[daltore]

Mp4 isn't quite what you might expect. There are several different types of mp4 formats, all under the name "mp4" because it's not video file, it's a container - it only stores the video and audio media streams in certain external formats. You have to find out which formats the iPod actually supports so you can convert into those formats. I believe it supports h.264 as the video encoder, and then use whatever audio format is the default for the program, because it works. To set the encoder, find the settings, then find something that says "video encoder". There should be a list of available encoders to use. And always remember that Google is your friend.