If anybody cares:
The Google Video Player downloads the movie from Googles Server (open a *.gvp with Notepad). Than the player saves a *.gvi file on your harddisk. And this gvi is nothing more than an DivX 4 (OpenDivX) file and MPEG-1 Layer 3 for sound. And 29.9/30 frames, even for PAL videos.

If you ask for who this information is: VideoLan plays this *.gvi without any problems on Windows, Linux, MacOs and other OSs. The only problem is, that you need the Google Video Player to download the .gvi... you can not wget a gvi... but I keep trying :)