It's good to talk about this.
I tested one of these introductory video in campaign mode and I notice that the clip does not work well in the game ouveture
Indeed the ratio 16 / 9 could not fit on the screen format 4 / 3.
So I took the videos one by one and I corrected the problem while reducing the weight of the videos and screen resolution.
It will be less beautiful but still correct.
18 movies intro campaign + Rome title = 478 Mb
So I incorporated all the videos of the campaign mode + the intro of RSII and everything works (version RTW) !

Apparently, nobody has tested ... and I did not get back on potential problems concerning the functioning of video in the beta version of the game.
And on the main video introduction to Rome, I do not know if Elendil finished with ...?!
Thank you for your understanding.