MPMoviePlayerController: getting a reliable skipped currentPlaybackTime

Question

I play live on the iOS app I am developing. I use MPMoviePlayerController and you need to create custom controls (play, pause, progress bar, etc.).

When I try to get currentPlaybackTime, I notice some very strange behavior: it skips like no tomorrow.

The duration property is stable for 7170 seconds; it never changes. The playableDuration property grows during movie playback, and currentPlaybackTime is constantly jumping:

playableDuration: 7179.875398 currentPlaybackTime: 7170.181204 -------------- playableDuration: 7187.655396 currentPlaybackTime: 7171.079373 -------------- playableDuration: 7197.208128 currentPlaybackTime: 7172.131998 -------------- playableDuration: 7197.208128 currentPlaybackTime: 7173.139118 -------------- playableDuration: 7197.208128 currentPlaybackTime: 7174.139770 -------------- playableDuration: 7197.208128 currentPlaybackTime: 7175.139666 -------------- playableDuration: 7197.208128 currentPlaybackTime: 7176.140805 -------------- playableDuration: 7197.208128 currentPlaybackTime: 7177.139057 -------------- playableDuration: 7197.208128 currentPlaybackTime: 7178.139128 -------------- playableDuration: 7197.208128 currentPlaybackTime: 7179.139911 -------------- playableDuration: 7199.822063 currentPlaybackTime: 7170.095921 -------------- playableDuration: 7209.959997 currentPlaybackTime: 7171.140078 -------------- playableDuration: 7209.959997 currentPlaybackTime: 7172.140715 -------------- playableDuration: 7209.959997 currentPlaybackTime: 7173.076899 -------------- playableDuration: 7209.959997 currentPlaybackTime: 7174.139497 -------------- playableDuration: 7209.959997 currentPlaybackTime: 7175.139907 -------------- playableDuration: 7209.959997 currentPlaybackTime: 7176.138233 -------------- playableDuration: 7209.959997 currentPlaybackTime: 7177.139523 -------------- playableDuration: 7209.959997 currentPlaybackTime: 7178.135736 -------------- playableDuration: 7209.959997 currentPlaybackTime: 7179.138545 -------------- playableDuration: 7209.959997 currentPlaybackTime: 7180.111102 -------------- playableDuration: 7219.939398 currentPlaybackTime: 7171.132859 -------------- playableDuration: 7219.939398 currentPlaybackTime: 7172.128591 -------------- playableDuration: 7219.939398 currentPlaybackTime: 7173.136137 -------------- playableDuration: 7219.939398 currentPlaybackTime: 7174.135416 -------------- playableDuration: 7219.939398 currentPlaybackTime: 7175.137593 -------------- playableDuration: 7219.939398 currentPlaybackTime: 7176.131573 -------------- playableDuration: 7219.939398 currentPlaybackTime: 7177.137812 -------------- playableDuration: 7219.939398 currentPlaybackTime: 7178.131751 -------------- playableDuration: 7219.939398 currentPlaybackTime: 7179.135922 -------------- playableDuration: 7219.939398 currentPlaybackTime: 7180.139828 -------------- playableDuration: 7229.752731 currentPlaybackTime: 7171.129731 -------------- playableDuration: 7229.752731 currentPlaybackTime: 7172.136576 -------------- playableDuration: 7229.752731 currentPlaybackTime: 7173.132362 -------------- playableDuration: 7229.752731 currentPlaybackTime: 7174.139998 

As you can see, it jumps from 7179 to 7170, then from 7180 to 7171 and again and again ... In other words, there seems to be no way to get a stable increment of currentPlaybackTime. This causes my progress bar to move, and the progress bar (0: 04: 30/2: 00: 00) also behaves very strangely.

Has anyone seen this behavior? Is there a workaround?

Answer 1

I finally solved this problem using my own internal property to track playback time:

 @property (nonatomic) NSTimeInterval previousPlaybackTime; @property (nonatomic) NSTimeInterval currentPlaybackTime; @property (strong, nonatomic) NSTimer *timer; - (void)setCurrentPlaybackTime:(NSTimeInterval)currentPlaybackTime { BOOL force = (self.moviePlayer.playbackState == MPMoviePlaybackStatePaused); [self setCurrentPlaybackTime:currentPlaybackTime force:force]; } - (void)setCurrentPlaybackTime:(NSTimeInterval)currentPlaybackTime force:(BOOL)force { if (currentPlaybackTime > self.moviePlayer.duration) { currentPlaybackTime = self.moviePlayer.duration; } if (!force && currentPlaybackTime < _previousPlaybackTime) { // Don't go backwards in time if it less then 50 seconds (solves the 10 seconds going back problem) if (_previousPlaybackTime - currentPlaybackTime < 50) { return; } } if (!force && _previousPlaybackTime && currentPlaybackTime > _previousPlaybackTime) { // Don't go forward in time if it more then 10 seconds (solves the huge jumps when using the progress bar) if (currentPlaybackTime - _previousPlaybackTime > 10) { return; } } _previousPlaybackTime = currentPlaybackTime; _currentPlaybackTime = currentPlaybackTime; } - (void)viewWillAppear:(BOOL)animated { [super viewWillAppear:animated]; self.timer = [NSTimer scheduledTimerWithTimeInterval:1.0 target:self selector:@selector(timedJob) userInfo:nil repeats:YES]; [self.timer fire]; } - (void)timedJob { if (self.moviePlayer.playbackState == MPMoviePlaybackStateSeekingBackward) return; if (self.moviePlayer.playbackState == MPMoviePlaybackStateSeekingForward) return; self.currentPlaybackTime = self.moviePlayer.currentPlaybackTime; } 

So, in my interface I now use self.currentPlaybackTime, which, if I may say so, is built in to protect transitions. When the user uses the slider to change the playback position, you use the force: YES parameter.