[mythtv-users] [ G400 ] Hotwo enable flicker filters

Cory Papenfuss papenfuss at juneau.me.vt.edu
Thu Mar 17 22:09:56 UTC 2005

> How do i enable any kind of flicker filter to the matroxfb? Picture quality 
> with mplayer, G400 and the RGB-cable ist fantastic, but any X appication, 
> especially MythTV GUI flickers terribly. Somwhere in the web i've read this 
> would be an issue of human optical perception. Perception of hard edges in 
> GUI's at low frequencies (50Hz) causes the flickering. So many graphic cards 
> support flicker filters to blur the image. From the windows driver i know the 
> matrox g400 does to. But i didn't find anything about flicker filters with 
> the G400 under linux in web. Does sombebody knows how to enable flicker 
> filters?
> I'm using the matrox g400 dual max with the kernel matrox framebuffer, second 
> head connected to tv with the self build VGA to SCART cable.
 	Flicker filtering screws with the picture by definition.  The 
video being played *IS* interlaced, and should be played interlaced. 
Flicker filters are an artifact of trying to reduce perceived flicker from 
computer-generated images, but it's horribly bad for maintaining video 
quality from an interlaced source to interlaced display.

 	All that's really needed is to make a MythTV theme that has this 
in mind.  Once upon a time, X11's 100dpi fonts did this by making sure 
there were no single horizonal lines.  If they were double, the flicker 
wouldn't be noticed as much.  That's the correct solution (short of using 
progressive scan TV)

  	There was some talk awhile back about making such a theme, but I'm 
not sure how far it got.


* Cory Papenfuss                                                        *
* Electrical Engineering candidate Ph.D. graduate student               *
* Virginia Polytechnic Institute and State University                   *

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