The Diving Bell and the Butterfly has all the standard DVD extra features, but in the case of this special movie, the usual stuff is more special. So you've got EPK style featurettes with talking head soundbites and behind the scenes B-roll, but it's worth exploring here.
DVD Review: The Diving Bell and the Butterfly
You get to see how the actors actually worked with the camera, substituting for the star's point of view. You get to see director Julian Schnabel on the set in bathrobes and pajamas. You get to see what lengths they went to in order to capture an aesthetic that is easy to take for granted just getting absorbed in the film.
Schnabel also has a chance to speak with a commentary and Charlie Rose interview. He's much more mellow on the audio track. In the interview, he turns Rose's banal questions into fascinating explanations.
The film holds up well in HD also. It's probably not a big enough title to warrant Blu Ray, but the up conversion works. The actors directly in front of the camera are clear while the backgrounds are out of focus, but the blurry focus shifts according to Jean-Do Bauby's point of view. With cinematography this vital, the fidelity of that reproduction is important.