IS IT legal to make a copy of that DVD you've just bought so the family can watch it around the home or in the car? In one of the most watched copyright cases in recent years, a judge in northern California ruled last month that copying DVDs for personal use was legal, given the terms of the industry's licence and the way the copies were made.

The wider implication of the ruling remains clouded—not least because the DVD Copy Control Association, the loser in the case, has 60 days to appeal. But whatever the video industry may like to think, the writing is on the wall for copy protection.

Copyright is a tricky thing. It protects only the way that an author, designer, photographer, film-maker or composer has expressed himself. It does not cover the ideas or the factual information conveyed in the work.

What constitutes fair use or an infringement is trickier still. Much depends on the purpose and character of the borrowed material's use. Limited reproduction for the purpose of criticism, comment, news reporting, teaching, scholarship and research is considered fair game. But the wholesale repackaging of the content for commercial use is a flagrant infringement.

In America, the Audio Home Recording Act of 1992 made it legal for people to record copyrighted radio broadcasts for personal use. But while the act said nothing about making digital recordings, ripping copyrighted music tracks off CDs and storing them on an iPod has become an everyday occurrence. Despite the number of iTunes downloaded for a fee, Apple would be in trouble if people were prevented from transferring legitimately owned CDs to their iPods. The software Apple gives away to iPod customers is designed to let them do just that.

Most people think it ludicrous that they can't do the same with the DVDs they own. Now it seems, despite squeals from the movie industry, the law is finally moving in the video fan's favour.

The issue in the recent case was whether Kaleidescape, a maker of digital “jukeboxes” that store a person's video and music collections and distribute the entertainment around the home, had breached the terms of the DVD Content Control Association's CSS (content scrambling system) licence.

A Kaleidescape server stores digital content ripped from CDs and DVDs on its hard drive. The content is then encrypted and fed to various screens and speakers around the home by a secure cable. Kaleidescape claimed that content distributed this way was even safer than it was on the original polycarbonate disks. The judge not only agreed, but couldn't find any breach of the copy-protection licence either.

If the case ends there, to all intents and purposes the notion of fair use would appear to apply to DVDs as well as CDs. The movie industry, which nowadays depends as much on DVD sales as on box-office receipts, still seems to think that making life difficult for its customers is a recipe for success.

After likewise shooting itself in the foot for ages, the record industry is now falling over itself to abandon DRM (digital rights management) on CDs. A number of online music stores such as eMusic, Audio Lunchbox and Anthology have given up using DRM altogether. In a recent survey by Jupiter Research, two out of three music industry executives in Europe reckoned that dropping DRM would improve sales.

The latest music publisher to do so is EMI, which announced in January that it had stopped producing CDs with DRM protection. “The costs of DRM,” it declared, “do not measure up to the results.”

In an open letter entitled “Thoughts on Music”, even Steve Jobs, Apple's charismatic boss and chief evangelist, recently called for the elimination of DRM. From this month, Apple's iTunes will sell EMI's highest quality recordings (those with sampling rates of 256 kilobits per second) without DRM for a small premium.

Belatedly, music executives have come to realise that DRM simply doesn't work. It is supposed to stop unauthorised copying, but no copy-protection system has yet been devised that cannot be easily defeated. All it does is make life difficult for paying customers, while having little or no effect on clandestine copying plants that churn out pirate copies.

Now the copy protection on DVDs is proving just as easy to bypass. The biggest flop has been the CSS technology featured in the recent Kaleidescape case. It was first cracked back in 1999 by a Norwegian programmer called Jon Lech Johansen, who showed, in a few short lines of elegant code called DeCSS, just how trivial such lauded protection systems really were. Since then, even the DRM used to protect the new high-definition video disks (the Blu-ray format from the Sony camp and its HD-DVD rival from the Toshiba alliance) have been cracked wide open.

While most of today's DRM schemes that come embedded on CDs and DVDs are likely to disappear over the next year or two, the need to protect copyrighted music and video will remain. Fortunately, there are better ways of doing this than treating customers as if they were criminals.

One of the most promising is Audible Magic's content protection technology. Google is currently testing this to find the “fingerprints” of miscreants who have posted unauthorised television or movie clips on YouTube.

The beauty of such schemes is that they don't actually prevent anyone from making copies of original content. Their purpose is simply to collect royalties when a breach of copyright has occurred. By being reactive rather than pre-emptive, normal law-abiding consumers are then left in peace to enjoy their music and video collections in any way they choose. Why couldn't we have thought of that in the beginning?