Hello :)
I have a DVD9 with resolution 720x576 and i make a DVDRip with resolution 720x512
Can I make DVDRip with HIGH resolution for example 800x592 without quality loss ?

not if you keep the same AVI size, it will loose in bits per pixel and the picture could result as grainy but you could increase the rip's size so as to keep the same bits per pixel. if you use "gordianknot" you'll be able to set all the correct parameters.

in any case to increase the resolution won't improve the avi quality though. imagine you have a .jpg which is 20 cm x 15 and you increase the width per height, the quality of the picture won't increase.

find "gordianknot" - with tutorials - on www.doom9.org

And she has beaten me to it :) All like lylia says and nothing to add furter. To be honest if I rip em I stick to the original DVD resolution these days meaning 720x(xxx = depending on the gropping) and always go for a bpf of 0.20 or 0.25.  Also, I use the original AC3 or if possible DTS soundtrack. As for the codec I use x264 instead of XviD. OK, you can't put em on a single CD anymore but quality is spot on.

EDIT: see other thread.