Why is QTMovieLoadStateDidChangeNotification not firing?

Question

I'm seeing that setting up a notification on QTMovieLoadStateDidChangeNotification has no effect and the target selector never gets called. Am I missing something?

In awakeFromNib:

[[NSNotificationCenter defaultCenter] addObserver:self
                                         selector:@selector(movieLoadStateDidChange:)
                                             name:QTMovieLoadStateDidChangeNotification
                                           object:nil];

On loading movie:

NSNumber *num = [NSNumber numberWithBool:YES];
NSDictionary *attributes = [NSDictionary dictionaryWithObjectsAndKeys:
 url, QTMovieURLAttribute,
 nil];

self.mQTMovie1 = [[QTMovie alloc] initWithAttributes:attributes
                                               error:&error];

Also

- (void)movieLoadStateDidChange:(NSNotification *)notification {
NSLog(@"movieLoadStateDidChange got called");
}

Does simply allocating and initializing the movie change its load state? Do you maybe have to pre-roll it, or play it for the state to change? — user1118321, May 03 '13 at 04:47

score 1 · Answer 1 · answered May 03 '13 at 20:33

I'm not sure this is the answer but I've encountered this before. The cause in my case was a file whose codec was supported only by a third-party plugin (Flip4Mac in my case).

The load state notification isn't called until the movie finishes after it auto-plays (to nowhere). For long media files, it effectively looks like the notification is never called, since we rarely wait 5 minutes or an hour for a load notification when testing our code. To the user, it looks like the app simply isn't loading the file.

Having the user disable the plugin's auto-play-on-load in System Preferences resolves the issue but unfortunately this one support FAQ I can't get around since users of the app in question frequently use Flip4Mac to support files from common digital voice recorders.

This is with standard codecs like ProRes and Animation. It was causing issues with setting the movie on a QTMovieLayer since querying the load state was saying it was loaded but it didn't get drawn on screen. In the end I hacked in a 0.2 seconds delay before setting the QTMovieLayer movie and all is good :-) — martinjbaker, May 07 '13 at 13:51

Why is QTMovieLoadStateDidChangeNotification not firing?

1 Answers1