It would be most interesting to know why they aren’t doing it on the server side.
The adtech vermin do have a lot of congratulatory writeups of “server-side ad insertion” and its benefits; and doing it that way certainly does defeat standard client side adblocking approaches; as well as simplifying the client side of the video playback since it no longer has to do anything except play back the stream it is fed.
I can only assume that doing it that way imposes higher encoding costs, makes caching harder, or otherwise increases difficultly of delivery; because from the perspective of playing whack-a-mole with untrusted clients it’s obviously preferable.
