[mythtv-users] Problem with MythTV/HDTV/nVidia

[Michael Haan]

On 2/21/06, Steve Meyers <steve-lists-mythtv at spamwiz.com> wrote:
>
> Jerry Rubinow wrote:
> > On 2/18/06, Steve Meyers <steve-lists-mythtv at spamwiz.com> wrote:
> >
> >>I've got a Pentium 4 2.8GHz with an nVidia FX 5500 in my frontend
> >>machine.  I'm having a little bit of trouble playing HDTV on it.
> >>
> >>If I don't enable XvMC, but use libmpeg2, I can play 720p without many
> >>problems, but 1080i stutters every 1-2 seconds.  Even 720p stutters once
> >>every 10-15 seconds or so.
> >
> >
> > This sounds like a bandwidth or CPU problem.  What's your CPU usage on
> > the frontend when you're playing back?  Are the FE/BE on separate
> > computers, and if so, how are they connected?  Are your drives using
> > DMA?  Is your video card PCI or AGP?
>
> Since it works fine with XvMC, I don't think it's a network bandwidth
> problem.  For the record, it's a separate FE/BE with 100Mbit ethernet
> connection, the drives (on the BE) use DMA, and the video card is AGP.
>
> My CPU usage with pure ffmpeg (no XvMC) is about 95%, with stuttering
> every second.  With libmpeg2, it is about 85%, with stuttering every 2
> seconds.  With ffmpeg + XvMC, it is 30-40%.
>
> >>If I turn off libmpeg2 and enable XvMC, it plays back with no
> >>stuttering.  However, within a 1-5 minutes, it goes berserk.  The vast
> >>majority of the screen (90-95%) becomes a blocky purple or green.  If I
> >>let that continue, it completely freezes X within 30 seconds.  A
> >>ctrl-alt-backspace will get me out of X, so the computer isn't
> >>completely frozen.
> >
> > This I have no idea on.
>
> I made some other changes over the weekend, and this doesn't happen
> anymore.  The tweaks I made were from this thread:
>
>
> http://www.gossamer-threads.com/lists/mythtv/users/133727?search_string=%2Bxvmc%20%2Bnvidia%20%2Bagpgart
> ;
>
> I'm still tweaking it a little bit, but it's working well for now.  I'm
> going to try some of these suggestions to get the picture quality up:
>
>
> http://www.gossamer-threads.com/lists/mythtv/users/84507?search_string=%2Bxvmc%20%2Bdeint%20%2Bkernel
> ;
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>

I'm working against this myself now with some odd results.

Distro: FC4 x86_64
Kernel: 2.6.15
CPU: AMD64 3800
Myth: 0.19
Video: nVidia 6600GT w/ driver 81(78?)
ALSA: 1.0.11

what else....

Anyway - I'm finally getting sound after upgrading ALSA to 1.0.11.  However,
using xvmc (which was working quite well under 0.18.1) video freezes and
sound craps out - eventually, using my pvr 350 and, nearly immediately using
my hd3000-qam.  What's more, xvmc wasn't reducing the cpu usage for hd and
even sdtv was running it around 95%.  My best results seem to currently be
with Bob 2x deint and ffmpeg.  Even though the cpu is pushed to 95% it's
been running fine for half an hour now with out sound skippping out.

I should preface this by saying I realize the position I'm putting myself in
by running:

Bleeding-Edge:
   Kernel
   ALSA

Latest
   MythTV
   nVidia

and really, I'm just hoping this data point will move us towards a "fix",
but I'm sure this can work better.  Good job to all thus far.
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