I am trying to add a 3d object to footage using camera track data. In the anim player, the timing is perfect and the animation is in sync with the camera. But once I render it and try to composite it in after effects the render is at least 3 times faster than the anim player and doesn’t match up with the camera at all.
If you guys could help me, that would be great. Thx 
This is thought to be a problem that AE does not recognize the frame rate of the sequence output from the blender.
In Interpret Footage → Main, please make the frame setting the same as the blender.
After effects isn’t the problem, before I put it in after effects the rendered animation is faster than the anim playback
Are all settings fine?
How does the Frame Rate setting differ from the actual pace of play?
Is the rendering frame setting the same as the number of sequences output?
If everything is normal, there is no problem.
I think I’ve figured out the problem, my background video is meant to be 29 frames per second and stop at 239 frames but in blender it stops at 200 frames. Anyone know how to lengthen a background video?
I didn’t understand exactly the content of the question, but if you lack 39 frames for the existing rendering, you can render it from 201 to 239.
If the output is a video, you can output the frame in the same way and connect it to the AE.