Tweaking MythTV

Brandon Beattie brandon+plug at beatties.us
Tue Jan 2 15:26:24 MST 2007


On Mon, Jan 01, 2007 at 09:07:39AM -0700, Barry Roberts wrote:
> On Sun, 2006-12-31 at 23:39 -0700, Shane Hathaway wrote:
> 
> > On the box I used until recently, compiling in XVMC support helped
> > enough to make *some* HDTV programs watchable.  Most shows still
> > stuttered.  The box had an Athlon 64 3200+ and a GeForce 6200.  SDTV and
> > analog worked very well.
> 
> Yowsers.  I'm getting new hardware, but it's frustrating that I can get
> mplalyer to work OK, but can't tweak mythtv to get by with my current
> system.
> 
> > As a workaround, I set MythTV to transcode all HDTV programs
> > automatically to a lower resolution.  The transcoding takes a long time,
> > but the real problem with that solution is that when the signal fades,
> > the transcoder isn't very forgiving and drops a lot of the recording.
> 
> That's what I'm doing now.  Or just recording with myth and then
> watching with mplayer.
> 
> > FWIW, the new 5200+ CPU with a GeForce 7300 plays and scales HDTV in
> > real time with only 30% CPU utilization, meaning approximately 60% of 1
> > core is in use.  Interestingly, XVMC doesn't reduce the utilization.
> > 
> 
> I have a Radeon 9600pro, so XvMC isn't an option.  I think I can
> scrounge up an old AGP Nvidia card and try XvMC.

Without motion acceleration you may struggle.  Try selecting different
de-interlacing options or turning it off.  You can also select to use
the libmpeg2 decoder rather than mythtv's and that could improve
playback.  The best recommendation is to compile mythtv yourself.
Myth's configure has a --enable-proc-opt (I believe that's the option)
that will build the internal decoder and optimize it for your CPU.  If
you don't do this it's hard to get HD working well on a box like the
3200.  I always recommended a 3400 or 3500 as the minimum for HD
playback and to use an nvidia card.  Let us know how it works out for
you.

--Brandon



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