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 that have independent clocking arrangements. The system includes a task distribution device that distributes tasks to a synchrony group comprising a plurality of devices that are to perform the tasks distributed by the task distribution device in synchrony. The task distribution device distributes each task to the members of the synchrony group 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 the members of the synchrony group are to execute the task. Each member of the synchrony group periodically obtains from the task distribution device an indication of the 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. In a system comprising a plurality of controllers that are communicatively coupled via at least a local area network (LAN) with a plurality of zone players including a first zone player and a second zone player, a method comprising:
receiving, at the first zone player, control information from any one of the plurality of controllers via the LAN, wherein the received control information comprises a direction that instructs the first zone player to enter into a synchrony group with at least the second zone player; in response to the direction, the first zone player entering into the synchrony group with the second zone player, wherein in the synchrony group, the first and second zone players are configured to play back audio in synchrony based at least in part on (i) audio content, (ii) playback timing information associated with the audio content that is generated by one of the first or second zone players, and (iii) clock time information for the one of the first or second zone players, and wherein the generated playback timing information and the clock time information are transmitted from the one of the first or second zone players to the other of the first or second zone players, wherein the first and second zone players remain independently clocked while playing back audio in synchrony; and transmitting, by the first zone player to at least one of the plurality of controllers via the LAN, status information, wherein the status information comprises an indication of a status of the synchrony group.