All the footage has been archived by The Video Game History Foundation, and is available in their public archive. It’s significantly higher quality than in the game.

https://archive.gamehistory.org/folder/934c3e91-4721-49bb-b8...

Oh wow! Yes, those are much better quality than can be seen in the Riven release. I wonder if it's possible to mod them into the Riven rerelease!