[mythtv-users] Where's the playback bottleneck?

[Jerry Rubinow]

On 1/24/06, Kevin Kuphal <kuphal at dls.net> wrote:
> Jerry Rubinow wrote:
> > On 1/24/06, Robert Johnston <anaerin at gmail.com> wrote:
> >
> >> On 1/24/06, Jerry Rubinow <jerrymr at gmail.com> wrote:
> >>
> >>> If I playback an HD resolution file, I get stuttering, pick a codec, any codec.
> >>>
> >>> If I play it back with mplayer (-vo xv -vc ffmpeg12), also stuttering.
> >>>  If I play it back with mplayer (-vo xvmc -vc ffmpeg12mc), plays back
> >>> pretty much ok.
> >>>
> >>> In all cases, myth and mplayer, CPU is between 20% and 50% (this is on
> >>> a combined front/backend, P4 2.8 Pundit, with onboard VGA disabled,
> >>> using a PCI FX5200).
> >>>
> >>> The fact that I can playback the file in mplayer with xvmc, tells me
> >>> it's not a disk issue, and the fact that mplayer cannot play it back
> >>> smoothly with xv tells me it's probably not a myth issue.
> >>>
> >>> Is it a bandwidth problem in the video card or the bus?  Some BIOS
> >>> setting incorrect?  Does anyone have any suggestions for how to narrow
> >>> it down and tell for sure where the problem might be?
> >>>
> >>> Is anyone using an original (sis-based) Pundit for HD playback successfully?
> >>>
> >> If you can play back using mplayer (and XvMC), it means you can enable
> >> XvMC in Myth and have smooth HDTV playback.
> >> --
> >> Robert "Anaerin" Johnston
> >>
> >
> > Theoretically, yes, but I've tried many different combinations of
> > options (vsync, vblank, audio buffering, etc) and it's just not quite
> > good enough for useability.  Sometimes I get a lockup when starting to
> > play, sometimes it gets a stutter, sometimes it gets out of sync with
> > sound.  Nothing consistent, but perhaps indicative of getting near the
> > same bandwidth limit I'm hitting consistently without xvmc.
> >
> What video card and driver version?
>
> I have trouble with anything other than Nvidia 7676
>
> Kevin

That is, in fact, the very one I'm using (though I've tried a bunch of others).