I was applying the Optical Flow filter to some footage I have and I wanted to utilize the animate feature. I clicked the icon (to animate velocity) and set my keyframes to make a "U" shaped valley. Basically it was sped up by 1,000 velocity and I wanted to take it back to 100 for about 5 seconds and then ramp back up. So I set the keyframes and let it render. When it got to the point where I added the keyframes it did not slow down. In fact, there was no variation. I checked the project file again and the keyframes were still there. What am I missing?