Rotoscoping

[1980joey]

I'm rotoscoping a short clip.  I'm wondering why the rotoscop tool works fine when the object I am masking is moving.  Once the subject stop moving the rotoscope tool seems to stop working.  Is this suppossed to happen?

I only have the object moving for about 2 seconds. After that it's just a still shot. But I need it to be masked in order to complete my animation. Any help would be appreciated. Thanks!

[Rick Gerard]

I am a little confused. If you have a video of something moving and then it stops, like a cat walking across the floor, but then it sits at the back door and doesn't move, then there is probably still a little movement in the shot that needs to be compensated for. If the shot is of something mechanical that stops moving and the camera is completely locked down, then as soon as the item stops moving you can trim the layer, pre-compose, then enable time remapping to freeze the last frame.

There is never a need to propagate a mask after the object you are masking stops moving, all you have to do is copy the keyframe where the mask stops moving and paste it at the end of the shot or use the trim or simply time remapping trick to freeze the action at the last moving frame. Rotobursh does not generate standard keyframes so the best option for rotobrush would be to trim the footage so the out point is where the action stops, Pre-compose, Rotobrush, Time Remap, then set a Time remapping keyframe on the last good frame with a matte and delete the other keyframes after that.

[1980joey]

So what I did beforehand was combine all the footage I'm using into one clip in adobe premiere. I have about 2 seconds of moving footage. The rest of the clip (about 15 seconds) I actually took a still image and stretched it so there is absolutely no movement. exported as mp4 and then opened it in after effects.

I am trying to keep everything in one layer for the sake of avoiding problems and confusion when adding effects, etc. So when I rotoscope the first portion of the clip with the movement, rotoscope works fine.  Once it gets to the still part, it only is able to rotoscope frame by frame, which is far to time consuming. I don't want to split the clip or pre-compose. Is there any other way? 

I am a total newbie btw, thank you for taking your time to help!