Ok I didn't get what you say, but I extracted video from .usm file and it doesn't stutter when played outside the game. So this is bullcrap that tech support mentioned it plays as it was intended. : /
i do fresh install of windows 7 x64 sp1 and i have the same issue...
p.s. if u extract from .USM the video MPEG2 i can play with vlc without any stutter (strange)
.... and all that those of us who experience it require is its acknowledgement and some details what can/will be done about it. Sure, the issue is not game breaking but it is still something that should be investigated and worked on.