You’ll need to run @DBear’s JavaScript functions as timeline actions if you’d like to control the video alongside a timeline. The thumbnails in the main timeline which appear when you drag a video into your scene will only be 1-to-1 if your video and timeline start exactly at the same time, which is a bit tricky to do unless your video has already been played and is cached in memory.
This thread demonstrates how to sync videos to animations: Sync animations to Video & Audio
Hope that helps!