Playback Device

Patent metadata

Field	Value
Publication number	US-2021255824-A1
Application number	US-202117306016-A
Country	US
Kind code	A1
Filing date	May 3, 2021
Priority date	Jul 28, 2003
Publication date	Aug 19, 2021
Grant date	—

Abstract

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.

First claim

What is claimed is:

1 . A first data network device comprising:
a network interface; a clock that is configured to provide a clock time of the first data network device; at least one processor; a tangible, non-transitory computer-readable medium; and program instructions stored on the tangible, non-transitory computer-readable medium that, when executed by the at least one processor, cause the first data network device to:
operate in a first mode in which the first data network device is not serving as an audio information channel device for any synchrony group;
receive an indication that the first data network device is to begin serving as an audio information channel device for a synchrony group that comprises at least a second data network device configured to process and output audio, wherein at least the second data network device is communicatively coupled with the first data network device over an asynchronous data network configured to exchange digital data packets, wherein the first data network device and the second data network device each have a different respective clock time;
after receiving the indication that the first data network device is to begin serving as an audio information channel device,
(a) configure the synchrony group to playback audio in synchrony, wherein configuring the synchrony group comprises sending control information to at least the second data network device that (i) configures the second data network device to begin receiving audio information from the first data network device and (ii) configures the second data network device to begin operating as part of the synchrony group for which the first data network device is to begin serving as the audio information channelization device; and
(b) transitioning from operating in the first mode to operating in a second mode in which the first data network device serves as the audio information channel device for the synchrony group, wherein, while operating in the second mode, the first data network device is configured to:
exchange, via the asynchronous data network, first timing information with the second data network device that facilitates establishment of a common notion of clock time for each of the first data network device and the second data network device;
obtain audio content to be played back by the synchrony group;
generate second timing information associated with the audio content for scheduling a future time, relative to the common notion of clock time, at which data network devices of the synchrony group are to initiate synchronous playback of the audio content; and
transmit, via the network interface to at least the second data network device over the asynchronous data network, both (i) audio information representing the audio content, and (ii) the second timing information, thereby enabling the data network devices of the synchrony group to play back the audio content in synchrony.

2 . The first data network device of claim 1 , wherein:
while in the first mode, the first data network device is configured to operate as a playback device that is configured to play back audio content.

3 . The first data network device of claim 1 , wherein receiving the indication that the first data network device is to begin operating as the audio information channel device for the synchrony group comprises:
receiving a request to begin operating as the audio information channel device for the synchrony group from at least one of (a) a controller device, (b) another data network device, or (c) a user.

4 . The first data network device of claim 1 , wherein:
while in the first mode, the first data network device is configured to operate as a playback device that is configured to (a) obtain audio content and (b) play back at least a first portion of the obtained audio content, wherein the audio content transmitted while operating in the second mode comprises at least a second portion of the audio content obtained while operating in the first mode.

5 . The first data network device of claim 1 , further comprising program instructions stored on the tangible, non-transitory computer-readable medium that, when executed by the at least one processor, cause the first data network device, while operating as the audio information channel device for the synchrony group, to perform functions comprising:
receiving a request for the synchrony group to play back the audio content, wherein the audio content is obtained in response to receiving the request for the synchrony group to play back the audio content.

6 . The first data network device of claim 1 , wherein transmitting the audio information to at least the second data network device over the asynchronous data network comprises:
transmitting a first portion of the audio information to at least the second data network device over the asynchronous data network before synchronous playback of the audio content begins; and transmitting a second portion of the audio information to at least the second data network device over the asynchronous data network after synchronous playback of the audio content begins.

7 . The first data network device of claim 1 , wherein transmitting, via the network interface to at least the second data network device over the asynchronous data network, both (i) audio information representing the audio content, and (ii) the second timing information comprises:
transmitting the second timing information in a separate communication from the audio information.

8 . The first data network device of claim 1 , wherein exchanging, via the asynchronous data network, first timing information with the second data network device that facilitates establishment of a common notion of clock time for each of the first data network device and the second data network device comprises:
transmitting the first timing information in a separate communication from one or both of the audio information or the second timing information.

9 . The first data network device of claim 1 , further comprising program instructions stored on the tangible, non-transitory computer-readable medium that, when executed by the at least one processor, cause the first data network device, while operating as the audio information channel device for the synchrony group, to perform functions comprising:
receive, from at least the second data network device via the asynchronous data network, an indication that at least the second data network device has successfully joined the synchrony group.

10 . The first data network device of claim 1 , wherein transmitting, via the network interface to at least the second data network device over the asynchronous data network, both (i) the audio information representing the audio content, and (ii) the second timing information comprises:
transmitting a series of frames comprising the audio information representing the audio content and the second timing information, wherein a first frame includes at least a first portion of the audio information representing the audio content and a first future time relative to the common notion of clock time at which the second data network device is to initiate synchronous playback of the first portion of the audio information representing the audio content, and wherein individual subsequent frames include corresponding subsequent portions of the audio information representing the audio content and corresponding subsequent future times relative to the common notion of clock time at which the second data network device is to initiate synchronous playback of the corresponding subsequent portions of the audio information representing the audio content.

11 . The first data network dev

Assignees

• Sonos Inc

Inventors

• Millington Nicholas A J

Classifications

• H04L65/75

  Media network packet handling · CPC title

• H04L65/613

  for the control of the source by the destination (control signals issued by the client directed to the server or network components specially adapted for selective content distribution H04N21/637) · CPC title

• H04L65/61

  for supporting one-way streaming services, e.g. Internet radio · CPC title

• H04L67/55

  Push-based network services · CPC title

• H04L65/611

  for multicast or broadcast (systems for broadcast or conference H04L12/18; arrangements for broadcast or distribution combined with broadcast H04H20/00; arrangements for broadcast applications with a direct linkage to broadcast information or to broadcast space-time H04H60/00; selective distribution of broadcast services, e.g. multimedia broadcast multicast service [MBMS], H04W4/06) · CPC title