Clasic N for VHS

[Ghitulescu]

Has any of you heard of Clasic N copy protection system for VHS? It may be misspelt (classic??), however google couldn't find any reference to any combination of spellings....

It works by employing a variable signal strength (which forces the AGC to kick in) thus the variations in luma. Macrovision doesn't list this method/system.

Not that I need to copy it (I've done it) just out of curiosity.

[setarip_old]

Sounds like the original version of Macrovision. See #1 at:

http://www.mediacollege.com/video/editing/macrovision/

[Ghitulescu]

Thanks, I knew about the macrovision, but I never have had a tape before.
From what I understood, MV works with pulses, in my case the amplitude of the signal is random. The tape was produced around 1995.

[pandy]

Macrovision works in few ways, one of them is variable level of pulses to confuse AGC, maybe difference is in timing of those pulses - Macrovision use sequence flashes and slow level change - on make AGC changing fast second pumping level and make fade effect.
I can imagine that N can use some "random" sequence to avoid Macrovision patents.

[Lyle_JP]

Either way, a Time Base Corrector would fix it, right?

[Ghitulescu]

Either way, a Time Base Corrector would fix it, right?

No, not this one. I had to hook up a signal processor to fix the levels in addition to a TBC.