I posted this a while back but thought it worth mentioning here again. My PC isn't the best for "filming" SHIV during a mission, however, I found that using the "replay" function in SHIV and THEN filming that (i.e. using FRAPS) I got a half-decent end product.
To clarify;
Using FRAPS while playing a normal mission caused horrendous framerates but using FRAPS during the game's REPLAY function much, much less framerate hit.
Hope this helps anyone else with a half-decent but not quite top-o-the-line PC!!!