How does AVPlayer / AVPlayerItem inform my application about unreachable network failure?

Question

I’m using AVPlayer to implement a custom video player in an iOS application. To play video from the network I allocate a player:

[[AVPlayer alloc] initWithURL:_URL];

Create an asset:

AVURLAsset *asset = [AVURLAsset URLAssetWithURL:self.URL
options:@{AVURLAssetPreferPreciseDurationAndTimingKey : @(YES)}];

load the playable key asynchronously:

NSArray *keys = @[@"playable"];
[asset loadValuesAsynchronouslyForKeys:keys completionHandler:^{
    dispatch_async(dispatch_get_main_queue(), ^{
        for (NSString *key in keys) {
            NSError *error;
            AVKeyValueStatus status = [asset statusOfValueForKey:key error:&error];

            if (status == AVKeyValueStatusFailed) {
                NSLog(@"Failed to load asset key %@ error %@", key, [error localizedDescription]);
                [self fail];
                return;
            }
        }

        if (asset.isPlayable) {
            [self.player replaceCurrentItemWithPlayerItem:self.playerItem];
        }
        else {
            [self fail];
        }
    });
}];

The problem is that when the device has no internet connection or high packet loss, the completionHandler is never called (even after waiting for minutes) and so I have no idea when to show a message to the user that loading the video failed.

My questions are:

1. Am I missing something / is there a better way to handle this?
2. Should I roll my own timeout logic or should I just never loadValuesAsynchronouslyForKeys: when Reachability believes that the network isn't reachable.
3. What are the best practices regarding AVPlayer and network failures?

Answer 1

You should be observing (KVO) features of the AVPlayerItem that reveal how the buffer is doing, such as playbackBufferEmpty etc.

Answer 2

I've integrated AVAsset before, but haven't run into this specific issue. Nonetheless, here's what I would do:

1. Set a timer or delayed block dispatch for the length of the timeout you'd like to enforce.
2. Check the value of the "playable" key with statusOfValueForKey:error:.
3. If the status is not AVKeyValueStatusLoaded or error is not nil, call [asset cancelLoading] and display an error message to the user or whatever cleanup you might need to do.