System for time synchronization of audio devices

• US 9,979,998 B1
• Filed: 05/02/2017
• Issued: 05/22/2018
• Est. Priority Date: 05/02/2017
• Status: Active Grant

• Current Assignee: Amazon Technologies, Inc. (Amazon.com, Inc.)
• Original Assignee: Amazon Technologies, Inc. (Amazon.com, Inc.)
• Inventors: Pogue, Michael Alan, Haight, Kyle Gordon
• Primary Examiner(s): Phu, Phuong
• Application Number:
  US15/584,873
• Time in Patent Office: 385 Days
• Field of Search: 375356, 375354, 375357, 375358
• CPC Class Codes: G06F 3/165 Management of the audio stream, e.g. setting of volume, audio stream path
• CPC Class Codes: G11B 27/10 Indexing; Addressing; Timing or synchronising; Measuring tape travel
• CPC Class Codes: H04J 3/0664 unidirectional timestamps
• CPC Class Codes: H04J 3/0667 Bidirectional timestamps, e.g. NTP or PTP for compensation of clock drift and for compensation of propagation delays arrangements for monitoring round trip delays in packet switching networks H04L43/0864
• 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 21/43637 involving a wireless protocol, e.g. Bluetooth, RF or wireless LAN [IEEE 802.11] arrangements for wireless networking or broadcasting of information in indoor or near-field type systems H04B10/114
• CPC Class Codes: H04N 21/8106 involving special audio data, e.g. different tracks for different languages
• CPC Class Codes: H04N 21/8547 involving timestamps for synchronizing content

Abstract

Described are techniques for synchronizing multiple devices within a group to enable performance of a synchronized action through the exchange of time data. A first device provides a timestamp or other time data to multiple other devices via a multicast transmission. Each of the other devices determines a time at which the timestamp was received and exchanges this data with one another. Based on the determined times, the other devices may be synchronized relative to a selected synchronization master device. One of the other devices may then determine a from the first device, and determine the time at which the timestamp from the first device was received, enabling the first device to be synchronized with the synchronization master device. Devices that are unable to receive multicast transmissions from the first device may exchange timestamps with the first device via an access point.

Claims

1. A system comprising:

a first audio device;

a second audio device;

a third audio device, wherein the first audio device is configured to provide audio data to the second audio device and the third audio device via multicast transmissions;

one or more memories storing computer-executable instructions; and

one or more hardware processors to execute the computer-executable instructions to;

send, by the first audio device, first time data to the second audio device and the third audio device via a multicast transmission;

determine, by the second audio device, second time data indicative of a time at which the first time data was received by the second audio device;

determine, by the third audio device, third time data indicative of a time at which the first time data was received by the third audio device;

send, by the third audio device, the first time data and the third time data to the second audio device;

determine, by the second audio device, that the first time data generated by the first audio device corresponds to the first time data received from the third audio device;

determine, by the second audio device, first offset data indicative of a difference between the second time data and the third time data;

send, by the second audio device, a first request for time data to the first audio device;

determine, by the second audio device, fourth time data indicative of a time at which the first request was sent by the second audio device;

determine, by the first audio device, fifth time data indicative of a time at which the first request was received;

send, by the first audio device, the fifth time data to the second audio device;

determine, by the second audio device, sixth time data indicative of a time at which the fifth time data was received;

determine, by the second audio device, second offset data indicative of a difference between the fourth time data and the fifth time data and a difference between the fifth time data and the sixth time data;

determine, based on the first offset data and the second offset data, third offset data indicative of a difference between the first time data and the third time data; and

output audio using the first audio device, the second audio device, and the third audio device, wherein a first timing of audio output of the third audio device is based on the third offset data and a second timing of audio output of the second audio device is based on the second offset data.

2. The system of claim 1, further comprising computer-executable instructions to:

send, by the second audio device, the first time data and the second time data to the third audio device;

wherein the first offset data is determined by each of the second audio device and the third audio device.

3. The system of claim 1, further comprising computer-executable instructions to:

determine, by the third audio device, a plurality of the first time data and a plurality of the third time data over a period of time;

subsequent to the period of time, provide the plurality of the first time data and the plurality of the third time data from the third audio device to the second audio device; and

provide an indication of the third offset data from the second audio device to the third audio device.

4. The system of claim 1, further comprising:

a fourth audio device;

an access point in communication with the first audio device and the fourth audio device; and

computer-executable instructions to;

send, by the fourth audio device, a second request for time data to the first audio device;

determine, by the fourth audio device, seventh time data indicative of a time at which the second request was sent;

determine, by the first audio device, eighth time data indicative of a time at which the first audio device received the second request;

send, by the first audio device, the eighth time data to the fourth audio device;

determine, by the fourth audio device, ninth time data indicative of a time that the eighth time data was received by the fourth audio device;

determine, using the fourth audio device, fourth offset data indicative of a difference between the seventh time data and the eighth time data and a difference between the eighth time data and the ninth time data; and

output the audio using the fourth audio device, wherein a third timing of audio output using the fourth audio device is based on the fourth offset data.

5. A method comprising:

determining first time data indicative of a time at which an event associated with a first device is detected by a second device;

determining second time data indicative of a time at which the event is detected by a third device;

determining first offset data based on a difference between the first time data and the second time data;

sending, by the second device, a request to the first device;

determining, by the second device, third time data indicative of a time at which the request was sent to the first device;

sending, by the first device to the second device, fourth time data indicative of a time at which the request was received by the first device;

determining fifth time data indicative of a time at which the second device received the fourth time data;

determining second offset data based on one or more differences between the third time data, the fourth time data, and the fifth time data; and

causing the first device, the second device, and the third device to perform a synchronized action, wherein a first timing associated with the second device is based on the first offset data and a second timing associated with the third device is based on the first offset data and the second offset data.

6. The method of claim 5, wherein the event includes receiving, by the second device and the third device, sixth time data, from the first device, via a multicast transmission, wherein the sixth time data is indicative of a time at which the sixth time data was sent, and wherein the determining of the first offset data further includes:

determining that the time indicated by the sixth time data received by the first device corresponds to the time indicated by sixth time data received by the second device; and

based on the correspondence between the sixth time data received by the first device and the sixth time data received by the second device, determining that the first time data is associated with the second time data.

7. The method of claim 5, further comprising sending one or more of the fourth time data or the sixth time data to the first device and the third device, wherein the first offset data is further determined based in part on the one or more of the fourth time data or the sixth time data.

8. The method of claim 5, further comprising:

sending the first time data to the third device; and

sending the second time data to the second device;

wherein the first offset data is determined by each of the first device and the second device.

9. The method of claim 5, further comprising:

sending, by the second device, the second time data to the third device, wherein the second time data includes a first timestamp indicative of a time at which the first time data was transmitted by the first device and a second timestamp indicative of a time at which the first time data was received by the second device; and

sending, by the third device, the third time data to the second device, wherein the third time data includes the first timestamp and a third timestamp indicative of a time at which the first time data was received by the third device;

wherein the determining the first offset data includes;

determining that the first timestamp received by the second device corresponds to the first timestamp received by the third device; and

based on the correspondence between the first timestamp received by the second device and the first timestamp received by the third device, determining a difference between the second timestamp and the third timestamp.

10. The method of claim 5, further comprising determining a plurality of third time data and a plurality of fifth time data;

and

sending, by the first device, the plurality of the third time data and the plurality of the fifth time data to one or more of the second device or the third device in a single transmission.

11. The method of claim 5, further comprising:

sending, by the first device, a request for time data to a fourth device via an access point in communication with the first device and the fourth device;

determining seventh time data indicative of a time at which the request was sent;

determining eighth time data indicative of a time at which the request was received by the fourth device;

sending, by the fourth device, the eighth time data to the first device;

determining ninth time data indicative of a time at which the eighth time data was received by the first device;

determining third offset data based on one or more differences between the seventh time data, the eighth time data, and the ninth time data; and

performing the synchronized action using the fourth device, wherein a third timing associated with the fourth device is based in part on the third offset data.

12. The method of claim 5, further comprising:

sending, by a fourth device, a request for time data to the first device via an access point in communication with the first device and the fourth device;

determining seventh time data indicative of a time at which the request was sent;

determining eighth time data indicative of a time at which the request was received by the first device;

sending, by the first device, the eighth time data to the fourth device;

determining ninth time data indicative of a time at which the eighth time data was received by the fourth device;

determining third offset data based on one or more differences between the seventh time data, the eighth time data, and the ninth time data; and

performing the synchronized action using the fourth device, wherein a third timing associated with the fourth device is based in part on the third offset data.

13. A system comprising:

an access point;

a first device in communication with the access point;

a second device in communication with the access point;

a third device in communication with the second device;

one or more memories storing computer-executable instructions; and

one or more hardware processors to execute the computer-executable instructions to;

send, by the first device, a request for time data to the second device via the access point;

determine first time data indicative of a time at which the request was sent by the first device;

determine second time data indicative of a time at which the request was received by the second device;

send, by the second device, the second time data to the first device;

determine third time data indicative of a time at which the second time data was received by the first device;

send, by the second device, fourth time data to the third device;

determine fifth time data indicative of a time at which the fourth time data was received by the third device;

determine first offset data based on one or more differences between the first time data, the second time data, and the third time data;

determine second offset data based in part on a difference between the fourth time data and the fifth time data;

based on the first offset data and the second offset data, determine a first time associated with performance of a synchronized action by the first device relative to the second device and a second time associated with performance of the synchronized action by the third device relative to the second device; and

perform the synchronized action using the first device, the second device, and the third device.

14. The system of claim 13, further comprising a fourth device in communication with the second device, wherein the computer-executable instructions to send the first time data include computer-executable instructions to:

send, by the second device, the fourth time data to the third device and the fourth device via a multicast transmission;

determine sixth time data indicative of a time at which the fourth time data was received by the fourth device;

determine third offset data based on a difference between the fifth time data and the sixth time data; and

determine, based in part on the third offset data, a third time associated with performance of the synchronized action by the fourth device relative to the second device.

15. The system of claim 14, further comprising computer-executable instructions to:

send, by the third device, a request for time data to the second device;

determine seventh time data indicative of a time at which the request was sent;

determine eighth time data indicative of a time at which the request was received by the second device;

send, by the second device, the eighth time data to the third device;

determine ninth time data indicative of a time that the eighth time data was received by the third device; and

determine fourth offset data based on one or more differences between the seventh time data, the eighth time data, and the ninth time data;

wherein the third time is further determined based in part on the fourth offset data.

16. The system of claim 15, further comprising computer-executable instructions to:

determine, by the third device, a plurality of fifth time data;

send a plurality of fourth time data and the plurality of fifth time data to the fourth device in a single transmission, wherein the third offset data is determined by the fourth device; and

send an indication of the third offset data from the fourth device to the third device.

17. The system of claim 14, further comprising computer-executable instructions to:

send, by the third device, seventh time data to the second device and the fourth device via a multicast transmission, wherein the ninth time data includes a first timestamp indicative of a time at which the seventh time data was transmitted by the third device; and

send, by the fourth device, eighth time data to the second device and the third device via a multicast transmission, wherein the eighth time data includes a second timestamp indicative of a time at which the eighth time data was transmitted by the fourth device;

wherein the first time and the second time are further determined based in part on one or more of the seventh time data or the eighth time data.

18. The system of claim 17, further comprising computer-executable instructions to:

send, by the fourth device, the sixth time data to the third device;

wherein the second time is further determined based in part on the seventh time data and the third time is further determined based in part on the eighth time data.

19. The system of claim 14, further comprising computer-executable instructions to:

send, by the third device, the fourth time data and the fifth time data to the fourth device, wherein the fourth time data includes a first timestamp indicative of a time at which the fourth time data was transmitted by the second device and the fifth time data includes a second timestamp indicative of the time at which the fourth time data was received by the third device;

send, by the fourth device, the fourth time data and the sixth time data to the third device, wherein the sixth time data includes a third timestamp indicative of the time at which the fourth time data was received by the fourth device;

wherein the determining the third offset data includes;

determining that the first timestamp received by the third device corresponds to the first timestamp received by the fourth device; and

determining a difference between the second timestamp and the third timestamp.

20. The system of claim 13, further comprising:

a fourth device in communication with the first device; and

computer-executable instructions to;

send, by the first device, sixth time data to the fourth device;

determine seventh time data indicative of a time at which the sixth time data was received by the fourth device;

send, by the fourth device, the seventh time data to the first device;

determine, by the first device, eighth time data indicative of a time at which the seventh time data was received by the first device;

determine third offset data based on a difference between the sixth time data and the seventh time data and a difference between the seventh time data and the eighth time data;

based on the third offset data, determine a third time associated with output of the content by the fourth device relative to the first device; and

perform the synchronized action using the fourth device.