This screencast gives an overview of how to use Twixtor within Final Cut Pro X, to do a SpeedRamp and Fit-to-Fill. You will see an example of the Frame number and Speed option in Twixtor.

Special Thanks to Mark Tekushan for allowing us to use the sailing footage. www.mfxs.com 

Special Thanks to Jesse James Jones for allowing us to use his car footage. www.Jesse.com