Back in the old days of the 2010's, most services were using some form of encrypted FTP module to deliver data in "chunks" to end users, as their computer would have to load the file and play it as the chunks arrived. Thus the old "buffering" messages we all used to deal with. But I've been out of the video share game in that regard for a long time, and I couldn't even guess as to what Google uses to deliver video these days.