I have a LCD projector with a native res of 800x600 connected via RGB
So on your projector you have 4/3 aspect ratio, on 16/9 content (HD) you get 800x450.
HD 720p content shows smaller, in the middle of the screen but looks amazing HD 1080i as well only fills the center of the screen and has
Because SD works full screen, I think this is something what downscaler does. Have you tried multiple xineliboutput settings? How about xinelib settings if any?
bad interlacing artifacts regardless of the deinterlacer settings I use. My video card is a nvidia 5500
I think with XVMC you don't get deinterlacing, because you forward sort of mpeg data to video card, and if videocard cannot do proper deinterlacing. Starting from Nvidia 6600 there is purevideo hardware deinterlacers which work ok on Windows side.
On possible direction would be investigating xv_deinterlace if that can be used. But probably not with XVMC.
BR, Jori