Retrieving movie codec under iOS?

I am trying to find the codec used to compress a movie. I am sure if I need to somehow use CMFormatDescription and get a CMVideoCodecType key. I am stuck as to how to get past the metadata array. Any ideas on how to retrieve the codec?

AVURLAsset* movieAsset = [AVURLAsset URLAssetWithURL:sourceMovieURL options:nil];
NSArray *tracks = [movieAsset tracksWithMediaType:AVMediaTypeVideo];

if ([tracks count] != 0) {
    AVAssetTrack *videoTrack = [tracks objectAtIndex:0];

    //
    // Let's get the movie's meta data
    //

    // Find the codec
    NSArray *metadata = [movieAsset commonMetadata];
 }