Video Looping Problem

how did you loop it? is this a rendered video? did you use an expression? are you first and last frame identical?

if you imported a rendered video and want to loop it, go to the interpret footage dialog (right click on the footage item in the project panel->interpret footage->main and at the bottom choose how many times you want to loop. this will be a repeating pattern loop where Ae assumes your first and last frame are not identical but instead the animation ends one frame before the first frame. so it repeats...

if you want to loop a live composition then precomp your animation and use Time-remapping:

to make a repeating pattern loop (first and last frame not identical) do this:

1. create the TR keyframes

2. go to one frame before the last frame and create a keyframe

3. copy the first keyframe over the original last keyframe.

4. add this expression loopOut()

to make a seamless loop (first and last frame identical)

1. create the TR keyframes

2. go to one frame before the last frame and create a keyframe

3. delete the last keyframe

4. add this expression loopOut()

a discussion about it here: Re: LoopOut Composition not working