[mythtv-users] nVidia and XvMC

[Todd Ignasiak]

On 11/15/05, greg at nodecam.com <greg at nodecam.com> wrote:
> > When I try to fire up watching live TV with XvMC hardware acceleration
> > enabled, I get an X11 BadAlloc error with my nVidia 6200 TC and XOrg
> > 6.8.2.
> > I'm running a subversion branch with 0.18 fixes, and my system is
> > configured
> > with 2 HD-3000s and the latest NVIDIA x86-64 drivers.  The processor is an
> > AMD Athlon 64 3200+, and I have 1 GB of ram in it.  When I disable the
> > XvMC
>
> Has anyone ever gotten XvMC working on a 64 bit native AMD64 machine?  I
> was under the impression that it just didn't work yet.

I sometimes use XvMC on my x86-64 system.   It does work, though it
has its issues.

My machine is very similar to the original poster's (Athlon64 3200+,
Nvidia FX5200, Nvidia 7676 drivers,  Gentoo x86_64, MythTV svn 7337;
HD3000, Fusion3HDTV, PVR-500).   But, I can get smooth playback
without XvMC running:  libmpeg2=80%user / 10% idle,  Standard
Decoder=60%user / 30% idle, XvMC=25%user / 60% idle.

However, I don't use XvMC very much, because every time an
OnScreenDisplay comes up, the audio stutters until a second or two
after the OSD goes off.   So, every time I skip a commercial, it takes
a while to smooth out.  Other than that, the video decoding works very
well.


As for the OP's "X11 BadAlloc error",  this is a longstanding issue in
the x86-64 NVidia driver.   NVidia has been told about it a long time
ago, but it has remained unresolved for several driver releases (ain't
those closed source binary drivers great!).     The workaround is to
repeatedly try to start an XvMC decoder, after 20+ failures, it will
eventually succeed.  Then, XvMC will work until you restart X11.    I
use an XvMC capable mplayer app to keep trying XvMC until it succeeds.



I should probably look into OSD options, to get rid of the XvMC
problems..  I would gladly take a less attractive OSD in exchange for
smooth playback while leaving lots of CPU available for commercial
flagging or other Linux tasks.