Film school has its benefits. But if you can't get there, you can still learn an awful lot about filmmaking from those shiny, silver discs that keep appearing in your mailbox or following you home from the video store. Audio commentaries on DVDs give movie fans unprecedented opportunities to sit down and watch a favorite movie with the film's director or star as if they were in your living telling you what went into each shot.

The concept of the running audio commentary was invented for the Criterion Collection of laserdiscs. Their catalog of "classic" titles was aimed at film "connoisseurs," a relatively small niche in the mid-1980s.

Since laserdisc players had the ability to play left and right audio channels separately, and most of the films offered by Criterion were not in stereo, they realized they could retain the film's original soundtrack on one side while adding value to those worn-out, older titles by placing a lecture on the other side. Fans could now choose to watch 1933's King Kong with its normal, mono audio or listen to film historian Ronald Haver talk about how a  certain special effect was achieved as the scene being discussed came on the screen.

The first commentary I heard was on the Criterion laserdisc of The Graduate by UCLA film professor Howard Suber. I was hooked immediately and it has been my benchmark ever since. In the first minute of screen time, Suber explains how every aspect of the film's two opening shots speak volumes about Dustin Hoffman's character as well as the overall theme of the movie, from the use of white in the background, to Hoffman's position within the frame, to the "disembodied voices of God" that guide Benjamin through life.

Most commentaries today are either cobbled together from EPK interview outtakes or recorded off-the-cuff while the commentator watches the movie. Suber really planned and produced his track. He timed where his pauses would be so he could bring up the movie's audio on whatever line he was commenting about. He sometimes uses technical terms like 950mm zoom lens, but even a non-technical listener will be able to understand the context of such comments. Some of the fun observations include the Freudian ramifications of a recurring zebra pattern motif, a description of a humorous voiceover montage that was planned but not used for the scene where Benjamin drives to Berkeley, and a subtle, easy-to-miss shot of Benjamin taking out a condom before his first tryst with Mrs. Robinson. Sorry for the tease, but this excellent audio essay is not available on DVD.

Commentaries have been my film school. They're what make Special Editions special. But they're not all created equal. The great ones enhance future viewings of the movie, while others are a waste of time. Frustratingly, most DVD reviews limit their comments on commentaries to unhelpful generalizations, like "good, but not essential" or "comfortable and informative." I aim to change that. I'll be using this blog to shine a light on some exceptional commentaries that every serious screenwriter and filmmaker should listen to and maybe steer you clear of a few that are nothing more than an extra marketing bullet point on the packaging.

Now it's your turn to comment. Do you listen to commentaries? What are some of your favorites?

Dan Margules is an award-winning filmmaker and the president of San Diego Filmmakers. His short film, Begleiter, is available in a Special Edition from Amazon.com or happy-the-dog.com -- with three audio commentaries!