Hi Abhishek,
Yes, 1.1.1.1 is the IP address of the multicast source, that could be a video server. IGMP Version 2 is probably still the most common version.
The location of your sources / hosts really depends on your network design. In a small network, it’s possible that you only see switches where the source/hosts are in the same L2 design. In larger networks, your hosts are on the access layer and the source(s) might be somewhere else, behind some router(s).
The client has to keep track of the multicast groups that it wants to receive, each client only joins 1 (or a few) multicast group(s) so there’s not much overhead there.
Rene