But a widespread exemption for cracking the CSS encryption on DVDs has always been a bridge too far. In the first proceedings, the Register of Copyright was convinced by movie industry arguments that users inconvenienced by the ability to stick a copy of a film on their iPhone had other ways to access the material (like VHS tapes). At later hearings, the movie industry argued (and actually demonstrated) how to make copies of movies by pointing a camcorder at a TV screen. Welcome to the technological society!

Another DMCA exemption process is now underway at the Copyright Office, and Public Knowledge has decided to make another run at the DVD issue. The basis of its argument? The prevalence of piracy. Since one can already get digital copies of just about every film off the Internet, there can be little harm in allowing citizens to back up their DVD collections or "space shift" them to computers and smartphones (just as they have long been able to do with compact discs).

"Ultimately, this exemption will have no impact on unauthorized reproductions of motion pictures," the Public Knowledge filing (PDF) concludes. “The Register is in the enviable position of balancing a clear benefit to the public against no cognizable harm to rightsholders because the harm they fear already exists."

The request ignores Blu-ray discs. I asked Public Knowledge why that was. "There are already tools out there for cracking DVDs that are readily accessible, so the Copyright Office would have an easier time with that facet of the issue," said spokesman Art Brodsky.

To justify its request, however, Public Knowledge needs to show real harm to real people from the current system. To that end, the group is going to crowdsource the evidence it will need to make its case.

"So in the next few weeks, we are going to put out a call for you to tell the Copyright Office that this exemption is important," wrote Michael Weinberg on the Public Knowledge blog. "You will need to tell them that you are a real person, who really owns DVDs, who would like to be able to copy the movies you paid for onto other devices you own. We may even ask you to remind the Copyright Office that telling people to use a camcorder to record a movie from a TV screen is a stupid idea."

Should the exception be granted, though, it wo