hagai,
there are only two possibilities to watch HD-content on computers:
1.) as file-format (MOV/AVI/MP4/WMV, or whatever)
2.) created as Blu-ray disc with a blu-ray-playback software
the old format HD DVD was killed by blu-ray aprox 3-4 years ago during the HD-format-war.
so the only way to watch a BD or a BD-folder on computer is to buy specific software like arcsoft theater or winsoft player.
as steve jobs didn´t like blu-ray, apple never released a software-BD-player for mac os.
so these are the two options that you have, no more, no less.
if your customer recommending an HD-film on disc – blu-ray is the only way to go, and your customer needs to live with it.
cheers
danny