Getting slow in processing tiem

Hello,
Thanks for developing this amazing toolbox. I have started using this with the aim of detecting facial motion units in a single person face of video recordings. It looks like the processing time per each frame is getting slow as the time in the video goes to the end. Do you see why and how to avoid this? I use a video with about 3minutes long. I use a default detector, detector = Detector().
Thanks!

Start by reproducing the slowdown with the default Detector() on a roughly three-minute video and compare per-frame processing time from the beginning to the end. Trace the video-processing entry point and determine what causes processing to degrade over time; done means processing time remains stable or the cause and workaround are documented.

Written by the indexing model from the issue text.