ABSTRACT
In multimedia conferencing, media streams are exchanged between participants upon session establishment by setting up communication channels within a group. By default, each participant receives a combined stream obtained by mixing other participants’ media. Situations arise when one wants to select a subset of the conference participants to whom one’s media is sent or from whom streams are received. Media filters are necessary to configure privacy of the participants in the conference. In analogy to broad-, multi-, any-, and swarm-casting, narrowcasting is a technique for limiting and focusing information streams. Narrowcasting systems extend broad-and multicasting systems by allowing media streams to be filtered-for relevancy control, privacy, and user interface optimization. We describe four narrowcasting commands: mute, deafen, select, and attend-to provide distributed privacy in SIP-based conferencing.
