NO!NO!NO!NO!NO!
There is not any Crimson 69-74 footage avalible on DVD or video. And it's a [deleted] , pardon my french, shame. If you're on YouTube, there is some other Crimso footage there, try easy money and Lark's Tongues.
However there is a whole lot of KC 69-74 live recordings avalible ,amongst these is the consert from Hyde Park you talk about. You can find them at the Robert Fripp / King Crimson web-site. And they're all price very reasonebly.
https://www.dgmlive.com/shop/
Let's hope Fripp comes to his senses (or finds enough material to release on a DVD) and puts some footage of the golden Crimson out on the marked.
OH! Nearly forgot, on the ELP Beyond the Beginning DVD, there is a bonus feature where you can see these 30-40 seconds shot with the black and white camra. The studio version of 21.Dude has been recorded over the original sound. Still, a very good DVD.
http://www.amazon.com/Beyond-Beginni...4421961&sr=8-2