Were they streaming real-time? I could only find that they are hosting their videos on https://media.emacsconf.org (would be interested to know who the host is and how much it costs to host videos in this way).
Hosting videos is trivial, especially for a relatively low-traffic event like this. Getting a dedicated host with unlimited traffic (like what Hetzner offers), you usually get a 1G uplink or better, should be able to host it no problem. Under 100 USD/month should be doable.
