New Discovery - It looks like I should be able to embed an AVI file directly into my Impress Slide. From OOO go to Insert -> Movie & Sound and select the .avi file. May need to install a codec (libavcodec?) first...verification needed. Also to convert the MPEG from PyMOL to an AVI format install ffmpeg and then run
> ffmpeg -i file.mpeg file.avi
A video toolbar comes up when you click on the embedded box where you can select "repeat." The AVI video will automatically start playing when you advance to the slide and continue until you move on.