rumor has it that David wrote:
> andrew strasfogel wrote:
> > I rented a movie DVD and wanted to transfer it to videotape for later
> > veiwing but couldn't because DVDs are now copy protected. So much for "fair
> > use" - they didn't even give me a chance to be honest or fair!
> >
>
> DVDs have two layers of copy protection. The first is a digital
> encryption scheme called CSS.
> The second layer is what prevents you from making a video tape recording
> of a DVD you're playing back. It's called Macrovision. It's an analog
> scheme, also used on rental videocassettes, and in the case of DVDs it's
> actually applied to the outgoing signal by a circuit inside the DVD
> player. I won't go into the technical details here, but it acts by
> interfering with the automatic gain control in the VCR.
This is true. A mostly useless piece of data is that Betamax recorders
are nearly immune to the effect - but they don't strip it. Also, any
VHS deck with a manual video level control (high end pro decks,
usually) will not be too bothered by it.
> At home I have a video projector that simply cannot deal with
> Macrovision; it confuses it into thinking it doesn't have a valid video
> signal. I ended up buying a "video stabilizer" to strip the Macrovision
> encoding off the signal. While I don't use this device for copying, and
> my use of it infringes no one's copyright, I had a hard time getting it
> because the DMCA makes it illegal to sell or even to posess it. It's a
> strange world we live in.
Curious. A device called a TBC (time base corrector), which is an
essential part of any non-hobby tape-based video production system,
will do the same thing. By "rebuilding" the sync portion of the signal
the Macrovision parts are (rightly) tossed out with any other "trash"!
So I am surprised to hear that it's illegal to _posess_ one since there
are so many applications where it's indespensible and legitimate!
But like you said - it's a strange world!!!
Philip, old style video geek
