[mythtv-users] M10K XvMC video stuttering

[Michael Carland]

On Apr 16, 2005, at 3:50 PM, Michael Carland wrote:
> With both XvMC’s enabled (or just the VIA one), and deinterlace Bob 
> (2x framerate), the picture looks great, but there are bursts of 
> “prebuffering pause”s and “WriteAudio: buffer underrun” messages that 
> go along with stuttering video.
>
> With both XvMC’s disabled, no deinterlace, there are no pauses, no bad 
> log messages, but there is video tearing.
>
> With both XvMC’s disabled, and bob deinterlace, video is shown twice, 
> split screen, with same picture squished on the top and the bottom, 
> colors are funny (lots of purples and blues), and the whole screen 
> flickers solid green. It’s a little noticable.

I'm still having no luck with this, although I may be wrong that it 
works fine when it is not live tv, it just works much better.

I have put a "-v all" log (it's about 1MB) at 
http://webpages.charter.net/mcarland/mythfrontend.livetv of startup and 
watching live tv for a short time. From the log, it appears XV and XvMC 
are being used. I've also done an strace, and see it opening the XvMC 
library, since the log complains about not finding the nVidia XvMC 
library.  I count 1 buffer underrun and 32 prebuffering pauses in a 28 
second period.

I've bumped down the bitrate to 3500, and that didn't seem to help.

I've tried two different backends, with the same results, and is the 
same in .17 and .18. I did a copy over NFS from the backend to the 
frontend, and saw acceptable throughput. I can't remember exactly how 
fast it was, but it was better than 4MB/sec over a 100Mb link.

Any suggestions on how to narrow this down further?

Thanks,

-Michael