In this example, the first fixed heading is set inside a 55% height container that is set inside another 100vh fixed container. We then set an interaction whereby when the parent of the second heading scrolls 55% up into view we;
1. fade in the bg video
2. set opacity of the first heading to 0% with no transition
3. set opacity of the second heading to 100% with no transition
The interactions give the effect of a fixed heading that starts scrolling when the other content comes into view.