The rest is commentary

Tonight I listened to the audio commentary on "This is Spinal Tap." Harry Shearer, Michael McKean and Christopher Guest participate in character as the three band members in director Rob Reiner's mock documentary. I don't think I'd seen the film since it came out in 1984, but I'd heard that the commentary track was pretty funny, and it is.

Personally, I'm one of those people who loves nothing better than to listen to the commentary after watching a great movie on DVD. I've even gone so far as to tape the audio and upload it to my iPod for listening on the go.

Unfortunately, it's difficult to know which ones are worthwhile. Sometimes they're full of technical jargon. Other times, they're not specific enough or contain too much dead air, long stretches when no one is talking. Sometimes they simply become an excuse for the actors and director to lavish each other with praise, or for the director to point out which friends and family members got bit parts in the movie.

I think the best ones don't simply describe what's going on in a particular scene, but really enhance my appreciation of the movie by pointing out things that I might have missed. They include plenty of behind-the-scenes stories, background about how the movie came to be made, some historical perspective if it's based on a true story, and a sense of what the actors and director were trying to achieve.

Some of the best commentaries I've listened to are Francis Ford Coppola (pictured above) on all three parts of "The Godfather," Roger Ebert on "Citizen Kane" and "Casablanca," and screenwriter Julian Fellowes on the Robert Altman movie "Gosford Park." Morgan Freeman and Matthew Broderick provide some very interesting, poignant remarks on the making of the Civil War movie "Glory," and as bonus, you can see them talking in a small pop up in a corner of the screen. Also, as a Kevin Spacey fan, in addition to his singing and dancing, I really enjoyed his commentary on the Bobby Darin biopic "Beyond the Sea."

Fellowes, who won an Oscar for his work on the movie, is a great example of someone who goes beyond describing what I'm seeing on the screen. He obviously knows the social environment of the movie intimately, as he talks in great depth about the upstairs/downstairs world of an English country house in the 1930s.

And Ebert, in a witty, conversational style recounts all of the stories behind the making of those two classic films. I especially love his commentary on "Casablanca," my favorite movie of all time. (There was never any doubt that Ilsa was getting on that plane with Victor Lazlo. This was 1942 and he was her husband).

Coppola's commentaries are probably the best I've ever heard, and I've listened to all nine hours. At times sounding frustrated and angry, he recounts in detail the process of adapting Mario Puzo's novel, his struggles with the studio, the casting process, and how he created a distinct cinematic style in scenes such as the wedding that opens the first Godfather movie.

Some filmmakers, such as Steven Spielberg and Woody Allen, are notorious for not doing commentaries. At least Spielberg offers substantial making-of documentaries for classics such as "Jaws," many of them by Laurent Bouzereau. Woody offers his fans bupkus. Oh what I wouldn't give for Woody and Diane Keaton to record a commentary for "Annie Hall," another one of my all-time favorite movies.

Here's a site that gives brief descriptions of the best tracks on both recent and classic films, and another one that ranks the Top 100 commentaries according to user votes. For tips on what to avoid, you can also check out a list of the lowest-rated commentaries. And DVD Movie Guide provides an in-depth review of extras on the new releases that it reviews.