AVPlayer doesn't show anything

You'd have to do the following:

AVAsset *asset = [AVAsset assetWithURL:[NSURL fileURLWithPath:item.url]];
AVPlayerItem *playerItem = [[AVPlayerItem alloc] initWithAsset:asset];
AVPlayer *avPlayer = [AVPlayer playerWithPlayerItem:playerItem];
AVPlayerLayer *avPlayerLayer = [AVPlayerLayer playerLayerWithPlayer:avPlayer];

avPlayerLayer.frame = self.frame;
[containerView.layer addSublayer:avPlayerLayer];
[self addSubview:containerView];
[avPlayer play];

Hope this helps.

Addendum:

It also depends on your URL; if as you said, you have one such as in this format:

http://www.youtube.com/watch?v=zPP6lXaL7KA&feature=youtube_gdata_player

Then you should use this instead:

[NSURL urlWithString:item.url]; 

Given that item is your object and url is a property there of object type NSString.