Sonatora wrote:
already requested alot of times
And it doesn't really work like that, the file you download is a compressed file. osu! will have to extract it into a folder, that folder contains all the stuff for the map including the notes, hitsound and whatnot.
To put it simply, in order to start any map, your minimum requirements are that you must have the hitsounds ready and the notes placed. But to get these files, you will have to download the whole file because it is still packed. In other words, you have no choice but to download the whole file anyway thus having to wait for the file to finish downloading first, then extract it and start spectating.
I don't think the servers can handle video streaming, it already has its hands full providing normal downloads for supporters and the likes.