AVURLAsset cannot load with remote file

问题

I have a problem using AVURLAsset.

NSString * const kContentURL = @

"http://devimages.apple.com/iphone/samples/bipbop/bipbopall.m3u8";
...

    NSURL *contentURL = [NSURL URLWithString:kContentURL];
    AVURLAsset *asset = [AVURLAsset URLAssetWithURL:contentURL
                                               options:nil];
    [asset loadValuesAsynchronouslyForKeys:[NSArray arrayWithObject:tracksKey]
                            completionHandler:^{
    ...
                               NSError *error = nil;
                               AVKeyValueStatus status = [asset statusOfValueForKey:tracksKey
                                                                              error:&error];
    ...
    }

In the completion block, the status is AVKeyValueStatusFailed and the error message is "Cannot Open". All exemples I have seen, use a local file, so maybe there is a problem using a remote file...

Regards, Quentin

回答1:

You can't directly create an AVURLAsset for an HTTP Live stream as stated in Apple's AV Foundation Programming Guide. You'll have to create an AVPlayerItem with the stream url and instantiate an AVPlayer with it

AVPlayerItem *pItem = [AVPlayerItem playerItemWithURL:theStreamURL];
AVPlayer *player = [AVPlayer playerWithPlayerItem:pItem];

If you need to have access to the AVURLAsset behind that you could follow these steps.

Step 1/ register for changes of the status property of the player item

[playerItem addObserver:self forKeyPath:@"status" options:0 context:nil];

Step 2/ in observeValueForKeyPath:ofObject:change:context:

- (void)observeValueForKeyPath:(NSString *)keyPath ofObject:(id)object
                        change:(NSDictionary *)change context:(void *)context { 
    if ([keyPath isEqualToString:@"status"]) {
        AVPlayerItem *pItem = (AVPlayerItem *)object;
        if (pItem.status == AVPlayerItemStatusReadyToPlay) {
            // Here you can access to the player item's asset
            // e.g.: self.asset = (AVURLAsset *)pItem.asset;
        }
    }   
}

EDIT: corrected the answer

来源：https://stackoverflow.com/questions/4934886/avurlasset-cannot-load-with-remote-file