I just had a google and all I can find is contradictory and misleading - so here is the real shizzle.
First you tube HD is NOT HD it is just better - quite good actually.
To get the HD option you need to upload at 720p res and it appears from the examples that 3mbit is enough. The 6mbit looks the same as the 3mbit to me.
The HD option has a much higher bit rate than the present high quality sd option. It looks better cos of the higher bit rate, not the pixel count.
ALL VIDEO will look much better if uploaded as 720p renders.
So - I reccomend that people upload everything as a 720p 3mbit wmv. It really is that simple. You tube streams ' HD ' at about 2mbit/sec so there is no point in uploading files at a vastly higher bit rate.
From top to bottom. 720x576 1mbit wmv, 720x576 3mbit wmv, 1280 x 720 3mbit wmv, 1280 x 720 6mbit wmv.
This is the 720p 3mbit wmv up loded to you tube - http://www.zaskarfilms.com/Films/VFo...zclip7203m.wmv
This is the raw DV file ( 25mbit so will buffer for ages possibly) - http://www.zaskarfilms.com/Films/VFo...e/rawzomdv.avi
**** When watching tube vids always go to the actual you tube page and refreash to get the 'hd' option. ****
YouTube - test tube 1
YouTube - Test tube 2
YouTube - Test tube 3
YouTube - Test tube 4