How is video streaming load balanced?

Question

Video broadcast

Day in the hut, cats!
I decided to become a competitor to Google and file my own YouTube, but I ran into some misunderstanding of the process.
Introductory:
There is a server, on which a video stream is poured from a mobile device, which anyone can watch through a video player located on a web page. Well, there are a lot of people wishing - at the same time from 100k and more.
Questions:
1. How is the load balanced?
2. Does it make sense (and is it possible?) to use a CDN to reduce delays for users from different regions of the world?

Answer 1

1. CDN
2. has

Answer 2

1. You can build your own delivery network.
Then you need a balancer , but here there are still alternative options.
For example GEO DNS or a choice on the client.
2. If you broadcast using segmented protocols, then CDN is an easy and good option to start with.
If you need low latency streaming, then you need to build your own delivery network.
Because large networks will not offer this, and specialized services are expensive.