A method and system for sending a multimedia stream in IP multicast networks are provided. IGMP report data is collected by a plurality of routers. The routers report the IGMP report data to a netflow collection server. The netflow collection server collates the IGMP report data. The collated IGMP report data is forwarded to an encoder coordinator. The encoder coordinator adaptively computes an encoding rate of the multimedia stream. The encoded multimedia stream is sent to a plurality of receivers at the encoding rate.