[mythtv-users] M2NPV, nvidia/X11 settings

[Steven Adeff]

On 4/4/07, Mark A. O'Neil <mark.a.oneil at dartmouth.edu> wrote:
> On Apr 4, 2007, at 16:57, Steven Ellis wrote:
> >> So here is the problem - and I think - this is less a 'problem' and
> >> more a configuration issue - either for the on board nvidia 6150 or
> >> the recording profile.
> >>
> >> Simply put: playback of the desktop and recorded video is fuzzy,
> >> viewable, but slightly fuzzy, while playback from DVD or DVD-on-
> >> Harddrive media is awesome. This is the case using any of the
> >> outputs.
> >>
> >> I think the issue is resolution interpolation...either at the
> >> hardware/video level, the recording profile, or both. Though I am
> >> thinking it is more hardware than MythTV profiles, as the desktop
> >> itself displays fuzzily - perhaps nvidia/x11 settings are the place
> >> to start?
> >>
> >> The projector has a native resolution of 1280x720 and I cannot get
> >> the 6150 to output that nor can I seem to raise the scan rate much
> >> above 50 even though I have NTSC set in the bios etc....
> >
> > Ok you missed out a couple of things.
> >
> > 1. How are connecting to the projector?
> >
> > 2. I'm assuming you are using MPEG2 PVR cards with the ivtv driver to
> > capture video - what bitrate are you capturing at?
> >
> > If you want 720p resolution you need to use HDMI, DVI, VGA or
> > component
> > cables.
> >
> > For 720p try the following modeline
> >
> >  ModeLine       "1280x720_60" 74.250 1280 1390 1430 1650 720 725
> > 730 750
> > +hsync +vsync
>
> Steve,
>
> 1: The projector is currently connected via the TV-out s-video of the
> M2NPV. I have tested output to the projector using s-video and the
> component outs, but not the DVI, HDMI as I do not have those cables.
> VGA was fuzzy on the CRT monitor I have. Output on the LCD TV (a
> vintage 2006 westinghouse) via s-video is substantially better than
> the CRT vga and s-video to the projector. Possibly not 'perfect' but
> easily readable etc.

Sounds like your mixing connections and display devices and making
assumptions. You also don't mention what resolution your running via
s-video.

What I suggest is to first get 720p(1280x720) and 480i (720x480)
output working via component to the projector (or better HDMI/DVI) as
that should give you the best quality for the menu and SD content like
what your PVR and DVD's play at.
Now, the menu should look crisp at either resolution (though I'd
suggest using 720p for the menu since that is what is native for the
projector) since Myth pre-scales the menu to the desired resolution.
Then you can play with seeing whether you prefer Myth(Xv really) to
scale SD content to 1280x720 or the projector doing it. I suspect the
projector will do a better job of scaling (that's a damned good 720p
projector), so you would want to have Myth output your PVR and DVD
playback at 480i (you can also try 480p and let Myth do the
deinterlacing).

I feel your blurry SD is due to the inherent noise of recording over
the PVR cards compared to the near perfectly clean DVD video,
especially when comparing the two.


> 2: Yes both the PVRs are capturing with the ivtv driver. I am at work
> now and do not have the bitrate of capture (and am not certain where
> to find it, but I'll look into that). I am fairly certain, given I do
> not recall setting/changing it, either in the ivtv install or Myth
> config, that it is whatever the defaults are.

Make sure, given the size of your playback(projector, I'm assuming
100" screen? =D ), that you use 480x480 or 720x480, either should be
find for SD, both have their advantages given the situation, and that
you use a relatively high bitrate, 6000/9800 I think are good options,
some may say overkill, but even at those levels I sometimes notice
artifacting during fast movements (like sports).

> If I am following correctly you are suggesting this may be
> addressable via proper setting of X11, the capture bitrate, and using
> component. I will add the ModeLine you suggest to my xorg.conf.
> Switch to my component cabling and I will also look into what the
> capture bitrate is set to.

heed the signature!
http://www.mythtv.org/wiki/index.php/Modeline_Database#Panasonic_PT-AE900U_Projector


-- 
Steve
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