title: Avmetadataitem Getting the trackNumber from an iTunes or ID3 metadata on iOS
body: <p>I'm trying to get the trackNumber of a aac, mp3 or mp4 file. It's not in the commonMetadata so I started to spelunk in the other metadata keys. I found something that looks like it, but I'm yet unable to read it, and make sense of it. Even the raw data makes no sense to me.</p>
  
  <p>At the moment, I'm just trying to get it using this basic code:</p>
  
  <pre><code>    NSArray *meta = [asset metadataForFormat:AVMetadataFormatiTunesMetadata];
      for ( AVMetadataItem* item in meta ) {
          id key = [item key];
          NSString *value = [item stringValue];
          NSLog(@"key = %@, value = %@", key, value);
      }
  </code></pre>
  
  <p>Knowing I'm looking for AVMetadataiTunesMetadataKeyTrackNumber.</p>