[mythtv-users] Refresh line being seen

[Brian Wood]

On Saturday 14 February 2009 19:25:57 David Brodbeck wrote:
> Paulin wrote:
> > Another question based on this information.  Is this line problem in the
> > recording or in the playback.  If I pause the picture when it happens,
> > the line goes away and shows up as soon as playing.  So that leads me to
> > think playback
> >
> > Also I've noticed that it seems to happen when the picture is very busy
> > (fringe cop lights flashing on the background with a few actors in the
> > foreground).  With this does it still seem like a grounding issue.
>
> If it doesn't show up in still images, it's not a ground loop.  A ground
> loop between the computer and the display would show up all the time,
> even in menus.

Right.

And it would not freeze if you freeze video. If it seems locked to the video 
rate somehow it's definitely not a ground loop.

Actually, if the hum bar were recorded, it would freeze, but that's not the 
type of problem he seems to have. This happens with a ground differential 
between the computer and the cable system, if you are using an internal card 
fed by RF to record, and could also be called a "ground loop".

With a ground problem between the computer and the monitor the bar(s) will 
move as long as the monitor's vertical rate stays the same, no matter what 
the displayed video is doing.

-- 
beww
beww at beww.org