AVPlayer was deallocated while key value observers were still registered with it

Question

I am creating a simple media player app. My App is crashed when first link is played and I clicked second link in uitableview.

- (void)viewDidLoad {
        [s         


        

Answer 1

I had a similar problem. It worked fine in iOS 7, and now it crashes in iOS 8.

The solution was to remove the observer, before releasing the object.

When you replace or allocate a new object for a member, you're releasing the old object, so you need to remove the observer first :

-(void) setupAVPlayerForURL: (NSURL*) url1 {
    AVAsset *asset = [AVURLAsset URLAssetWithURL:url1 options:nil];
    AVPlayerItem *anItem = [AVPlayerItem playerItemWithAsset:asset];
    if (player != nil)
        [player removeObserver:self forKeyPath:@"status"];
    player = [AVPlayer playerWithPlayerItem:anItem]; 
    [player addObserver:self forKeyPath:@"status" options:0 context:nil];
}

And similarly in btnPlayClick ( in case it is pressed without btnStop_Click being pressed) :

- (IBAction)btnPlay_Click:(id)sender {
     if (player != nil && [player currentItem] != nil)
         [[player currentItem] removeObserver:self forKeyPath:@"timedMetadata"];
    AVPlayerItem *item = player.currentItem;
    [item addObserver:self forKeyPath:@"timedMetadata" options:NSKeyValueObservingOptionInitial|     NSKeyValueObservingOptionNew| NSKeyValueObservingOptionOld| NSKeyValueObservingOptionPrior context:nil];
    [player play];
}

Answer 2

I did meet the similar issue when using AVPlayer, the crash log info says:

An instance 0x174034600 of class AVKeyPathFlattener was deallocated while key value observers were still registered with it. Current observation info: ( Context: 0x0, Property: 0x17405d6d0> )

As what Apple recommended, what I originally did is adding observer after initialize my AVPlayerItem object, and remove observer in the observer's dealloc method. Because my observer class kept a strong reference on my AVPlayerItem object, so it should not be deallocated before my observer object was deallocated. I really don't know why this happens.

So I tried solved this problem by using BlocksKit, it works fine for me right now.

Answer 3

When using KVO you must balance calls to addObserver:forKeyPath:options:context: with calls to removeObserver:forKeyPath: (see the KVO programming guide).

Try removing the view controller as an observer when the stop button is tapped e.g.

- (IBAction)btnStop_Click:(id)sender {
    [[player currentItem] removeObserver:self forKeyPath:@"timedMetadata"];
}

Answer 4

-(void)viewWillDisappear:(BOOL)animated
{
[self.player removeObserver:self forKeyPath:@"status" context:nil];
}

Answer 5

It's wise to verify first if the key is being observed or not before removing the observer with a @try @catch, like so:

@try {
    [self.player removeObserver:self forKeyPath:@"status" context:nil];
} @catch (id anException) {
    //do nothing, obviously it wasn't attached because an exception was thrown
    NSLog(@"status key not being observed");
}