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.

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

In general, user interfaces for controlling a plurality of multimedia players in groups are disclosed. According to one aspect of the present invention, a user interface is provided to allow a user to group some of the players according to a theme or scene, where each of the players is located in a zone. When the scene is activated, the players in the scene react in a synchronized manner. For example, the players in the scene are all caused to play a multimedia source or music in a playlist, wherein the multimedia source may be located anywhere on a network. The user interface is further configured to illustrate graphically a size of a group, the larger the group appears relatively, the more plays there are in the group.

User Interfaces for Controlling and Manipulating Groupings in a Multi-Zone Media System

Example systems, apparatus, and methods receive audio information including a plurality of frames from a source device, wherein each frame of the plurality of frames includes one or more audio samples and a time stamp indicating when to play the one or more audio samples of the respective frame. In an example, the time stamp is updated for each of the plurality of frames using a time differential value determined between clock information received from the source device and clock information associated with the device. The updated time stamp is stored for each of the plurality of frames, and the audio information is output based on the plurality of frames and associated updated time stamps. A number of samples per frame to be output is adjusted based on a comparison between the updated time stamp for the frame and a predicted time value for play back of the frame.

Systems and methods for synchronizing operations among a plurality of independently clocked digital data processing devices without a voltage controlled crystal oscillator

Technology for grouping, consolidating, and pairing individual playback devices with network capability (players) to stimulate a multi-channel listening environment is disclosed. Particularly, the embodiments described herein enable two or more playback devices to be paired, such that multi-channel audio is achieved. Such embodiments may be used to produce stereo and multi-channel audio environments for television and movies.

Multi-channel pairing in a media system

In a system for distributing data, distribution device is configured to distribute timestamp, offset and source location information for a digital data stream to an execution device, and the execution device is configured to seek digital data corresponding to the received information. The execution device is further configured to execute the digital data relative to a clock rate maintained by the distribution device. Related methods include receiving timestamp, offset and source location information for the digital data stream and seeking digital data corresponding to the received offset and source location information.

Systems and methods for synchronizing operations among a plurality of independently clocked digital data processing devices that independently source digital data

The present invention provides an improved clock synchronization algorithm for a distributed system intended for real time applications by performing at the same time an off-set correction and a clock read correction at each node of the distributed system. Expensive oscillators can be avoided and synchronization can be established faster and with higher precision.

Mathias Rausch

Papers

Clock synchronization in a distributed system