avplayeritem always at unknown status

Question

I just found a very strange problem,

when loading a mp3 file from local storage,

avplayeritem always at unknown status and can not been played if the file placed in document folder.

way 1:

//AVAsset *asset = [[AVURLAsset alloc] initWithURL:_URL options:nil];
//AVPlayerItem *playerItem = [[AVPlayerItem alloc] initWithAsset:asset];

AVPlayerItem *playerItem = [[AVPlayerItem alloc] initWithURL:_URL];
//line 1
while (playerItem.status!=AVPlayerItemStatusReadyToPlay
       && playerItem.status!=AVPlayerItemStatusFailed) {
    NSLog(@"avplayer: %@ status: %d", playerItem, playerItem.status);
    [[NSRunLoop currentRunLoop] runMode:NSDefaultRunLoopMode beforeDate:[NSDate distantFuture]];
} 
//line 2

NSLog(@"avplayer status: %d item: %@", playerItem.status, _URL);
NSArray *metadata = [playerItem.asset commonMetadata];

way 2:

AVAsset *asset = [[AVURLAsset alloc] initWithURL:_URL options:nil];
AVPlayerItem *playerItem = [[AVPlayerItem alloc] initWithAsset:asset];
/*
AVPlayerItem *playerItem = [[AVPlayerItem alloc] initWithURL:_URL];
//line 1
while (playerItem.status!=AVPlayerItemStatusReadyToPlay
       && playerItem.status!=AVPlayerItemStatusFailed) {
    NSLog(@"avplayer: %@ status: %d", playerItem, playerItem.status);
    [[NSRunLoop currentRunLoop] runMode:NSDefaultRunLoopMode beforeDate:[NSDate distantFuture]];
} 
//line 2
 */
NSLog(@"avplayer status: %d item: %@", playerItem.status, _URL);
NSArray *metadata = [playerItem.asset commonMetadata];

the ouput:

2015-03-19 00:42:49.243 goodnightfm[6737:353911] avplayer: <AVPlayerItem: 0x7fdc3bbd5c00, asset = <AVURLAsset: 0x7fdc3bbd8a50, URL = file:///Users/galenzhao/Library/Developer/CoreSimulator/Devices/123A77A7-DC61-4795-8D9A-E71002E261DA/data/Containers/Data/Application/4CCEED79-1D5A-4D00-BC5E-FC52BD5393F9/Documents/CMStorage/70efdf2ec9b086079795c442636b55fb>> status: 0

but way2 code works well if the mp3 file was in app bundle even the status still suck in unknown ,

2015-03-19 00:45:35.977 goodnightfm[6783:355678] avplayer status: 0 item: file:///Users/galenzhao/Library/Developer/CoreSimulator/Devices/123A77A7-DC61-4795-8D9A-E71002E261DA/data/Containers/Bundle/Application/F2446C29-49F3-4B92-A7B0-7EFCC1A19274/goodnightfm.app/demo5.mp3

I'm sure that the file in app bundle &document are same one, it can be playing in any other software,

by using way2 ,the only different between bundle file &document file was,

if the mp3 file placed in bundle, this function can return metadata

NSArray *metadata = [playerItem.asset commonMetadata];

but return nil by using document url

Hindermost

You should wait for the status to change by observing the status key path using KVO. – Kurtis

Answer 1

First you need to add an observer to the player item to check its status appropriately:

[playerItem addObserver:self 
             forKeyPath:@"status"
                options:NSKeyValueObservingOptionInitial | NSKeyValueObservingOptionNew
                context:nil];

Or add an observer to an AVPlayer object:

[player addObserver:self 
         forKeyPath:@"currentItem.status"
            options:NSKeyValueObservingOptionInitial | NSKeyValueObservingOptionNew
            context:nil];

Then add an observer method like this:

- (void)observeValueForKeyPath:(NSString *)keyPath
                      ofObject:(id)object
                        change:(NSDictionary *)change
                       context:(void *)context {
    if ([object isKindOfClass:[AVPlayerItem class]] && [keyPath isEqualToString:@"status"]) {
        AVPlayerItem *playerItem = (AVPlayerItem *)object;
        NSLog(@"avplayer: %@ status: %d", playerItem, playerItem.status);
    }
    else if ([object isKindOfClass:[AVPlayer class]] && [keyPath isEqualToString:@"currentItem.status"]) {
        AVPlayer *player = (AVPlayer *)object;
        NSLog(@"avplayer: %@ status: %d", player.currentItem, player.currentItem.status);
    }
}

If you still do not get the player item ready, please make sure the audio file really exists at the document directory path specified by the URL.

Alberthaalberti

What is the point of adding both, player and playerItem as observers; shouldn't playerItem be sufficient? – Suppliant

One does not need to register observers to get readyToPlay. Didn't downvote, because the very last sentence actually solved this issue in my project: it is an audio recorder app, and I didn't stop AVAudioRecorder before I used its url property. – Saddle

@Saddle You are correct, you solved my issue on iPad. – Joeljoela

I just had an issue where the status never changed from .unknown even though the video actually played. I was observing for status changes on the AVPlayerItem. When I changed to observing for \.currentItem?.status on the AVQueuePlayer instead, it worked perfectly! – Haslet