http://www.youtube.com/watch?v=ZOBeEQrZWd8

Or is it used? I just started Chapter 2 and haven't seen it yet. It would make sense ifthis scene between the ambassador and Geralt took place right after leaving Triss' tent in the beginning and then going together to Foltest.

Can't remember seeing it after three playthroughs. The information it contains is great, as the state of the world of the Witcher is much more clear after watching it.

as far as I know, it was just a promotional video

It is a promotional video indeed ! It's not in the game although it is on one of the extra discs that come with the premium and collectors editions of the game.

Wow. That would have made the plot a lot more comprehensible during my first playthrough.

That is really interesting, I hadn't seen that video before. I actually would have really liked that as the intro video for the game - it is a lot slower than either of the ones CDPR chose (in standard or EE editions), but I think it does a really good job of both acquainting the player with the situation and giving a good feeling for the game.

Its a promotional video, explains the backplot. It would be good if it was in the 'extras' section, because it doesn't really suit the plot for this discussion to actually take place.