TRMG Creating this data manually keyframe by keyframe would be a really long and boring job and the results may not be very good.
Why don't you look for a special software that can create simple animations and export them in text format?
That guy used Adobe Flash, I had some experience with it and it's a great tool for creating animations.
I watched the video again, he actually exported animations in JSON format, not XML.
So you'll need to parse JSON strings, I'm sure it's doable and still must be much easier than preparing all animations by hand.