seconds, preferredTimeScale)
audioPlayerItem?.seek(to: seekTime)
audioPlayer?.play()
//self.timer = Timer.scheduledTimer(timeInterval: 0.1, target: self, selector: #selector(PlayerViewController.audioSliderUpdate), userInfo: nil, repeats: true)
}
i am using a timer so i was playing with invalidating and then recreating but it didn't do anything.
This is the timer block:
func audioSliderUpdate() {
let currentTime : CMTime = (self.audioPlayerItem?.currentTime())!
let seconds : Float64 = CMTimeGetSeconds(currentTime)
let time : Float = Float(seconds)
self.horizontalSlider.value = time
}
which is called by the timer, where the audio starts playing:
self.timer = Timer.scheduledTimer(timeInterval: 0.1, target: self, selector: #selector(PlayerViewController.audioSliderUpdate), userInfo: nil, repeats: true)
maximum time is set from duration where the audio is played:
let duration : CMTime = (self.audioPlayer?.currentItem!.asset.duration)!
let seconds : Float64 = CMTimeGetSeconds(duration)
let maxTime : Float = Float(seconds)
self.horizontalSlider.maximumValue = maxTime
I think range of your slider is not set to the range that can be achieved by assigning time to it.
The defaults are set like this:
You need to set them to 0...length of the played sound or enter the time in relative units 0...1, if you didn't already.

animateWithDuration play sound doesn't repeat

I have a pulsing rectangle animated with animateWithDuration and setAnimationRepeatCount().
I'm trying to add a sound effect in the animations block witch is "clicking" synchronously. But the sound effect is only playing once. I can't find any hint on this anywhere.
UIView.animateWithDuration(0.5,
delay: 0,
options: UIViewAnimationOptions.AllowUserInteraction | UIViewAnimationOptions.CurveEaseOut | UIViewAnimationOptions.Repeat,
animations: {
UIView.setAnimationRepeatCount(4)
self.audioPlayer.play()
self.img_MotronomLight.alpha = 0.1
}, completion: nil)
The sound effect should play four times but doesn't.
Audio Implementation:
//global:
var metronomClickSample = NSURL(fileURLWithPath: NSBundle.mainBundle().pathForResource("metronomeClick", ofType: "mp3")!)
var audioPlayer = AVAudioPlayer()
override func viewDidLoad() {
super.viewDidLoad()
audioPlayer = AVAudioPlayer(contentsOfURL: metronomClickSample, error: nil)
audioPlayer.prepareToPlay()
....
}
#IBAction func act_toggleStartTapped(sender: AnyObject) {
....
UIView.animateWithDuration(....
animations: {
UIView.setAnimationRepeatCount(4)
self.audioPlayer.play()
self.img_MotronomLight.alpha = 0.1
}, completion: nil)
}
Providing the UIViewAnimationOptions.Repeat option does NOT cause the animation block to be called repeatedly. The animation is repeated on a CoreAnimation level. If you place a breakpoint in the animation block, you'll notice that it is only executed once.
If you want the animation to execute in a loop alongside the sound, create a repeating NSTimer and call the animation / sound from there. Keep in mind that the timer will retain the target, so don't forget to invalidate the timer to prevent retain cycle.
EDIT: Added implementation below
First, we'll need to create the timer, assuming we have an instance variable called timer. This can be done in viewDidLoad: or init method of a view. Once initialized, we schedule for execution with the run loop, otherwise it will not fire repeatedly.
self.timesFired = 0
self.timer = NSTimer(timeInterval: 0.5, target: self, selector:"timerDidFire:", userInfo: nil, repeats: true)
if let timer = self.timer {
NSRunLoop.mainRunLoop().addTimer(timer, forMode: NSDefaultRunLoopMode)
}
The following is the method fired by the timer every interval (in this case 0.5 seconds). Here, you can run your animations and audio playback. Note that UIViewAnimationOptions.Repeat option has been removed since the timer is now responsible for handling the repeating animation and audio. If you only the timer to fire a specific number of times, you can add an instance variable to keep track of times fired and invalidate the timer if the count is above the threshold.
func timerDidFire(timer: NSTimer) {
/*
* If limited number of repeats is required
* and assuming there's an instance variable
* called `timesFired`
*/
if self.timesFired > 5 {
if let timer = self.timer {
timer.invalidate()
}
self.timer = nil
return
}
++self.timesFired
self.audioPlayer.play()
var options = UIViewAnimationOptions.AllowUserInteraction | UIViewAnimationOptions.CurveEaseOut;
UIView.animateWithDuration(0.5, delay: 0, options: options, animations: {
self.img_MotronomLight.alpha = 0.1
}, completion: nil)
}
Without seeing the implementation of the audio player some things I can think of include:
The audio file is too long and perhaps has silence on the end of it so it is not playing the first part of the file which has the sound in it
the audio file needs to be set to the beginning of the file every time (it could just be playing the end of the file the other 3 times leading to no audio output)
The animation is happening to quickly and the audio doesn't have time to buffer
Hopefully these suggestions help you narrow down the problem but without seeing the implementation of the player, it is really hard to say what the actual problem is.

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