What program is the best to compress mpg files? Does the quality change after?

Answer 1

you can't compress mpg file it's already compressed, what you can do is convert from one format to another format, from mpg for example to .rm(real video player), you can convert 600 meg file into 100 meg file, and yes the quality will change(poor quality), no point to convert from mpeg to avi cuz the size would be almost the same, what you can do is reduce the frame rate

Answer 2

winavi is a great program

and no the quality should remain the same (it depends how much you compress really)