Let's say I want to apply time warp to a certain period of a clip. Therefore I split the clip into three parts: A, B and C. Then I apply time warp to part B of e.g. 50%. But what happens is that the actual footage is shifted by a factor of two. How to circumvent this behavior? My current solution is to prerender part B, delete the original part B and apply time warp to the prerendered footage. But this is kind of annoying and not very elegant. Anybody knows a better way?
Don't split the layer. Add time remapping instead this wil add two keyframes to the layer one will. One on the first frame of the clip and one at the end.
Scrub UBS to the place where you want the clip to slow down and add a new keyframe. Now move to the point in the clip where you want the clip to return to normal speed. You have not changed the speed yet.
Make sure you have enough time in your comp to slow down the middle part of the clip. Now select the last two keyframes (#3 and #4) and drag them to the right so the distance between the second keyframe and the third is twice as big as it was before you moved the keyframes.
Now the clip will play at normal speed until you come to the first time keyframe. Then because you doubled the distance (time) between 2 and 3 the clip will take twice as long to play back. The speed will be half the original speed.
When end you get to keyftame 3 the clippers will return to normal speed because you did not change the distance between 3 and 4. If you open up the graph editor and view the value graph you will see that the angle flattens between 2 and 3 and then goes back to the original angle after 3.
You can use the pen tool to edit the value so you have a little easing to the speed change.
The last sat step is choosing the right frame blend mode. The right setting depends entirely on the content and framing of the shot. Sometimes Pixel motion gives the best results but other times it makes it look awful. You will have to do some experiments.