A short update.
I put 20 Keynote slides into iMovie, recorded voice-over narration into Garageband and shared into iTunes as .aif, from where iMovie imported a voice track. With another track for Keynote slides and another of course for the Jupiter music ;-) this ten-minute iMovie was then compressed from 440MB in Quicktime to 6.6MB as .mov
The compression 1.5% is similar to that achievable by Impatica.
However my thoughts on all this are that the topic must be suitable for the very small screen 320x240 at the outset. Text itself is hardly legible, after compression, though voice-over is fine. This might suggest that students listen to the compressed movie with their textbook open ...
Reusable Learning Objects must be better designed than this.
Comments do get here through Blogger who email them to me for accepting (all so far).
All Best Wishes
Here is the clickable screen-grab for the Mac Keynote compressed