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

• US 9,195,258 B2
• Filed: 02/20/2014
• Issued: 11/24/2015
• Est. Priority Date: 07/28/2003
• Status: Expired due to Term

• Current Assignee: Sonos, Inc.
• Original Assignee: Sonos, Inc.
• Inventors: Millington, Nicholas A. J.
• Primary Examiner(s): Survillo, Oleg
• Application Number:
  US14/184,935
• Publication Number:
  US 20140181173A1
• Time in Patent Office: 642 Days
• Field of Search: 709/219, 709/231
• US Class Current: 1/1
• CPC Class Codes: G05B 15/02 electric
• CPC Class Codes: G06F 1/00 Details not covered by groups G06F3/00 - G06F13/00 and G06F21/00 architectures of general purpose stored program computers G06F15/76
• CPC Class Codes: G06F 1/12 Synchronisation of different clock signals provided by a plurality of clock generators
• CPC Class Codes: G06F 16/2322 using timestamps
• CPC Class Codes: G06F 16/60 of audio data
• CPC Class Codes: G06F 16/63 Querying
• CPC Class Codes: G06F 16/635 Filtering based on additional data, e.g. user or group profiles
• CPC Class Codes: G06F 16/638 Presentation of query results
• CPC Class Codes: G06F 16/639 using playlists
• CPC Class Codes: G06F 16/68 Retrieval characterised by using metadata, e.g. metadata not derived from the content or metadata generated manually
• CPC Class Codes: G06F 17/00 Digital computing or data processing equipment or methods, specially adapted for specific functions information retrieval, database structures or file system structures therefor G06F16/00
• CPC Class Codes: G06F 3/048 Interaction techniques based on graphical user interfaces [GUI]
• CPC Class Codes: G06F 3/0482 Interaction with lists of selectable items, e.g. menus
• CPC Class Codes: G06F 3/0484 for the control of specific functions or operations, e.g. selecting or manipulating an object, an image or a displayed text element, setting a parameter value or selecting a range
• CPC Class Codes: G06F 3/04842 Selection of displayed objects or displayed text elements G06F3/0482 takes precedence
• CPC Class Codes: G06F 3/04847 Interaction techniques to control parameter settings, e.g. interaction with sliders or dials
• CPC Class Codes: G06F 3/16 Sound input; Sound output speech processing G10L
• CPC Class Codes: G06F 3/162 Interface to dedicated audio devices, e.g. audio drivers, interface to CODECs
• CPC Class Codes: G06F 3/165 Management of the audio stream, e.g. setting of volume, audio stream path
• CPC Class Codes: G06F 3/167 Audio in a user interface, e.g. using voice commands for navigating, audio feedback
• CPC Class Codes: G11B 20/10527 : Audio or video recording; Data buffering arrangements G11B20/12 - G11B20/18 take precedence
• CPC Class Codes: G11B 2020/10592 : specifically adapted for recording or reproducing multichannel signals
• CPC Class Codes: H03G 3/00 : Gain control in amplifiers or frequency changers
• CPC Class Codes: H03G 3/20 : Automatic control H03G3/005 takes precedence; combined with volume compression or expansion H03G7/00
• CPC Class Codes: H04H 20/103 : Transmitter-side switching
• CPC Class Codes: H04H 20/26 : Arrangements for switching distribution systems
• CPC Class Codes: H04H 2201/20 : digital audio broadcasting [DAB]
• CPC Class Codes: H04J 3/0644 : External master-clock
• CPC Class Codes: H04J 3/0664 : unidirectional timestamps
• CPC Class Codes: H04L 12/2854 : Wide area networks, e.g. public data networks
• CPC Class Codes: H04L 65/1069 : Session establishment or de-establishment
• CPC Class Codes: H04L 65/1094 : Inter-user-equipment sessions transfer or sharing
• CPC Class Codes: H04L 65/60 : Network streaming of media packets
• CPC Class Codes: H04L 65/61 : for supporting one-way streaming services, e.g. Internet radio
• CPC Class Codes: H04L 65/611 : 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 Class Codes: H04L 65/612 : for unicast
• CPC Class Codes: H04L 65/613 : 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 Class Codes: H04L 65/75 : Media network packet handling
• CPC Class Codes: H04L 65/80 : Responding to QoS
• CPC Class Codes: H04L 67/1095 : Replication or mirroring of data, e.g. scheduling or transport for data synchronisation between network nodes
• CPC Class Codes: H04L 67/12 : specially adapted for proprietary or special-purpose networking environments, e.g. medical networks, sensor networks, networks in vehicles or remote metering networks
• CPC Class Codes: H04L 67/55 : Push-based network services
• CPC Class Codes: H04L 69/28 : Timers or timing mechanisms used in protocols
• CPC Class Codes: H04N 21/4307 : Synchronising the rendering of multiple content streams or additional data on devices, e.g. synchronisation of audio on a mobile phone with the video output on the TV screen
• CPC Class Codes: H04N 21/43076 : of the same content streams on multiple devices, e.g. when family members are watching the same movie on different devices
• CPC Class Codes: H04N 21/43615 : Interfacing a Home Network, e.g. for connecting the client to a plurality of peripherals home Audio Video Interoperability [HAVI] data switching networks H04L12/2805
• CPC Class Codes: H04N 5/04 : Synchronising for television systems using pulse code modulation H04N7/56
• CPC Class Codes: H04N 9/7904 : using intermediate digital signal processing
• CPC Class Codes: H04R 2227/003 : Digital PA systems using, e.g. LAN or internet
• CPC Class Codes: H04R 2227/005 : Audio distribution systems for home, i.e. multi-room use
• CPC Class Codes: H04R 27/00 : 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 Class Codes: H04R 3/12 : for distributing signals to two or more loudspeakers specially adapted for hearing aids H04R25/407
• CPC Class Codes: H04W 56/0015 : one node acting as a reference for the others
• CPC Class Codes: H04W 84/20 : Master-slave selection or change arrangements
• CPC Class Codes: H05K 999/99 : dummy group

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.

Claims

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.

2. The method of claim 1, wherein the status information further comprises one or both of (a) an identification of a track currently being played by the synchrony group and (b) an identification of tracks scheduled to be played by the synchrony group.

3. The method of claim 2, wherein the identification of a track currently being played by the synchrony group further comprises a name of the track currently being played by the synchrony group.

4. The method of claim 2, wherein the identification of the tracks scheduled to be played by the synchrony group comprises a list of names of tracks scheduled to be played by the synchrony group.

5. The method of claim 1, wherein the status information further comprises one or both of (a) an identification of a zone player that is operating as a master device of the synchrony group and (b) an identification of at least one zone player that is operating as a slave device of the synchrony group.

6. The method of claim 1, wherein the first zone player comprises a master device of the synchrony group.

7. The method of claim 1, further comprising:

the first zone player determining whether it is operating as a master device of the synchrony group, and

wherein transmitting status information to the at least one of the plurality of controllers comprises transmitting the status information to the at least one of the plurality of controllers only while the first zone player is operating as the master device of the synchrony group.

8. The method of claim 7, further comprising:

receiving audio content via the network; and

while the first zone player is operating as the master device of the synchrony group, transmitting the received audio content to at least one zone player that is operating as a slave device of the synchrony group.

9. The method of claim 1, wherein the first zone player comprises a device clock configured to generate clock time information for the first zone player, wherein the second zone player comprises a device clock configured to generate clock time information for the second zone player, and wherein the device clock of the first zone player operates independently of the device clock of the second zone player.

10. The method of claim 1, wherein the first zone player is a master zone player of the synchrony group, wherein the audio content comprises a plurality of frames, wherein the playback timing information associated with the audio content comprises a playback time for each frame of the audio content, and wherein the first zone player is configured to play back audio in synchrony with the second zone player based at least in part on (i) the audio content, (ii) playback timing information associated with the audio content, wherein the playback timing information is generated by the first zone player, and (iii) clock time information for the first zone player, and wherein the generated playback timing information and the clock time information are transmitted from the first zone player to the second zone player;

and

wherein the first zone player playing back audio in synchrony comprises, for each frame of the audio content, the first zone player playing back the frame when the device clock of the first zone player is the same as the playback time for the frame.

11. A system comprising:

a plurality of zone players that are communicatively coupled via at least a local area network (LAN) with a plurality of controllers, wherein;

each of the plurality of controllers is configured to provide control information to any one of the plurality of zone players via the LAN; and

each of the plurality of zone players is configured to (a) receive control information from any one of the plurality of controllers via the LAN, wherein the received control information comprises a direction for the zone player to enter into a synchrony group with at least one other zone player of the plurality of zone players, (b) in response to the direction, enter into the synchrony group with the at least one other zone player of the plurality of zone players, wherein in the synchrony group, the zone player and the at least one other zone player are configured to play back audio in synchrony based at least in part on (b-i) audio content, (b-ii) playback timing information associated with the audio content, wherein the playback timing information is generated by and transmitted from one of the zone player or the at least one other zone player to the other of the zone player or the at least one other zone player and (b-iii) clock time information for the one of the zone player or the at least one other zone player, wherein the clock time information is generated by and transmitted from the one of the zone player or the at least one other zone player to the other of the zone player or the at least one other zone player, wherein the zone players in the synchrony group remain independently clocked while playing back audio in synchrony, and (c) transmit status information to at least one of the plurality of controllers via the LAN, wherein the status information comprises an indication of a status of the synchrony group.

12. The system of claim 11, wherein each of the plurality of zone players is configured to transmit the status information while it is configured to operate as a master device of the synchrony group.

13. The system of claim 11, wherein the status information further comprises one or both of (a) an identification of a track currently being played by the synchrony group and (b) an identification of tracks scheduled to be played by the synchrony group.

14. The system of claim 11, wherein the status information further comprises one or both of (a) an identification of a zone player of the plurality of zone players that is operating as a master device of the synchrony group and (b) an identification of at least one zone player of the plurality of zone players that is operating as a slave device of the synchrony group.

15. The system of claim 11, wherein a device clock of a first zone player is configured to generate clock time information for the first zone player, and wherein a device clock of a second zone player is configured to generate clock time information for the second zone player, and wherein the device clock of the first zone player operates independently from the device clock of the second zone player.

16. The system of claim 11, wherein the plurality of zone players comprises a first zone player and a second zone player, wherein the first zone player is a master zone player of the synchrony group, wherein the audio content comprises a plurality of frames, wherein the playback timing information associated with the audio content comprises a playback time for each frame of the audio content, and wherein the first zone player is configured to play back audio in synchrony with the second zone player based at least in part on (i) the audio content, (ii) playback timing information associated with the audio content, wherein the playback timing information is generated by the first zone player, and (iii) clock time information for the first zone player generated by a device clock of the first zone player, and wherein the generated playback timing information and the clock time information are transmitted from the first zone player to the second zone player;

and

wherein the first zone player playing back audio in synchrony comprises, for each frame of the audio content, the first zone player playing back the frame when the first zone player'"'"'s device clock is the same as the playback time for the frame; and

wherein the second zone player comprises a device clock, and wherein the second zone player playing back audio in synchrony comprises determining a time differential between the first zone player'"'"'s device clock and the second zone player'"'"'s device clock, and for each frame of the audio content, (i) determining a playout time for the frame based on (i-a) the playback timing information received from the first zone player and (i-b) the determined time differential, and (ii) playing the frame at the determined playout time.

17. A first zone player comprising:

a network interface configured to interface the first zone player with at least a local area network (LAN);

a device clock configured to generate clock time information for the first zone player;

one or more processors; and

a tangible, non-transitory computer-readable memory having instructions stored thereon that, when executed by the one or more processors, cause the first zone player to;

receive control information from any one of a plurality of controllers over the LAN via the network interface, wherein the received control information comprises a direction for the first zone player to enter into a synchrony group with at least a second zone player;

in response to the direction, enter into the synchrony group with the second zone player, wherein in the synchrony group, the first and second zone players are configured to playback audio in synchrony based at least in part on (i) audio content, (ii) playback timing information associated with the audio content, wherein the playback timing information 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

transmit status information to at least one of the plurality of controllers over the LAN via the network interface, wherein the status information comprises an indication of a status of the synchrony group.

18. The first zone player of claim 17, wherein the status information further comprises one or both of (a) an identification of a track currently being played by the synchrony group and (b) an identification of tracks scheduled to be played by the synchrony group.

19. The first zone player of claim 18 wherein the identification of the track currently being played by the synchrony group comprises a name of the track currently being played by the synchrony group.

20. The first zone player of claim 18, wherein the identification of the tracks scheduled to be played by the synchrony group comprises a list of names of tracks scheduled to be played by the synchrony group.

21. The first zone player of claim 17, wherein the status information further comprises one or both of (a) an identification of a zone player that is operating as a master device of the synchrony group and (b) an identification of at least one zone player that is operating as a slave device of the synchrony group.

22. The first zone player of claim 17, wherein the first zone player comprises a master device of the synchrony group.

23. The first zone player of claim 17, wherein the tangible computer-readable memory further has instructions stored thereon that, when executed by the one or more processors, cause the first zone player to determine whether the first zone player is operating as a master device of the synchrony group, and wherein the instructions that cause the first zone player to transmit status information to the at least one of the plurality of controllers comprise instructions that cause the first zone player to transmit status information to the at least one of the plurality of controllers only while the first zone player is operating as the master device of the synchrony group.

24. The first zone player of claim 23, wherein the tangible computer-readable memory further has instructions stored thereon that, when executed by the one or more processors, cause the first zone player to:

receive audio content via the network interface; and

while the first zone player is operating as the master device of the synchrony group, transmit the received audio content, via the network interface, to at least one zone player that is operating as a slave device of the synchrony group.

25. The first zone player of claim 17, wherein the device clock of the first zone player operates independently of a device clock of the second zone player.

26. The first zone player of claim 17, wherein the first zone player is a master zone player of the synchrony group, wherein the audio content comprises a plurality of frames, wherein the playback timing information associated with the audio content comprises a playback time for each frame of the audio content, and wherein the first zone player is configured to play back audio in synchrony with the second zone player based at least in part on (i) the audio content, (ii) playback timing information associated with the audio content, wherein the playback timing information is generated by the first zone player, and (iii) clock time information for the first zone player, and wherein the generated playback timing information and the clock time information are transmitted from the first zone player to the second zone player;

and

wherein the first zone player playing back audio in synchrony comprises, for each frame of the audio content, the first zone player playing back the frame when the device clock of the first zone player is the same as the playback time for the frame.