*giggle*

[lnr]

Paul and I seem to have worked out an ingenious way of getting round copy protection on CDs, or at least to get round the way they implement it by stopping you from playing the CD on your computer.

He'd offered to lend me a copy protected CD you see, so I could test if it would work on my DVD player, before I scrap the CD player. So he popped into the office with a Celine Dion (ick, but it's in the name of science) CD, which is proudly labelled on the front "Will not play on PC/Mac". So I figured what the hell and stuck it in my CD rom drive and hit the play button on the front to see what would happen. It played. But maybe that's just because I'm only playing it in hardware, right? (There's no soundcard on this machine). So he took it back through to his office and tried playing it in software there. It played. So there you go, copy protection (in this case) broken.

Now we just have to find one which *doesn't* just work that I can test. Christi: was it the Mike Oldfield ones you were talking about the other day?

Comments

analog vs digital?

[(Anonymous)]

I think the difference is the way its played, PC cd-roms traditionally played the cd-audio through a seperate analog cable at the back or front (headphone jack) in the same way a non-pc player would. Newer windows (2000 and xp by default) play the cd through the IDE ribbon as digital data and it is converted. These copy-protected cds have deliberate errors on them that when outputted digitally confuse the computer (it tries to use the error-correction but fails). The PC it worked on probably still uses the analog output of the cd-drive for audio.

Sorry for the geekish interruption but it er interested me despite not encountering one of these CDs myself...

Re: analog vs digital?

[ewx.livejournal.com]

That matches my understanding - the aim of the exercise is to prevent CDs being converted to MP3 or OGG, rather than to actually prevent them from playing on a computer at all. The bit I'm less clear on is why the drive can't output the digital audio with the error correction already applied.