Hello,
That's concerned with your ipod type and the quality of video that you want.there should be a top setting for each type,just check that.
And to choose which video codec?
MPEG4:Fast conversion, large video size(same quality)
H.264:Slow conversion, 50% smaller file size(same quality)
And the same with other settings,generally speaking,the bit rate of video or audio and the sample rate of audio and the frame rate of video, the number is bigger,the quality is better,and the speed is slower,and the play requirement is higher.
so, there must be a choice......