One of the pages on that site includes a video of somebody demonstrating a precursor to Microsoft Encarta ("Microsoft Multimedia Encyclopaedia") running on Windows 1.0 in 1987:
https://blueosmuseum.com/videos/video.php?v=msmmen
This thing has full-motion video and 3D graphics while the Windows title-bar and menu-bar are visible on-screen, and I don't understand how that was possible. PCs in 1987 wouldn't have had the power to do all that in software. I can maybe imagine something like a VideoCD with MPEG1 videos might store and play back video, but then how would it be composited with the Windows GUI? A decade later I had a Super VGA card with hardware video scaling, but in 1987?
Digital video was quite a number of years out:
Autodesk flic came out in 89/90. - the famous jolt cola can
Apple shipped QuickTime in late 91
Microsoft shiipped VfW in 1992
Mpeg1 chipsets became common in 1993
1) the video is in mode h 320x200x8. - not a lot of data to move. Even. Then.
2) The title and scrolls bars are fake and fixed like a tv border., like you maximized your browser window. (Not f11 full screen mind you). Stating at 1:15 you see paints and updates inside the window but no scrolling.or other windows.
3 ) The bouncing cube isn’t being streamed back. It’s just a bouncing cube demo trying to one up the Amiga bouncing ball. The cube is bouncing but if yiu look at the face of each cube its static texture map . At the 0:50 you can see a mouse appear and the clicks perturb the trajectory that means it’s not recorded or decoded video.
4) All the other image of JFK etc are just bmps being decoded like web gifs