[mythtv-users] Matrox G400 DualHead - Live TV is squashed

Joe V joevph at yahoo.com
Fri Aug 1 14:16:00 EDT 2003


Matt,

Thanks for the input.

As a test, I recorded a show on a channel that puts
their station logo down in the lower right corner
(RealTV on TNN).

I put mplayer on the MythTV machine with the patch for
the modified Nupplevideo that MythTV uses.  According
to mplayer, the video was encoded at 480x480.  I get
some interesting results here.

Playing the recording back in MythTV still has the
problem.

If I play the file back in a window (not full-screen),
then I see the entire TV shot, with small borders on
the top/bottom (quite livable), and a larger border on
the left (still not too bad).

The interesting stuff happens when I switch to
fullscreen (by hitting the "f" key) - all of a sudden,
the right side of the video gets chopped (i.e. that
station logo and picture is partly gone), as it is
when watching "live" TV in MythTV.  Because of this,
I'm guessing it has something to do with the Matrox
G400.

I've tried adjusting the horizontal
overscan/underscan, and I just can't seem to get it to
fill the screen.  This happens independantly of my
framebuffer settings (fbset), which I can get to fill
the screen.  I've tried this with and without the
fbset command to see if that had some effect - it
doesn't seem to.

I also tried changing from 800x600 to 640x480 for the
framebuffer in the hopes that I could maybe
over/underscan a bit closer to fullscreen.  Although
the results were a bit better, they still weren't good
enough.

Hmmm...  Also as I watch the resulting video, I'm
noticing wicked artifacting at times (i.e. large
splotches of green/garbage).  This could just be that
I'm not using a powerful enough CPU (it's an Athlon
1.4GHz), the TV card could be going, or maybe it's the
mplayer patch, not sure.  That's something I'll figure
out after I get the TV picture working.

Any ideas?

Thanks,
Joe


--- Matt <matt at solecize.com> wrote:
> I'm going to assume that scheduled recordings have
> the same problem.  If 
> they do, then I believe the problem that you are
> having is caused by the 
> overscan settings on your TV capture card.  You can
> also test this 
> theory by playing the recordings in mplayer,  if I'm
> right the 
> recordings will have a border in mplayer as well.
> 
> I like my G400, the only problem that I have with it
> right now is with 
> the color/saturation; red is way too saturated
> 
> 
> Joe V wrote:
> 
> >Hello all,
> >
> >I know that from searching the archives that
> there's
> >been a lot of talk about the Matrox G400.
> >
> >I configured my G400, using the G200 HOWTO
>
>(http://www.gossamer-threads.com/perl/mailarc/gforum.cgi?post=47700;search_string=g400%20howto;guest=894428&t=search_engine#47700)
> >- note that the URL actually goes into the middle
> of
> >the thread), and it' s working.  I have an image on
> >the second head, and using fbset, I managed to
> center
> >the image and expand it to fit the TV.  I used the
> >exact same modelines (for XFree86) from that HOWTO.
> >
> >This is my fbset command:
> >fbset -fb /dev/fb0 -left 56 -right -75 -upper 90
> >-lower 37
> >
> >The TV in question is a Panasonic (NTSC, I'm in the
> >United States), not sure of the size, but that
> doesn't
> >really matter.  :)
> >
> >Anyway, here's my issue...  The MythTV (0.10) GUI
> is
> >fine, it stretches out to full-screen (800x600). 
> >However, when I start Live TV, the TV image doesn't
> >stretch to fullscreen, there's a black border on
> all
> >sides (the right border being the largest).
> >
> >The capture card I'm using is a bttv card (Pinnacle
> >PCTV Rage I think), and the picture is fine, except
> >for the borders.
> >
> >Is the TV scaling handled in some seperate fashion
> >than the GUI?  I think that I've seen this problem
> >described on the list before, but I don't recall
> any
> >useful solution presented.  I'm wondering if it's
> my
> >particular bttv card, or the G400.
> >
> >It seems that the general opinion of the G400
> (after
> >reading the list archives) is that it's not even
> worth
> >trying for NTSC.  Since this isn't going to be the
> >final hardware configuration I'll be running with
> >(this is more a proof of concept box), I can change
> >the video card later or go with a scan converter. 
> >However, I'm hoping that's not necessary.
> >
> >So, has anybody had this problem and successfully
> >gotten the TV to go fullscreen on the framebuffer? 
> >Or, am I better off with some other form of TV out?
> >
> >Thanks,
> >Joe
> >
> >__________________________________
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