Scroll autoplay is the new option of FV Player Pro (the paid FV WordPress Flowplayer extension). When enabled, it autoplays the video which is currently in the viewport.
You can learn how to use the Scroll Autoplay function in this guide - How to Create Playlists
Self-hosted
00:44
Vimeo

04:28
Deep Underwater

04:45
Brett Rheeder - This is Home
YouTube

02:47
Slovakia - Little big country
Note: With YouTube hosted videos the video only pre-loads, it doesn't actually start playing.