<html xmlns:v="urn:schemas-microsoft-com:vml" xmlns:o="urn:schemas-microsoft-com:office:office" xmlns:w="urn:schemas-microsoft-com:office:word" xmlns:m="http://schemas.microsoft.com/office/2004/12/omml" xmlns="http://www.w3.org/TR/REC-html40">
<head>
<meta http-equiv=Content-Type content="text/html; charset=us-ascii">
<meta name=Generator content="Microsoft Word 12 (filtered medium)">
<!--[if !mso]>
<style>
v\:* {behavior:url(#default#VML);}
o\:* {behavior:url(#default#VML);}
w\:* {behavior:url(#default#VML);}
.shape {behavior:url(#default#VML);}
</style>
<![endif]-->
<style>
<!--
/* Font Definitions */
@font-face
{font-family:Tahoma;
panose-1:2 11 6 4 3 5 4 4 2 4;}
/* Style Definitions */
p.MsoNormal, li.MsoNormal, div.MsoNormal
{margin:0in;
margin-bottom:.0001pt;
font-size:12.0pt;
font-family:"Times New Roman";}
a:link, span.MsoHyperlink
{mso-style-priority:99;
color:blue;
text-decoration:underline;}
a:visited, span.MsoHyperlinkFollowed
{mso-style-priority:99;
color:purple;
text-decoration:underline;}
span.EmailStyle17
{mso-style-type:personal-reply;
font-family:Arial;
color:navy;}
.MsoChpDefault
{mso-style-type:export-only;
font-size:10.0pt;}
@page Section1
{size:8.5in 11.0in;
margin:1.0in 1.25in 1.0in 1.25in;}
div.Section1
{page:Section1;}
-->
</style>
</head>
<body lang=EN-US link=blue vlink=purple>
<div class=Section1>
<p class=MsoNormal><span style='font-size:10.0pt;font-family:Arial;color:navy'>Yea—I
was very aware of the ‘rule breaking’ I was doing… I
origionally planned on putting the computer by the TV and running network to
it. Lets just say that wouldn’t fly for aesthetic reasons—the
computer is a piece of junk with noisy drives and fans, and an ugly case—it
belongs out of sight and the room the TV is in has been decorated nicely and
everything… So I decided to try the video and audio—I really hope I
can make it work—before I terminated the cable as it is now, I put s-vid
ends on the two ends of the spool of cat 5 and ran the whole 100 ft from my
main myth server to the TV and found the picture to be fine; that’s a
Geforce 4 ti4200 while my new box uses an ‘el cheapo’ mx420 that
was lying around—it could be anything you mentioned regarding ground
loops/vga signal differences, but my first try will be a friend’s geforce
fx that’s lying around at work.. if that fixes things, I’ll just be
happy at that.<o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:10.0pt;font-family:Arial;color:navy'><o:p> </o:p></span></p>
<p class=MsoNormal><span style='font-size:10.0pt;font-family:Arial;color:navy'>-will<o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:10.0pt;font-family:Arial;color:navy'> <o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:10.0pt;font-family:Arial;color:navy'><o:p> </o:p></span></p>
<div>
<div class=MsoNormal align=center style='text-align:center'>
<hr size=2 width="100%" align=center>
</div>
<p class=MsoNormal><b><span style='font-size:10.0pt;font-family:Tahoma'>From:</span></b><span
style='font-size:10.0pt;font-family:Tahoma'> mythtv-users-bounces@mythtv.org
[mailto:mythtv-users-bounces@mythtv.org] <b>On Behalf Of </b>Brian Wood<br>
<b>Sent:</b> Thursday, June 08, 2006 10:57 AM<br>
<b>To:</b> Discussion about mythtv<br>
<b>Subject:</b> Re: [mythtv-users] Stupid S-Video Problem Continues</span><o:p></o:p></p>
</div>
<p class=MsoNormal><o:p> </o:p></p>
<p class=MsoNormal><o:p> </o:p></p>
<div>
<div>
<p class=MsoNormal>On Jun 8, 2006, at 7:56 AM, Will Constable wrote:<o:p></o:p></p>
</div>
<p class=MsoNormal><br>
<br>
<o:p></o:p></p>
<div>
<p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><span
style='font-size:10.0pt;font-family:Arial;color:navy'> </span><o:p></o:p></p>
<p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><span
style='font-size:10.0pt;font-family:Arial;color:navy'>Yea- my current setup is
s-video via homemade cable—40 ft of cat 5 with s-video and audio
connectors at each end, running through the walls- I know, sounds like a recipe
for disaster. But my laptop drives a <i>perfect</i> signal from one end
to the other while I have this problem with the myth box. So I am
thinking its either the card or the settings/driver.. I have been using
nvidia instead of nv, but have not tried a whole lot of options for resolution
on my vga port. I was thinking it would be good to try identical settings
and do a clone, but I don’t know how to write xorg.conf for
that—mine does dual screens not using xinerama. It does occur to me
though, that the setup I have upstairs is 1024x768 on s-video and 1600x1200 on
vga—while the monitor downstairs cant run 1600, maybe this setting would
make the interference go away. Do you know how to set up xorg for
clone? Also, can I set the horizsync and vertrefresh of my vga monitor to
match what my tv uses, or might this cause a problem?</span><o:p></o:p></p>
<p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><span
style='font-size:10.0pt;font-family:Arial;color:navy'> </span><o:p></o:p></p>
<p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><span
style='font-size:10.0pt;font-family:Arial;color:navy'> </span><o:p></o:p></p>
</div>
</div>
<p class=MsoNormal><o:p> </o:p></p>
<div>
<p class=MsoNormal>Some things to try:<o:p></o:p></p>
</div>
<div>
<p class=MsoNormal><o:p> </o:p></p>
</div>
<div>
<p class=MsoNormal>Since you get a good signal with your laptop, try moving
your TV set next to your Myth box and connecting it up via a short S-Video
cable, if you still see the problem this will confirm that the problem is not
your home-made cable.<o:p></o:p></p>
</div>
<div>
<p class=MsoNormal><o:p> </o:p></p>
</div>
<div>
<p class=MsoNormal>It is possible, almost probable, that the problem *is* your
cable, and something is different between your laptop and your Myth box, for
example your laptop probably has only one video signal, the S-Video, and not a
differing VGA floating around.<o:p></o:p></p>
</div>
<div>
<p class=MsoNormal><o:p> </o:p></p>
</div>
<div>
<p class=MsoNormal>As you seem to realize, you have broken just about every
rule about video cabling :-) But this doesn't necessarily mean you won't be
able to get it to work.<o:p></o:p></p>
</div>
<div>
<p class=MsoNormal><o:p> </o:p></p>
</div>
<div>
<p class=MsoNormal>It could also be something like your laptop having a
different grounding scheme, in fact it may well be more resistant to common-mode
interference because the power supply is not referenced to your house ground,
or the exact VGA rates of your laptop are just enough different as to render
the problem invisible.<o:p></o:p></p>
</div>
<div>
<p class=MsoNormal><o:p> </o:p></p>
</div>
<div>
<p class=MsoNormal>Changing the resolution of the VGA signal may well help your
problem, the interference will still be there but the rate difference will be
different and thus might well cause it to move through the picture fast enough
to not be noticeable. Changing the rates of your VGA signal will have the same
effect, though setting them to be the same as your TV may well cause an
interfering bar to simply be static, unless you can "genlock" them to
a fixed phase relationship, something beyond most PC systems.<o:p></o:p></p>
</div>
<div>
<p class=MsoNormal><o:p> </o:p></p>
</div>
<div>
<p class=MsoNormal>The README included with the nVidia driver explains how to
set up clone mode, but having the same image on both screens is not the same as
having the same video parameters.<o:p></o:p></p>
</div>
<div>
<p class=MsoNormal><o:p> </o:p></p>
</div>
<div>
<p class=MsoNormal>In short, your cabling arrangement is in all probability the
source of your problems. Rules and standards exist for a reason. The type of
interference you are having is very sensitive to the precise frequencies
involved, if they are close enough to each other (or their harmonics or beat
products are) then you will see visible artifacts, if they are far enough away
from each other the products will move through the picture fast enough to not
be a bother, but they are still there, and could be measured with the right
gear. Differences on the order of fractions of a percent of the sync rates can
make the difference, and these are well within the tolerances of modern video
cards. Simply trying another "identical" card might make a
difference.<o:p></o:p></p>
</div>
<div>
<p class=MsoNormal><o:p> </o:p></p>
</div>
<div>
<p class=MsoNormal>You could always use that cat-5 for what it was meant for -
ethernet, and just put a MediaMVP at your set for about the same cost as a new
video card :-)<o:p></o:p></p>
</div>
<div>
<p class=MsoNormal><o:p> </o:p></p>
</div>
</div>
</body>
</html>