Concurrent viewers are counted as number of concurrent connections to one live stream.
The viewers can be any 50, what we count is the number of connection which we get to our end point.
We don't count the users, but what we count is the total number of concurrent connections made. If a user watches the stream for 5 minutes and left then the connection which is made to our CDN is disconnected and you can still more users.
If you are still confused, let us know.