Wireless audio synchronization using a spread code

Patent metadata

Field	Value
Publication number	US-10931909-B2
Application number	US-201816133813-A
Country	US
Kind code	B2
Filing date	Sep 18, 2018
Priority date	Sep 18, 2018
Publication date	Feb 23, 2021
Grant date	Feb 23, 2021

Abstract

Disclosed herein are system, apparatus, article of manufacture, method and/or computer program product embodiments, and/or combinations and sub-combinations thereof, for synchronizing playback of audiovisual content among multiple speakers. In some embodiments, a first smart speaker receives a spread spectrum signal from a second smart speaker over an audio data channel. The first smart speaker despreads the spread spectrum signal based on a spreading code. The first smart speaker determines a time of receipt of the spread spectrum signal based on the despreading. The first smart speaker receives a time of transmission of the spread spectrum signal. The first smart speaker then calculates a playback delay based on the time of receipt and the time of transmission. Then the first smart speaker controls the playback of the audiovisual content based on the playback delay.

First claim

What is claimed is:

1. A computer implemented method for synchronizing playback of audiovisual content at a first electronic device and a second electronic device, comprising:
receiving, by a microphone at the first electronic device, a spread spectrum signal played back auditorily by the second electronic device;
despreading, by at least one processor at the first electronic device, the spread spectrum signal based on a spreading code;
determining, by the at least one processor at the first electronic device, a time of receipt of the spread spectrum signal based on the despreading;
receiving, by the at least one processor at the first electronic device, a time of transmission of the spread spectrum signal, wherein the time of transmission of the spread spectrum signal indicates when the spread spectrum signal was played back by the second electronic device;
calculating, by the at least one processor at the first electronic device, a playback delay of the second electronic device based on the time of receipt of the spread spectrum signal and the time of transmission of the spread spectrum signal, wherein the playback delay comprises a time delay between receiving the audiovisual content at the second electronic device and the audiovisual content being played back auditorily by the second electronic device; and
controlling, by the at least one processor, the playback of the audiovisual content based on the playback delay.

2. The method of claim 1 , wherein the receiving the time of transmission of the spread spectrum signal further comprises:
receiving, by the at least one processor at the first electronic device, the time of transmission of the spread spectrum signal using a wireless communication protocol.

3. The method of claim 1 , wherein the controlling further comprises:
controlling, by the at least one processor at the first electronic device, the playback of the audiovisual content based on the playback delay and a second playback delay associated with the first electronic device.

4. The method of claim 1 , wherein the despreading further comprises:
despreading, by the at least one processor at the first electronic device, the spread spectrum signal based on a reference point associated with the spreading code.

5. The method of claim 4 , wherein the despreading further comprises:
selecting, by the at least one processor at the first electronic device, a sliding window into the spreading code based on the reference point; and
despreading, by the at least one processor at the first electronic device, the spread spectrum signal based on the sliding window.

6. The method of claim 1 , wherein the receiving the spread spectrum signal further comprises:
receiving, by the microphone at the first electronic device, the spread spectrum signal played back auditorily by the second electronic device in response to a boot up of the second electronic device, or in response to detecting the playback of the audiovisual content at the first electronic device is not synchronized with the playback of the audiovisual content at the second electronic device.

7. The method of claim 1 , wherein the controlling further comprises:
changing, by the at least one processor at the first electronic device, an amount of the audiovisual content to buffer based on the playback delay.

8. The method of claim 1 , wherein the controlling further comprises:
changing, by the at least one processor at the first electronic device, a playback offset for the audiovisual content based on the playback delay.

9. The method of claim 1 , further comprising:
performing, by the at least one processor at the first electronic device, echo cancellation on a voice input based on the playback delay.

10. The method of claim 1 , wherein the first electronic device comprises a first smart speaker and the second electronic device comprises a second smart speaker.

11. The method of claim 1 , wherein the playback delay for the second electronic device comprises an airtime delay for the second electronic device.

12. A system, comprising:
a memory; and
at least one processor coupled to the memory and configured to:
receive, by a microphone at the system, a spread spectrum signal played back auditorily by an electronic device;
despread the spread spectrum signal based on a spreading code;
determine a time of receipt of the spread spectrum signal based on the despreading;
receive a time of transmission of the spread spectrum signal, wherein the time of transmission of the spread spectrum signal indicates when the spread spectrum signal was played back by the electronic device;
calculate a playback delay based on the time of receipt of the spread spectrum signal and the time of transmission of the spread spectrum signal, wherein the playback delay comprises a time delay between receiving audiovisual content at the electronic device and the audiovisual content being played back auditorily by the electronic device; and
control the playback of the audiovisual content based on the playback delay.

13. The system of claim 12 , wherein to receive the time of transmission of the spread spectrum signal, the at least one processor is further configured to:
receive the time of transmission of the spread spectrum signal using a wireless communication protocol.

14. The system of claim 12 , wherein to control the playback of the audiovisual content, the at least one processor is further configured to:
control the playback of the audiovisual content based on the playback delay and a second playback delay associated with the system.

15. The system of claim 12 , wherein to despread, the at least one processor is further configured to:
despread the spread spectrum signal based on a reference point associated with the spreading code.

16. The system of claim 12 , wherein to receive the spread spectrum signal, the at least one processor is further configured to:
receive, by the microphone at the system, the spread spectrum signal played back auditorily by the electronic device in response to a boot up of the electronic device, or in response to detecting the playback of the audiovisual content at the system is not synchronized with the playback of the audiovisual content at the electronic device.

17. The system of claim 12 , wherein the at least one processor is further configured to:
perform echo cancellation on a voice input based on the playback delay.

18. A non-transitory computer-readable medium having instructions stored thereon that, when executed by at least one computing device, cause the at least one computing device to perform operations comprising:
receiving, by a microphone at the computing device, a spread spectrum signal played back auditorily by an electronic device;
despreading the spread spectrum signal based on a spreading code;
determining a time of receipt of the spread spectrum signal based on the despreading;
receiving a time of transmission of the spread spectrum signal, wherein the time of transmission of the spread spectrum signal indicates when the spread spectrum signal was played back by the electronic device;
calculating a playback delay based on the time of receipt of the spread spectrum signal and the time of transmission of the spread spectrum signal, wherein the playback delay comprises a time delay between receiving audiovisual content at the electronic device and the audiovisual content being played back auditorily by the electronic device; and
controlling the playback of the audiovisual content based on the playback delay.

19.

Assignees

• Roku Inc

Inventors

• Curtis Robert Caston
• Ely Mark
• Møller Brian Thoft Moth

Classifications

• H04N21/43076

  of the same content streams on multiple devices, e.g. when family members are watching the same movie on different devices · CPC title

• H04N5/607 Primary

  for more than one sound signal, e.g. stereo, multilanguages (H04N5/602 takes precedence) · CPC title

• H04N21/43637

  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 title

• G06F3/167

  Audio in a user interface, e.g. using voice commands for navigating, audio feedback · CPC title

• H04R2420/07

  Applications of wireless loudspeakers or wireless microphones · CPC title