[mythtv-users] My Perennial Problems with XvMC

Dylan Semler dylan.semler at gmail.com
Tue Sep 19 20:31:32 UTC 2006

New developments:

So I went to watch LiveTV yesterday on a different, remote frontend
(ati card--no xvmc).  I was watching an SD channel and was getting the
picture deterioration problem on that as well!  However, it wasn't
like on the BE/FE machine as it only lasted a few seconds and occurred
about once ever 30 seconds.  I chalked it up to the fact that the BE
was running a comflag job and the processor couldn't keep up.  So I
turned of the comflaging and went back to watching TV.  10 minutes
later, the deteriorations happen again.  Same thing as before.. only
ever 30 seconds or so and only lasting about second each.  And then it
hits me.  This pattern corresponds exactly with when the screensaver
is drawn on the BE monitors.  I had it set to the space scenes and
every 30 seconds or so it draws a new image from space onto the
screen.  Thinking back on it, as I was watching a football game last
sunday on a remote frontend and browsing the web on the BE at the same
time, every time I scrolled a web page or opened a new tab, I would
get short distortions while the screen was changing.  The
deteriorations seem to be recorded into the mpeg files, as watching
the recordings again show the deteriorations happening at the same

So it would seem the problem is when the pcHDTV is recording and the
graphics card is drawing something on the screen, and the distortions
exist in the recorded mpeg file.  Since this occurred with the GeForce
4200 and the 6200, it may be a problem with my HD-3000.  Or maybe a
bus bandwidth problem?  I don't know.  I didn't see the deterioration
when I was playing with myth last April, but I have moved the computer
quite a bit since then.  Is it possible something broke on my tuner

I guess it's not really an XvMC problem at all--which explains why
mplayer was not having the same issues.

By the way Norm, thanks anyways for taking the time to help me
troubleshoot the XvMC step-by-step.  Thankfully we won't be having to
scrutinize our way through all those options now.


Type faster.  Use Dvorak:

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