[mythtv-users] MythTV changing 1080p to 1080i

[Ken Scales]

I've upgraded my video card to an ASUS N7600GS, and after much Googling, 
have succeeded in configuring it to bring up a 1920x1080p desktop. My 
Sharp LC-42D64U reports that the source is 1080p.  Both vlc and mplayer 
will play 1280x720p recordings in a window on the screen, or expand to 
fullscreen when selected.  The Sharp continues to report 1080p; all 
seems fine.

But when I start up MythTV, the Sharp reports that the source has 
changed to 1080i.  I've been unable to find what's triggering MythTV to 
change the display resolution.

Is there a file / setting that I haven't been able to locate that MythTV 
uses to decide what display resolution to use, causing it to over-ride 
the current display mode?

Additional info:  I am currently running Mythbuntu 8.04, but have 
disabled ".config/autostart/mythtv.desktop" while I diagnose this 
problem.  Also, under Settings / Appearance / Video Mode Settings, I 
have "1020x1080" selected under all of: "GUI", "Video Output:", and all 
"Output:" settings for "Overrides for specific video sizes".  These all 
seem to be working fine, but in 1080i.

Thanks for any suggestions!
/ Ken