It could now be illegal to make a compilation of your favourite tunes under new copyright laws - and soon even tougher measures could be introduced.
Dot.life - Where tech and life collide, every Monday
By Mark Ward
BBC News Online technology correspondent
What we can do with the CDs, DVDs and videos lining our shelves has changed this month - the law now takes a dim view of anyone who copies, or attempts to change.
A mix disk for the car may be illegal
For this month, the European copyright directive has come into force in the UK. This puts in place legal protection for companies that try to protect copyrighted products with what is known as a digital rights management (DRM) system - examples include putting errors in music CDs so computer drives can't play them, or locking software until the customer registers online to prove they have permission to use it.
The UK's version of the directive is called the Copyright and Related Rights Regulations 2003, and it is being implemented 10 months late. Controversy over the scope of the directive has delayed its implementation in many other European nations, and nine member states have yet to introduce their own versions.
While much of what home users do with their CDs, DVDs and videos could now be legally questionable, the directive is instead aimed at large-scale piracy outfits, says Francisco Mingorance, the director of public policy at the Business Software Alliance, which co-ordinates anti-piracy work at many hi-tech firms.
The zeal of these counterfeiters means that up to one in three CDs sold is a pirate copy, according to a report by the International Federation of the Phonographic Industry.
Mr Mingorance says the directive gave long awaited legal protection to the devices BSA members use to guard against piracy. This means that many music and movie makers are more likely to make their wares available online as locking devices now have legal protection.
Is that the genuine article? One-third of CDs sold are pirate copies
But others are not so sure the directive is a positive step. Julian Midgley, the head of the Campaign for Digital Rights, says in some respects nothing has changed.
"It makes no difference to the basics - copyright infringement is still copyright infringement and you are as liable as you were before."
But, says Mr Midgley, the important point about the directive is that it establishes in the minds of copyright owners that DRM systems work, albeit not in the way the EU intended.
In the US, the laws put in place to protect DRM systems are being used as competitive tools. Some firms have put trivial locking devices into their software to stop reverse engineering of their products, says Mr Midgley.
The new copyright laws also mean that many of the things we are used to doing, such as playing a music CD on a computer drive or copying tracks to an MP3 player, now fall into a legal grey area.
Before the directive was passed, circumventing the copy-protection device - which could be as simple a matter as putting a black pen mark around the edge of the disk - was tolerated. But now that is a breach of the law, even though you otherwise have the right to listen to that CD.
File-sharing is under legal scrutiny
Some have pointed out that fast-forwarding through the ads at the start of a DVD now contravenes the law. And using a file-sharing service is an infringement, although one that, as yet, is likely to go unpunished.
But maybe not for long. The EU is building these copyright laws into another, the European Intellectual Property Enforcement Directive, which will give even more powers to copyright owners to protect their creations. This will criminalise all efforts to break copyright, even trivial ones.
And that could mean you, with that compilation of your favourite tracks.