MPMoviePlayerController blocking the Main Thread

Question

I am using the MPMoviePlayerController(MPMPC) to stream audio into an application and thats working really fine. Just with one exception, during low network connectivity the app becomes unresponsive.

Now I have even tried to use AVPlayer too but with more or less same experience. And for some reason I cannot find any issues related to this on the internet. So I am not sure if this is from my end or is it how MPMoviePlayerController behaves during low connectivity.

I even tried to log any function that is being called after giving URL to the MPMPC but none of the functions are called.

I have used below three notification to get events of the MPMPC

MPMoviePlayerLoadStateDidChangeNotification
MPMoviePlayerPlaybackDidFinishNotification
MPMoviePlayerPlaybackStateDidChangeNotification

Answer 1

Once the available networking bandwidth is becoming too low to keep up proper playback, MPMoviePlayerController will trigger the MPMoviePlayerLoadStateDidChangeNotification and the loadState will have MPMovieLoadStateStalled set.

You may then mask the load-state within your notification handler and run any actions needed by your app for this state:

if ((movieController_.loadState & MPMovieLoadStateStalled) == MPMovieLoadStateStalled)
{
   NSLog(@"playback stalled - make sure we don't block now!");
}

Once the player has recovered, once again the MPMoviePlayerLoadStateDidChangeNotification is triggered and the loadState property will have the bits for MPMovieLoadStatePlaythroughOK set:

if ((movieController_.loadState & MPMovieLoadStatePlaythroughOK) == MPMovieLoadStatePlaythroughOK)
{
   NSLog(@"playback should run uninterrupted from now on.");
}

However, I never experienced any interface slowdowns of my app caused by the MPMovieLoadStateStalled state. I'ld say that must be your code acting weird, it is not MPMoviePlayerController as I know it. Additionally, those notifications are always sent, I never experienced scenarios in which they were not properly triggered.

I can only recommend to recreate this issue within a minimal test-case and work your way up from that one towards your app (possibly from both sides, test-case and your app).

For simulating bandwidth breakdowns, I would recommend using Charles proxy.