"mythfrontend: Fatal IO error: client killed"

Not at home, so here's some ideas I'll try next:

modprobe fglrx
mplayer /dev/video0
mplayer tv://3
mythfrontend --verbose playback
lower screen resolution
disable taskbar always on top

...nope, none of these work. mplayer /dev/video0 gives me:

Cannot seek backward in linear streams!
Seek failed
Cannot seek backward in linear streams!
Seek failed
Win32 LoadLibrary failed to load: avisynth.dll, /usr/lib/codecs/avisynth.dll, /usr/lib/win32/avisynth.dll, /usr/local/lib/win32/avisynth.dll

ATI's Linux Drivers dont support XVMC - that's a bad sign. AIGLX, Beryl, Compiz, MythTV, TV TIME all unsupported. Might be time for an nVidia card.

How to determine if I have XvMC support? Doesnt seem much point, as mythtv.org confirms it.

Found the MythTV Users Mailing List Archive

Andrew Robinson has a fairly good bunch of checks I should do: Watch TV with ivtv and mplayer. Record with ivtvctl and 'cat /dev/video0'.

I should check /var/log/Xorg.0.log, dmesg and /var/log/messages after the crash. Should attempt to set up ssh so I can kill X and recover the session.

Check smart output and do a memtest