Getting artwork for a audio file in Objective-C

gistfile1.m

NSURL *url = [NSURL URLWithString:songFileLocation];
AVURLAsset *asset = [AVURLAsset URLAssetWithURL:url options:nil];

[asset loadValuesAsynchronouslyForKeys:@[ @"commonMetadata" ] completionHandler:^{
	dispatch_async(dispatch_get_main_queue(), ^{
		NSArray *artwork = [AVMetadataItem metadataItemsFromArray:asset.commonMetadata withKey:AVMetadataCommonKeyArtwork keySpace:AVMetadataKeySpaceCommon];
		NSImage *image = nil;
		
		for (AVMetadataItem *item in artwork) {
			if ([item.keySpace isEqualToString:AVMetadataKeySpaceID3]) {
				image = [[NSImage alloc] initWithData:[item.value copyWithZone:nil][@"data"]];
				break;
			} else if ([item.keySpace isEqualToString:AVMetadataKeySpaceiTunes]) {
				image = [[NSImage alloc] initWithData:[item.value copyWithZone:nil]];
				break;
			}
		}
		
		// got NSImage
	});
}];