Hey.
What you are looking at are actually subtitles! The video files for Shogun 2 are in five .pack files (as far as I know). They are named 'movies.pack', 'movies2.pack', 'patch_movies.pack', 'patch_movies2.pack', and 'patch_movies3.pack'.
They use the '.bik' file format. I'm not farmiliar with uploading videos to YouTube, but if .bik isn't on a list of supported container files, you will have to convert it. I have only converted to the .bik format, but if you look at the tool "RAD video tools" you should be able to convert the .bik file to a file that YouTube will accept. (In the multimedia context, a container file is something that contains a video file/video files, an audio file/audio files and occasionally other things like subtitles). Here's the link:
http://www.radgametools.com/bnkdown.htm
Good luck.