[mythtvnz] VDPAU tearing - disable composite script?

[Curtis Walker]

I get the well-described picture tearing using VDPAU (nvidia
285.05.09, tried Geforce GTX260 and GT430, Arch Linux, Myth 0.24, core
i5-750).

The tearing problem affects the top few inches of the picture only,
and manifests as slight distortion of the picture, and only occurs
during fast motion on 1080i feeds (such as the rugby). The generally
accepted workaround is to disable compositiing in xorg.conf
(http://www.mythtv.org/wiki/VDPAU).

However, as I use my mythbox - which is both the FE and BE - as my
main PC, it's a pain to disable compositing (and restart X) just to
watch HDTV without tearing, since I can't then run gnome 3 shell
without re-enabling compositing and restarting X.

Any idea of a shortcut or suggestions for a script to automagically:

1) disable compositing & restart X
2) launch mythfrontend
3) on quitting out of mythfrontend, renable compositing and restart X

Any other workarounds?

I've tried the other renderers and de-interlacers available in the
frontend settings, but none look as nice and smooth as VDPAU High
Quality with Advanced 2x deinterlacer and/or still exhibit a small
degree of tearing.