Also to get 100x time lapse you may have to rerender and re-compress a few times. So render at the best quality format and higher bitrate than your final.
Steve is right, but I think he may have meant the 'Ctrl' instead of 'Alt' key. Byron is right also, as far as having to render numerous times to get to 100X, as I believe it will only speed it up 400%. Let us know. Cin