System and method for synchronizing operations among a plurality of independently clocked digital data processing devices

摘要

A system is described for maintaining synchrony of operations among a plurality of devices having independent clocking arrangements. A task distribution device is to distribute tasks to a synchrony group comprising a plurality of devices to perform tasks distributed by the task distribution device in synchrony. The task distribution device distributes each task to synchrony group members over a network. Each task is associated with a time stamp that indicates a time, relative to a clock maintained by the task distribution device, at which synchrony group members are to execute the task. Each synchrony group member periodically obtains from the task distribution device an indication of current time indicated by its clock, determines a time differential between the task distribution device's clock and its respective clock and determines therefrom a time at which, according to its respective clock, the time stamp indicates that it is to execute the task.

主权项

1. A method of implementing synchronized audio play back amongst a plurality of audio devices, wherein the method is performed by a computing device, and wherein the method comprises:
receiving control information from a user interface that controls audio playback in a plurality of zones on a local network, each zone containing at least one audio device, the control information comprising a user selection of at least two zones of the plurality of zones to establish a synchrony group, wherein the computing device is further configured to reproduce audio information upon command; retrieving audio information from any of a locally stored digital audio file, a remotely stored digital audio file via a wide area network, and a streaming digital audio service; transmitting to the audio devices of the at least two zones, current clock timing information for a clock of the computing device; and transmitting the audio information and playback timing information to the audio devices of the at least two zones over the local network from the computing device, wherein the playback timing information is generated at the computing device, and wherein the playback timing information identifies a playback time relative to the clock of the computing device, and is for use in playback of the audio information by the audio devices of the at least two zones in synchrony, wherein the audio devices of the at least two zones remain independently clocked during synchronous playback of the audio information.