[Nevik Mcclure]

I know this is an old post but it might help someone. Here is what I did:

I have two clips in a Premiere Pro CS6 project (m2ts) that I want to use timewarp on. I imported the project into After Effects. I increased the duration x2 (Composition/Compostion Settings/Duration); turned each clip into a PreComp (Layer/Pre-Comp/Move all attributes into the new composition). Then enabled time remapping for each clip and then added timewarp.

I found that I had to reduce the speed to 25% to get 50% (sometimes) but it worked. It still needed fiddling i.e. drag the end of the clips to the desired length but I got the darn thing to work.

When working on 2+ clips in a project I found that after the first clip, when I added Timewarp, I get a black screen. What happened is that the scene went massively to the right in the time line. What I did here was to find where the clip ended in the time line and compress the time line to the clip size (grab the very end of the time line and drag it left or right). Then set the warp to 100 and then decrease it by 5. At each decrease I would have to drag the right end of the time line out. I would repeat this process until I got to 50.