How can I view the Director's Commentary on Avengers: Age of Ultron?

[iMore Question]

I can't find a way to turn on the director's commentary on my digital copy of Age of Ultron. This is a very important feature to me, and if I can't access it, I'll have to buy the Blu ray, I'm hoping I didn't waste my money.

 

[Bigeric23]

What device are you trying to use?