I like how Berg used a combination of video and .GIFs in their recent post about the Connbox: Connbox: prototyping a physical product for video presence with Google Creative Lab, 2011 – Blog – BERG
Near the end of the (long but interesting) post, they have a full-length video that shows their prototype in action, but then they show snippets of that video in .GIF format to highlight certain interactions which they thought were worth calling out., like this one:
It’s a taste of what’s in the video. Like the .GIF? Watch the video for more.
This might not be the right approach for your situation, but thought it might be a good option to consider.