Mobile group conferencing with portable devices

A master device (e.g., a laptop) controls a videoconference connection with a far-end and acts as a controller for slave devices in a group. The master establishes the connection with the far-end using a wide area network and connects with the slaves using a Wi-Fi connection of a local area connection. To connect to the slaves, the master outputs an ultrasonic beacon encoding the master's address in the local network. The beacon also allows differences in the various clocks to be handled during audio processing. During the videoconference, the master outputs far-end audio to a loudspeaker and sends the far-end video to its display and to the slaves. Each device captures audio/video with its microphone and camera. The master determines which captured audio is a dominant talker's and may only send that audio to the far-end. The video associated with the dominant talker's device may also be sent to the far-end.