I stand corrected. There is a freebie way. However, I value my time and the time it would take to do that and adjust the speed and then undo it all sop it can be adjusted to a different rate. I think the time saved would buy the Twixtor plugin or a full copy of After Effects.

Actually, that's an idea. If it's a one off special effect you want then download the demo of After Effects and do it in the 30 day trial period.

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I'm not young enough to know everything!