[mythtv-users] Jittery playback after moving from .11 to .14

[Leif Pearson]

I recently rebuilt my MythTV box to move from .11 to .14 and have found that
the playback on live and recorded TV is jittery. What I mean by jittery is
that every 5 seconds or so, the playback seems to skip a few frames, or play
them in fast-motion (hard to tell which).  The sound manages to stay
in-synch with the video.  One other problem is that commercial skip doesn't
work very well - it will catch the first or second break, but as the show
progresses, it is less able to flag commercials.  Playback and commercial
skip both worked great under my .11 setup.

I suspect these two issues are related, and am hoping someone out there has
some ideas. For what it's worth, I am not very experienced with Linux, just
experienced enough to setup a MythTV box with a reasonable amount of
head-banging.

Here are my hardware specs:

- Shuttle SB51G mobo
- 2ghz P4
- WinTV Go capture card (bt878 chipset)
- Nvidia MX 440SE video card (64 MB, I think)
- This is a dedicated MythTV box, so there's nothing else eating CPU

Software Specs:
- Fedora Core 1
- Axel Thimm's 2.4.22-1.2174.nptl_37.rhfc1.at kernel
- Followed Jarod Wilson's terrific guide for installation, pretty much
followed it exactly

I haven't changed any of my HW configuration since I had things up and
running under .11, so the only major changes are software related.  The
major changes in software are:

- Running under Fedora instead of RH9
- Installed using Jarod Wilson's terrific guide (as I did for .11), but for
14 I took advantage of Axel Thimm's ATrpms kernel, including the custom
video drivers that I believe he created.  I wasn't able to get the Nvidia
driver from Axel's .11 kernel to compile and play nicely (kept crashing), so
I used as much of Axel's ATrpms as I could, and then installed the Nvidia
drivers from the Nvidia website over the top of his ATrpms.

The areas that I am most suspicious of are a) the custom Nvidia drivers, and
b) changes in MythTV from .11 to .15.  I have scoured the archives for
ideas, and tried most of those (messing with video recording quality, all
the options in the front end), but to no avail - no matter what I tried, the
jittery playback was still present, and the commercial skip didn't work very
well.  I've gone back to the standard settings that are in place when MythTV
is first installed, and have found those to perform the best (in other
words, I don't believe I need to have a funky configuration to make this
work).

Does anyone have any thoughts on what I could try next?  I'm thinking that
going back to the stock Nvidia drivers is the most prudent next step, but
wanted to see if anyone else had experienced similar problems.

Thanks alot,

- Leif