FFMpegX Output files

[Dearg800]

Hi a dumb question maybe.

Since I like cover flow on itunes I want to put all my movie/avi files into it. I know for some apple reason I can only load in mpeg4 files. so in future I'll rip dvds as mpegs. but for those, ahem, legitimate backups files I have i'm using ffmpegx.

the question i have is that I'm getting different size output files. Since most of these avi files are 700mb, when i convert them into mpeg4 they vary in size from 580mb to 880mb due to my fiddling about. Is there any way of limiting quality loss and controlling the size of an output file i.e. an 700mb avi files becomes an 700mb mpeg4 file?

The 580mb is defo losing quality and the 850mb file is fine but I've only 60gb hard drive for all my files.

[Dearg800]

okay scratch that. I used the option ffmpeg encoder rather than mencoder and it worked nearly fine lol.

A quick question then. Am i losing quality converting a 700mb avi file to a 700mb mpeg file or is this the difference barely noticeable?