[mythtv-users] Refresh line being seen

Paulin paulin at spextreme.com
Sun Feb 15 01:59:50 UTC 2009

On Sat, Feb 14, 2009 at 2:54 PM, MrVining <myth-user-discussion at mrvining.com
> wrote:

> On Feb 14, 2009, at 12:58 PM, Paulin wrote:
> On Sat, Feb 14, 2009 at 1:35 PM, Allen Edwards <allen.p.edwards at gmail.com>wrote:
>> On Sat, Feb 14, 2009 at 10:22 AM, Brian Wood <beww at beww.org> wrote:
>>> On Saturday 14 February 2009 11:02:41 MrVining wrote:
>>> > On Feb 14, 2009, at 9:26 AM, Paulin wrote:
>>> > > I'm having an old problem reappear after upgrading the NVidia
>>> > > driver and then downgrading.  Can't seem to figure it out.
>>> > >
>>> > > 1. Upgraded to 180.22 NVidia driver.
>>> > > 2. Eventually downgraded back to 180.16 driver.
>>> > > 3. Put the .nvidia-settingrc file back from before the upgrade
>>> > >
>>> > > Now whenever watching a recorded program there is a thin line
>>> > > scrolling down the screen every minute or so.
>>> > >
>>> > > Can anyone tell me what I should be looking at to correct this.  I
>>> > > thought it was caused by the Nvidia settings but since they are
>>> > > back to what they were before I updated/downgraded the driver I'm
>>> > > not sure why it's happening.
>>> > >
>>> > > Any help would be appreciated.
>>> > >
>>> > > Thanks,
>>> > > steve
>>> >
>>> > Is it possible that it is not driver related?  Has there been any
>>> > physical changes made to the system.  I hear line slowly scrolling
>>> > down the screen and I still jump right to grounding issue (retired
>>> > cable guy).
>>> With NTSC at least, a horizontal line scrolling slowly *up* the screen
>>> indicates 60 or 120 Hz. hum. The rate is the difference between the
>>> vertical
>>> rate being precisely 60Hz, and what it really is with NTSC color (in
>>> other
>>> words, if 3.579545 was in fact 3.600000, then the bar would be
>>> stationary).
>>> A grounding issue would thus create a moving up bar, unless the scan rate
>>> of
>>> the video was far enough from 60Hz. to create a downward motion of the
>>> bar.
>>> I tend to agree that the OP does not have a driver issue, more likely
>>> some
>>> sort of interference in the machine itself, the monitor, or the cabling,
>>> or
>>> some sort of common mode (ie: grounding) problem.
>>> --
>>> beww
>> By ground problem, likely it means that there is a difference between the
>> computer ground and the TV ground.  So, in this case you may not have done
>> anything to the computer but if you plugged the TV in to a different slot or
>> changed your antenna setup it could explain it.
>> If you have cable, it could even be that the cable guy came by while you
>> were not looking and grounded the feed.
>> I had to run power from my projector to my surround setup to get rid of a
>> line like that. Now everything is on the same circuit.  I also ground my
>> antenna to that same sub panel.
>> Allen
> OK now I'm even more confused.  Sorry :)
> Anyway this setup has been this way for a few months (November) and working
> until yesterday night when I did a few things to the box (removed GNome
> Network Manager, Attempted to upgrade the NVIDIA driver to 180.22, and
> rebuilt trunk.
> The Myth Box (Backend/Frontend) was not really touched other then to plug
> in a CRT for some initial work with the Driver setup.
> The box is plug into a surge protector power strip that the stereo, TV, DVD
> and TIVO are all plugged in.  The cable coming in, is split (3-way) and
> feeds the Tivo, and the two tuner cards in my mythbox.
> The line that I have scrolls down only.  When I first configured my MythBox
> I had this issue and it was fixed when I got the NVidia settings correct.
> That may have been a cooincent.
> If fixing the grounding issue what part should I look at changing.
> Thanks and sorry for my ignorance.
> steve
> My method for trouble shooting grounding problems was to remove as many
> things from the equation as possible (everything connected to TV or
> computer).  Use the computer to playback a recording, if the bar is gone,
> reconnect your equipment one by one and watch for the bar to come back.

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

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.

I think it's a playback issue and possibly a deinterlace issue.  But I'm
definately no export and looking for ideas.

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mythtv.org/pipermail/mythtv-users/attachments/20090214/fe70849f/attachment.htm>

More information about the mythtv-users mailing list