Thanks for the reply.
I am using AE7.0.
Just to be clear, is this how I use the expression?
I enable time remapping on my precomp.
Then I paste the expression into the time remap value.
Using this technique, I still end up with blank frames being displayed by the expression. It seems like the expression is doing an on for hold frames, then off for hold frames before it picks a new frame.
What does the number of keys have to do with the expression? By default, when I enable time remap, I get two key frames. I stretch out my precomp length to generate my coverage, then move the last keyframe to the end of the precomp.
Ideally, it would be nice to be able to have the frame fade in and fade out at the end of the hold time. This would be like telling a movie clip to play in flash. I am wondering if this is possible via expressions, or would I be better off doing this in JSX. Presently I am generating my precomp with a JSX.
I guess my JSX would need to look at the list of items in the project window, then pick one and assign it to a layer. Then fade it in an out and save the out time to be the in time for the next picked layer. Continue until coverage time is met.