For all D-Link Web Smart Switches, the default IGMP snooping behavior is flooding to all ports, and will stop flooding to all ports if any of client report join message.
In the DES-1228P firmware 1.20.08, it keeps flooding even a client send IGMP report message for join group.
Here is my environment: 1 VLC media sever, 1 VLC client, 1 wireshark packet capature program, and DES-1228P with F/W 1.20.08.
My multicast address is 239.255.0.1 or 239.255.255.1.
Solution: