[mythtv] testing mythtv-vid branch - questions & problems

Daniel Kristjansson danielk at cuymedia.net
Sat Jun 30 19:38:07 UTC 2007

Note: If you have any more questions, please move them
to the users' mailing list and send me a note, I'll follow
the thread there.

On Sat, 2007-06-30 at 11:38 +1000, Matt Doran wrote:
> > This looks like a bug. Could you note this on the #2287
> > ticket? Just so it doesn't fall through the cracks..
> Done

> I managed to get my hands on a nvidia 7600gs, and it performed much 
> better.... even enabling opengl vsync worked.  On the 6150, opengl vsync 
> caused all kinds of odd problems.
Did you disable the automatic vsync settings in
nvidia-settings? These mess with MythTV's vsync
and also lower video decoding performance overall.

> Although I only tested the 7600gs for an hour or two, I found it to be 
> less stable.   Sometimes it would crash, other when I started playback 
> it would just pause for 1-2 secs play a few frames, pause again, play a 
> few frames, over and over.  If I stopped an restarted the playback it 
> would fix itself up.   So the stability just doesn't appear to be there 
> yet .... but maybe it's the drivers I'm using??
If you were still using the 9xxx ones rather than the two
versions I mentioned then yes it could be the drivers. You
may also need to play around with your XOrg settings, BIOS
settings and nvidia driver args and nvidia-setting variables
to get the best OpenGL performance.

> Does you know what video card would be required to render 1080i content, 
> and deinterlace it?     The nvidia purevideo drivers can do this easily 
> on pretty average hardware.... but I'm not sure how that compares to how 
> mythtv opengl rendering compares.
I'm not aware of any cards that can render 1080i using our
OpenGL renderer, but then again the newest nVidia card I
have is a 6800. nVidia PureVideo is a completely different
beast and is not available under Linux. Not that it is
something we couldn't implement ourselves, it would just
be a few months of work for someone talented to tackle it.

> It's  pretty disappointing that the nvidia drivers are so 
> inconsistent.    Is there any information out there to provide 
> recommendations on the best version to use ... e.g. listing known 
> problems with each?    I've looked but the information is hard to come by.
No, before the last release I tested some drivers and found ones
that didn't appear to have any problems with MythTV, but the ok
ones were all 7xxx release drivers. There are probably islands
of bug-free-ed-ness for MythTV at higher releases, but I'm not
aware of anyone doing exhaustive testing.

> > BTW Make sure you restore your DB after testing, the mythtv-vid
> >     branch does change the DB & DB schema revision number.
> I noticed that it only added 2 tables, so I could just drop those and 
> decrement the DBSchemaVer setting if I wanted to move back to trunk, right?

-- Daniel

More information about the mythtv-dev mailing list