What a very well done presentation/website. More venues should think about this.
That's the problem.
With a big enough screen, a sticky video with transcript below does make sense. Perhaps only make it sticky when the video starts playing though?
As it is, it just appears as a huge waste of space blocking my browser window...
Some way to collapse the video 'banner' into a smaller area, so we can use the full screen, or nearly, when reading the transcript, would be welcome. Perhaps if you click on the transcript to open the video at that point, it could expand again.
But yeah, agree with you. Particularly in this format, where there's so much value in the transcript below it, it'd be better to not have anything sticky. Like YouTube/Vimeo, where sometimes I go down to continue reading, and leave the video playing on top (off screen).
Regarding the format of the webpage: The video completely blocks my laptop browser window in Firefox v. 31.0, making it almost impossible to read the transcript. Sticky HTML elements on text-content heavy pages drive me crazy. Awhile ago I made a simple bookmarklet that makes me a much happier consumer of such pages. One version of it walks the DOM and unaffixes fixed DOM elements. The other changes them to display: none. You can roll your own pretty easily, or try out the ones I made at StaticDing.org. They both make it easy for me to read the transcript of Ilya's presentation. Without them, I probably would have given up.
Edit: I like what you are doing on mobile since you are hamstrung without many options, maybe on iPad portrait and wider you could go for a 2 column approach with the video on the left in a "sidebar" and the text flowing on the right? Again, just an idea. At any rate what you have is fine and gets the point across and I'm just being picky!