AW: [mythtv-users] Hardware for Best TV-Out?

Cory Papenfuss papenfuss at juneau.me.vt.edu
Mon Oct 25 21:45:49 UTC 2004


> Iīm currently using a gf4mx with a selfmade vga2rgb converter
> (http://www.nexusuk.org/projects/vga2scart/) which is giving me uber-superb
> quality on the frontend and good quality @watching recordings. Iīm still
> investigating the cause for the notīso sharpenes off my recordings/livetv.

 	I "discovered" that when I got my equivalent NTSC circuit built. 
I built up some test patters and convinced myself that the PVR-250 itself 
was limiting the capture resolution to about 520x480 maximum.  Anything 
over that produced no better resolution on even a static image.  I know it 
wasn't the TVOUT because of trying the test patterns directly (720x480 and 
1440x480).  Here's the beta-quality DVD image I came up with at the time:
http://www.ee.vt.edu/~mythtv/
 	Be warned though, I've never actually tried the PAL stuff on 
anything... just changed the resolution of some pictures and re-authored 
the images.

> It seems to me that there ainīt no interlaced output if I watch
> tv/recordings, although I donīt get as heavy stuttering on the cnnticker as
> I had on svideo out of the card. Iīll try to throw some official
> testpatterns on it via mpeg and mythgallery maybe I can then clearly
> describe the problem.

 	I ended up adding deinterlacing to my recordings because I would 
get some strange beat frequency/vsync-related tearing without it.  I'm 
currently using KernelDeint and have been quite satisfied.  Bob deint is a 
bit much for the PIII-800 hardware.
>
> Maybe anyone can help me here as I clearly have interlaced output on the
> frontend. Whats the difference between frontend output and watchingtv -
> output? It even seems to look better in the video epg. XV, OpenGL vsync
> should I try to compile without one/both of these (I think I wonßt get any
> reasonable output on my p3-700 without xv)?
> I have no deinterlace or any other filters activated, playback is full pal
> resolution 720x576 my x resolution that’s put on my tv is 768x576 (shouldīt
> that be right due to square/non square pixel issues?). So can anyone
> describe me the difference between frontend and movie-watching please?
> Thanks
> Flo

 	It depends on what you mean by "better."  If you are talking about 
vertical tearing on recordings, I solved that with the deint.  The 
softness of the capture I traced to the PVR-250 itself.  If it's any 
consolation, the three BTTV-based cards I've tried have all crapped out at 
about 400x480, max.  Anything over that takes space but doesn't help 
pictures quality.

Hope that helps... see if you can quantify your quality problems.

-Cory


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