def duration
      return nil unless valid?
      
      units = raw_duration.split(":")
      (units[0].to_i * 60 * 60 * 1000) + (units[1].to_i * 60 * 1000) + (units[2].to_f * 1000).to_i
    end
def duration
      return nil unless valid?
      
      units = raw_duration.split(":")
      (units[0].to_i * 60 * 60 * 1000) + (units[1].to_i * 60 * 1000) + (units[2].to_f * 1000).to_i
    end
The duration of the movie in milliseconds, as an integer.

 Example:

   24400         # 24.4 seconds

 Note that the precision of the duration is in tenths of a second, not
 thousandths, but milliseconds are a more standard unit of time than
 deciseconds.