I am wondering if there is a way to keyframe the speed of a clip over time in the NLA?
Yes. If you get the Sintel DVD, Lee Salvamini goes over hwo he did that with Scales flight cycle… The tutorial may be available online. Look around. Its kind of in depth to go into by text.
Great. Thank you.
Can you at least elaborate on what tools he used to do it?
well, first you need to make the action, in his example, it was a wing flapping cycle. Then he brought it into the NLA editor, and it has an option called “strip length” or something like that. he inserted a keyframe (“i” key) on that value (the “strip length”) which then created an F-curve for the strip length in the curve editor. Then he could insert keyframes, moving the curve up and down, and that would correspond to the speed of the flap cycle.
Thank you. I’ll look into that.