Reduced Switching Delay for Networked Music Performance

• NMP: Networked Music Performance • Ultra-low delay variant of conferencing • End-to-end delays of 25 rather than 150 ms • NMP is not the same as conferencing • Participants prefer to do their own mixing • The MCU should only relay data streams • The MusiNet project • Ultra-low delay audio and video coding • Each participant indicates what it wants to receive • The MCU maintains a stream routing table • Optimized media capture and packetization • What else can we optimize? • Media packets are replicated and forwarded • A relaying MCU costs 20 ms of delay • Multipoint Conferencing Unit (MCU) • Receives data streams from each participant • Too much context switching • Too much packet copying • Mixes all data streams together • Relays the resulting data stream to each participant • Too many packet exchanges