The question you have to ask is HD just a matter of resolution? Remember that each pixel should carry the information as to its colour and luminosity...
So the information each frame has to carry is 1920 x 1080 x 8 x 8 x 25 bits of info per second, SO a HD picture would large even with compression and video too big for the internet
That's why there is now real HD on the internet.... HD is a con and a sales technique....
http://www.zdnet.com/blog/ou/why-hd-...-a-big-lie/511