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Discussion Starter · #1 ·
Could someone elaborate on what effect - if any - macrovision has on projectors (and scalers for that matter). Since I don't have anything that outputs macrovision I really don't know - but the question came up in a different situation and thought it would be useful to illuminate the subject further.


I may upgrade to a different DVD player in the future (and may not be able to get that modded) and so this would be more important to me some day.


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/frode


[This message has been edited by Frode (edited 10-12-2001).]
 

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Well, there are two levels of Macrovision. The original Macrovision adds white boxes in the vertical blank area that ramp up and down in brightness to mess with the automatic gain controllers in recording devices, hopefully making any recording come out too annoying to use.


The white boxes don't seem to affect very many projectors when the video is interlaced, because that form of Macrovision has been around for years and projector manufacturers developed ways of dealing with it. But DVD players are required to apply Macrovision to progressive signals as well (even though no consumer devices can record progressive signals). Macrovision on progressive video was generally not anticipated by projector manufacturers, so on some pre-2000 projectors like my NEC LT100, a 480p signal with Macrovision causes the picture to warp at the top like this:

http://dp70.dyndns.org/tmp/mv-1.jpg


My understanding is that more modern projectors don't have a problem with 480p+Macrovision. Firmware updates are available to correct the problem on some NEC projectors (such as the VT540).


In my testing, I found that not all Macrovision implementations cause the above problem. On my LT100, I tried 480p from Sony 9000ES, Pioneer DV-37, and Toshiba 6200 DVD players. All three have Macrovision on their progressive outputs, but the 6200 did not exhibit the warping problem for some reason.


So for these Macrovision issues, it's probably a good idea to check compatibility on your own or search the forums to see if anyone else seems to be successfully using a particular combination of equipment.


A scaler or line doubler will tend to effectively strip off the Macrovision by processing only the active image area of the source video. And of course, the output stage in a scaler will not add new Macrovision. Thus, a scaler can tend to remove Macrovision, as long as its input stage isn't itself sensitive to Macrovision.


Newer implementations of Macrovision have a technology called "colorstripe". Supposedly this alters the colors in the video image area in a high frequency pattern, such that if you record the signal to a device with limited bandwidth (i.e. a VCR), the aliasing from resolution loss results in nasty color bands appearing, again with the intent of making the recording too annoying to use.


Macrovision colorstripe generally doesn't affect projectors since nobody is using projectors with less video bandwidth than the source (well maybe really crappy old 320x240 LCD projectors like the Sony CPJ-100 would be affected?). However, it may bother some people to know colorstripe is there (in most DVD players sold today) polluting the image, even if it is not always visible...



[This message has been edited by Mark Fontana (edited 10-12-2001).]
 

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Discussion Starter · #3 ·
Thanks for the picture - very illustrative (ewww). Any idea if Macrovision has any effect on 3:2 pulldown detection and general de-interlacing?


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/frode
 

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Mark,


Are you in the industry? This is a considerably handy post, and something I've been meaning to look into for some time.


Privately, if you prefer, tell me your background and such.


Frode, Macrovision should not affect those things at all.


Thanks,

John Gannon

[email protected]

(800) 272-4411 mobile
 

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I'm actually not in the industry; I just read up on things and experiment with hardware like many other folks on AVS. But my employment does involve embedded systems and reverse engineering, so I probably tend to dig into this stuff a little more deeply than some people...
 
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