[mythtv-users] Video problems: vertical jitter, temporal jerkiness, artifacts, pausing

Sasha Z kleptophobiac at gmail.com
Sat Dec 17 20:58:21 EST 2005

My issues:

I've recently fixed up my backend (by switching back to old software,
ie, mysql4)... but I'm still having some playback issues with the

1) Vertical jitter
There is a constant 1px vertical up and down jitter with an
occassional 2 or 3 pixel jitter. It's seriously annoying, and doesn't
just affest the OSD, but the whole screen. It gets a little better
when I switch from bob2x to kerneldeint, but it doesn't eliminate the

2) Jerkiness
The framerate doesn't seem constant There's jerkiness out the ears,
which is especially evident on news tickers. It's not occassional, but
it isn't regular. I don't really know how to better describe this, but
I suppose I could camcorder my TV screen and post the video to make it

3) Artifacts
I get total screen blockiness with random distribution of green and
purple blocks every now and then. There's no entry in the frontend

4) Pausing
In almost every recording, there's at least one series of pauses in
both video and audio. Both will pick up and stay in sync with no loss
in content after an indeterminate length. Each pause will be 1 - 15
seconds in duration, and these series of pauses will last up to a
minute. It's tremendously irritating.

My setup:

I have a Toshiba 34HF85 TV, which I'm driving with an FX5200 card via
DVI --> HDMI.I found a modeline for a 30HF83 TV which seems to work
very well. I have tried with and without denoise3d, with and without
opengl vsync (without is slightly better... go figure). I'm running
8306 SVN, but I've had at problems 1 and 2 since forever (I started
using myth with 0.15) 3 and 4 appeared with 0.18.

The frontend is a homebrew box, 1.5GHz Athlon XP with 512MB of RAM on
an nForce2 motherboard.

The backend is a Dell SC420 2.8GHz P4 with a PVR-150MCE and a PVR-250MCE.

The two boxes are wired on a 100mbit/s network.

Does anybody have any thoughts on these issues? They're killing the
usability of the TV portion of my myth setup. mplayer via mythvideo
works great, as do mythmusic and mythdvd.

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