Playback device

Patent metadata

Field	Value
Publication number	US-10303432-B2
Application number	US-201816181327-A
Country	US
Kind code	B2
Filing date	Nov 5, 2018
Priority date	Jul 28, 2003
Publication date	May 28, 2019
Grant date	May 28, 2019

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 method comprising:
a first zone player operating as a standalone zone player that is configured to play back audio individually rather than in synchrony with another zone player, wherein the first zone player comprises a local clock having a clock time and a clock rate;
while operating as a standalone zone player, the first zone player receiving a request to enter into a synchrony group with at least a second zone player that is communicatively coupled with the first zone player over a local area network (LAN), wherein the second zone player comprises its own respective local clock having a respective clock time and a respective clock rate;
in response to receiving the request to enter into the synchrony group, the first zone player entering into the synchrony group with the second zone player and transitioning from operating as a standalone zone player to operating as a master zone player of the synchrony group that is configured to play back audio in synchrony with the second zone player;
while operating as the master zone player of the synchrony group, the first zone player:
transmitting, to the second zone player over the LAN, clock information for the first zone player that (i) provides one or more indications of one or both of the clock time or the clock rate of the local clock of the first zone player and (ii) enables the second zone player to regularly adjust one or both of the clock time or the clock rate of the local clock of the second zone player to track that of the local clock of the first zone player;
receiving a request for the synchrony group to play back at least a first audio track from a network-accessible audio source that is communicatively coupled to the first zone player over one or both of (i) the LAN and (ii) a wide area network (WAN);
in response to receiving the request for the synchrony group to play back at least the first audio track, obtaining audio information for the first audio track from the network-accessible audio source;
generating playback timing information associated with the obtained audio information for the first audio track that comprises an indicator of a first future time, relative to the clock time of the local clock of the first zone player, at which the first and second zone players are to initiate synchronous playback of the obtained audio information;
transmitting the obtained audio information and the playback timing information to the second zone player over the LAN; and
when the clock time of the local clock of the first zone player reaches the first future time, initiating synchronous playback of the obtained audio information with the second zone player.

2. The method claim 1 , wherein transmitting the clock information for the first zone player to the second zone player comprises:
transmitting a series of clock-information messages, wherein individual respective clock-information messages in the series of clock-information messages includes at least one respective reading of the clock time of the local clock of the first zone player.

3. The method of claim 1 , wherein transmitting the obtained audio information and the playback timing information to the second zone player over the LAN comprises:
transmitting the playback timing information in a separate communication from the obtained audio information.

4. The method of claim 1 , wherein transmitting the obtained audio information to the second zone player over the LAN comprises:
transmitting a series of frames, wherein an individual frame includes a respective portion of the obtained audio information.

5. The method of claim 1 , wherein generating the playback timing information for the obtained audio information comprises:
capturing a reading of the clock time of the local clock of the first zone player associated with obtaining an initial portion of the audio information; and
calculating the first future time by adding a given time delay to the captured reading of the clock time of the local clock of the first zone player; and
generating a timestamp that indicates the first future time.

6. The method of claim 5 , wherein the given time delay comprises a sufficient amount of time to allow at least the initial portion of the obtained audio information to be transmitted over the LAN to the second zone player and processed by the second zone player.

7. Tangible, non-transitory computer-readable media comprising instructions encoded therein, wherein the instructions, when executed by one or more processors, cause a first zone player to perform a method comprising:
the first zone player operating as a standalone zone player that is configured to play back audio individually rather than in synchrony with another zone player, wherein the first zone player comprises a local clock having a clock time and a clock rate;
while operating as a standalone zone player, the first zone player receiving a request to enter into a synchrony group with at least a second zone player that is communicatively coupled with the first zone player over a local area network (LAN), wherein the second zone player comprises its own respective local clock having a respective clock time and a respective clock rate;
in response to receiving the request to enter into the synchrony group, the first zone player entering into the synchrony group with the second zone player and transitioning from operating as a standalone zone player to operating as a master zone player of the synchrony group that is configured to play back audio in synchrony with the second zone player;
while operating as the master zone player of the synchrony group, the first zone player:
transmitting, to the second zone player over the LAN, clock information for the first zone player that (i) provides one or more indications of one or both of the clock time or the clock rate of the local clock of the first zone player and (ii) enables the second zone player to regularly adjust one or both of the clock time or the clock rate of the local clock of the second zone player to track that of the local clock of the first zone player;
receiving a request for the synchrony group to play back at least a first audio track from a network-accessible audio source that is communicatively coupled to the first zone player over one or both of (i) the LAN and (ii) a wide area network (WAN);
in response to receiving the request for the synchrony group to play back at least the first audio track, obtaining audio information for the first audio track from the network-accessible audio source;
generating playback timing information associated with the obtained audio information for the first audio track that comprises an indicator of a first future time, relative to the clock time of the local clock of the first zone player, at which the first and second zone players are to initiate synchronous playback of the obtained audio information;
transmitting the obtained audio information and the playback timing information to the second zone player over the LAN; and
when the clock time of the local clock of the first zone player reaches the first future time, initiating synchronous playback of the obtained audio information with the second zone player.

8. The tangible, non-transitory computer-readable media of claim 7 , wherein transmitting the clock information for the first zone player to the second zone player comprises:
transmitting a series of clock-information messages, wherein individual respective clock-information messages in the series of clock-information messages includes at least one respective reading of the clock time of the local clock of the first zone player.

9. The tangible, non-transitory computer-readable media of claim 7 , wherein transmitting the obtaine

Assignees

• Sonos Inc

Inventors

• Millington Nicholas A J

Classifications

• G06F16/2322

  using timestamps · CPC title

• H04W56/0015

  one node acting as a reference for the others · CPC title

• G06F3/165 Primary

  Management of the audio stream, e.g. setting of volume, audio stream path · CPC title

• H04L67/12

  specially adapted for proprietary or special-purpose networking environments, e.g. medical networks, sensor networks, networks in vehicles or remote metering networks · CPC title

• H04R27/00

  Public address systems (circuits for preventing acoustic reaction H04R3/02; circuits for distributing signals to loudspeakers H04R3/12; {monitoring or testing arrangements for public address systems H04R29/007}; amplifiers H03F) · CPC title