recording tv best mpeg-4 settings

[exiled350]

i have an older athlon 950 with 448mb ram and windows xp sp2-rtm, with a pixleview playtv pro ultra (conexant cx23883 10-bit). im using showshifter for a dvr and after experimenting ive found that i cant get that great of caps from the tv in mpeg-4 (divx pro 5.1.1) what would be the settings to use for the best results. ive tried wm9 and it drops frames like hot coals. and it starts to drop frames if i try to cap at 352x480 like id like to, but the aspect is way off for some reason, eg || instead of =. ive captured mpeg-2 at 352x480 and it is beautiful with few or no dropped frames, but i cant live with 850mb for a 30min program.

[lordsmurf]

MPEG-4 is not a viable capture format for high quality.
Not yet anyway.

[exiled350]

yeah, ive gathered that. ive found that caping in mjpeg at 640x480 and post encoding is a viable option, but im having problems with deinterlacing. every so often the top of the frame will only have one field, or ill have lines going through the picture. this happens regardless of the cap res or the cpu usage. i got a deinterlacer but havent gotten it to work properly without dropping most of the frames. any ideas?