I am trying to burn a dvd but have to convert files........?

I have downloaded a movie in flv format via RealPlayer. Because the file is flv, it does not allow me to add it to moviemaker (windows). Because of this, i have used the RealPlayer converter to convert it to ipod Video format - which would be mp4. Still, i had to convert it to wmv file so I can add it to moviemaker in order to edit it. I did all this and i was successful in doing so, however the quality of the video is HQ. it is pretty clear, but it turns out to be...shaky. The sound is intact and everything is fine except the video appears shaky. Why is this happening? How can i fix it?