Hi Mark<br><br>Nice summary, thanks for feeding back to the group your problems and solutions.<br><br>Cheers<br><br>Shannon<br><br><br><br><div class="gmail_quote">On Mon, Mar 3, 2008 at 9:03 AM, Mark van Dijk <<a href="mailto:mark.van.dijk@ihug.co.nz">mark.van.dijk@ihug.co.nz</a>> wrote:<br>
<blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">QUICK SUMMARY:<br>
Hi all, about 1 month ago I asked for some help to fix my very poor<br>
picture quality issues. Thanks to several helpful replies I have now<br>
finally fixed up the issues. I thought i'd just detail what I found<br>
just in case it might be useful to anyone else in the future.<br>
<br>
<br>
ORIGINAL SETUP AND PROBLEM:<br>
Mythbuntu, AMD 2400+, 1GB RAM, GeForce 4 MX440, S-Video connection to a<br>
decent PAL widescreen TV. Using nVidia binary drivers, the card was<br>
using TwinView mode running at 1024x768. My CRT was excellent, but the<br>
picture on my TV was appalling! My original email detailed several<br>
aspects of very poor picture problems - namely:<br>
1) a 'comb like' interlacing effect, except that instead of hundreds<br>
of comb teeth, there were only about 20.<br>
2) a faint (but very annoying) diagonal shimmering over the TV<br>
3) TV appeared to have a resolution of approx 240x160 - FAR less<br>
than the 720x576 than i would expect. All text was virtually<br>
unreadable.<br>
<br>
<br>
SUGGESTIONS:<br>
Several helpful people gave me some good suggestions (Steven Ellis,<br>
Steve Hodge, Wade Maxfield, Daivd Lowe, and others):<br>
1) run at 800x600 instead of 1024x768. this made almost no difference<br>
2) turn on BOB de-interlacing. this improved things a little. the<br>
comb effect was reduced - but not eliminated. Other problems<br>
remain.<br>
3) check the TV settings for brightness/contrast/sharpness/etc<br>
4) unplug the CRT. no difference.<br>
5) try a different video card. this ultimately did the trick<br>
<br>
<br>
SOLUTION:<br>
I bought a GeForce FX5200. After some playing around, everything worked<br>
properly. In particular, i had to:<br>
1) remove and reinstall the nVidia binary drivers (using the Envy tool)<br>
2 modify xorg.conf with - Option "UseEvents" "True"<br>
3 now running in true 720x576 mode<br>
4 CRT is not connected and TwinView is disabled<br>
<br>
At this point I mostly had a very good picture on the TV. The<br>
interlacing effect was gone, the diagonal shimmering never occured with<br>
the FX5200, and the resolution of the TV seems fantastic (given that it<br>
is only being run at 720x576)!!! Even running a normal Ubuntu desktop<br>
is (almost) usable via the TV. fonts are as clear as can be expected.<br>
<br>
There were still two major issues left at this point:<br>
1) the picture through my myth box appeared to lack dynamic range -<br>
anything dark on the screen appeared completely black. no matter<br>
how much i played with the TV's brightness/contrast settings, i<br>
could not get a very good picture.<br>
2) unusual issue where if i start watching TV through Myth, the<br>
picture was ok. If i then pause the stream and resume, the<br>
picture was very stuttering and jerky. This was reproducable<br>
every single time.<br>
<br>
After some more playing around i discovered:<br>
1) that Myth itself has brightness/contrast settings that were<br>
set all wrong. I reset these settings.<br>
2) I turned OFF de-interlacing in Myth. This fixed the pause/<br>
resume stutter issue. As a bonus, all of Myth's overlay<br>
menus are now crystal clear (with de-interlacing ON these<br>
overlay menus flickered very badly).<br>
<br>
<br>
SUMMARY:<br>
I now have EXCELLENT picture quality on my TV. The picture through Myth<br>
is now basically indistinguishable from watching direct on my TV. In<br>
retrospect, I think that there was just something physically wrong with<br>
my old video card. Other people have successfully used the MX 440<br>
cards...<br>
<br>
I still have several more questions about Myth, but that can wait for<br>
another email<br>
<font color="#888888"><br>
<br>
--<br>
Mark van Dijk<br>
<br>
_______________________________________________<br>
mythtvnz mailing list<br>
<a href="mailto:mythtvnz@lists.linuxnut.co.nz">mythtvnz@lists.linuxnut.co.nz</a><br>
<a href="http://lists.ourshack.com/mailman/listinfo/mythtvnz" target="_blank">http://lists.ourshack.com/mailman/listinfo/mythtvnz</a><br>
Archives <a href="http://www.gossamer-threads.com/lists/mythtv/mythtvnz/" target="_blank">http://www.gossamer-threads.com/lists/mythtv/mythtvnz/</a><br>
</font></blockquote></div><br>