Brightness cycling while playing DVDs

July 7, 2005 9:21 AM

Brightness cycling while playing DVDs: My girlfriend has an old Panasonic VCR/TV combo. When I play DVDs on it (using my old Panasonic DVD player), the brightness (luminance) level fluctuates continually, ranging from just brighter than normal to very dark. The kicker: It only happens with some DVDs. What's going on here?

I don't have another DVD player, but running the DVD through my (Mitsubishi) TV doesn't give me the same problem. I haven't been able to find any kind of commonality between the DVDs that do this and the ones that don't -- new, old, one studio vs. another...it seems random. It also happens whether I pipe the signal into the TV via RCA plugs as a video signal (which I normally do), or run it through a modulator and put it on an empty channel (which I do on my old Mitsubishi TV, which only has an RF input.)

Any thoughts?

posted by Vidiot to technology (14 comments total)

Trying to copy VHS tapes "protected" with Macrovision used to do something that looked a lot like what you're describing. Maybe that's what's going on?

If it is a copy-protection scheme, it's possible that it works on some hardware and not elsewhere.
posted by redteam at 9:33 AM on July 7, 2005

My guess (on preview, also) would be Macrovision, which is why you are seeing it on the tv/vcr combo and not a regular tv. You'll get this when you run DVD players through a VCR.
posted by Otis at 9:35 AM on July 7, 2005

This is very likely a Macrovision problem - hooking a DVD player into the input of a VCR causes these exact symptoms. Macrovision is the copy protection scheme built-in to most modern DVD/VCR systems, used to prevent you from making a copy of a DVD. Since your VCR is built into the TV, you're going to have problems.

There are a few solutions: you can buy third-party filters available that help with this particular problem. The other option would be to check you DVD player's model number online and see if there is a way to disable Macrovision. Major name-brand players (such as Panasonic) are less likely to have this ability than smaller named players from China, for example.

For more information, I'd start at Wikipedia.
posted by TommyH at 9:35 AM on July 7, 2005

It's a copy protection scheme. If you run a DVD through something something like a VCR before it hits the TV, it gets messed up in this way, to make it so copies are low-quality. Check wikipedia's article on Macrovision.
posted by CrunchyFrog at 9:35 AM on July 7, 2005

I really need to stop spending so much time previewing my posts for grammar/spelling problems...Nice choice of links, Otis. On preview, nice choice for you as well, CrunchyFrog.
posted by TommyH at 9:37 AM on July 7, 2005

It might also be Macrovision, which you can read about here.
posted by mendel at 9:49 AM on July 7, 2005

We had the same problem when we first tried to plug our DVD played into our archaic TV, via our VCR. We had to get an RF Modulator, about $40 CDN four years ago. Works fine, and saved us buying a new TV.
posted by hamfisted at 9:49 AM on July 7, 2005

When DVDs or VHS tapes have Macrovision normally unused tracks have a wavering/varying "trash signal". This signal causes the VCR to adjust tracking which causes the bright to dark video.
Not all DVD or VHS tapes have Macrovision so sometimes you can watch without a problem.
Grey Boxes were sold in big electronic stores to overcome Macrovision to dub VHS tapes (before DVDs were as available and popular). Since the DMCA was passed you cannot legally buy them.
posted by sailormouth at 9:49 AM on July 7, 2005

DRM sux. (not a new sentiment on my part, but still. I'm just trying to (legally!) watch DVDs through the small TV in the bedroom. And my RF modulator doesn't help.

Well, crap.
posted by Vidiot at 10:12 AM on July 7, 2005

You can erase macrovision guaranteed with a Time Base Corrector. These are 100% legal and generally do NOT advertise their macrovision removing capabilities (in fact, that's just a side effect of how they rewrite the NTSC frames).

If you don't want to spend lots of money, you could try a video stabilizer, but those often only remove macrovision 1, and not the newer DVD-only macrovision 2 (they also violate patents and therefore are illegal/difficult to buy/find). There are boxes that will remove the newer macrovision 2, but rather than cost $20, they'll be $100+.
posted by shepd at 11:14 AM on July 7, 2005

Probably the best solution would just be to buy a cheapo DVD player that has the ability to disable Macrovision. Finding which ones do this is kinda tricky, though. Videohelp might be useful.
posted by neckro23 at 12:10 PM on July 7, 2005

And people wonder why other people are so against DRM and DMCA stuff.

You could also just copy the dvds using a computer, most copying software would strip out any DRM and make them region free aswell.
posted by Iax at 1:07 PM on July 7, 2005

You could try writing to Panasonic. While DRM blows, this is really their fault for making a device that doesn't adhere to the proper automatic gain control behavior. You'll notice that in most VCRs you only see this kick in when you press record.
posted by phearlez at 3:04 PM on July 7, 2005

Yep. Sounds like Macrovision.

Get an RF Modulator, as hamfisted said, if you can't plug your DVD player directly into your tv.
posted by ThePants at 10:16 AM on July 8, 2005