Supply MULTI format/resolution video like you tube (Projekktor for Wordpress)

Youtube not only has several File Formats, mp4,webm, FLV, 3gp

but most importantly the have several resolutions, this is saving them bandwidth as not to serve a 480p file to a 320p device..

my question is, if i convert to all these for mats/resolutions, how can i embed them all, and make sure the player chooses the right one for the device

Thank!