Dual streaming with exchange of FEC streams by audio sinks

• US 8,194,878 B2
• Filed: 09/08/2011
• Issued: 06/05/2012
• Est. Priority Date: 03/24/2008
• Status: Active Grant

• Current Assignee: Avago Technologies International Sales Pte Limited (Broadcom, Inc.)
• Original Assignee: Broadcom Corporation (Broadcom, Inc.)
• Inventors: Pilati, Laurent, Jougit, Mickael
• Primary Examiner(s): Nguyen, Dao H
• Application Number:
  US13/227,710
• Publication Number:
  US 20110320214A1
• Time in Patent Office: 271 Days
• Field of Search: 381/17, 381/18, 381/22, 381/26, 381/79, 381/80, 381/309, 381/311, 379/67.1, 379/78, 379/353, 379/357.01, 455/575.2
• US Class Current: 381/79
• CPC Class Codes: H04L 1/004 by using forward error control H04L1/0618 takes precedence; coding, decoding or code conversion, for error detection or correction H03M13/00
• CPC Class Codes: H04L 1/0083 Formatting with frames or packets; Protocol or part of protocol for error control
• CPC Class Codes: H04L 1/02 by diversity reception
• CPC Class Codes: H04L 2001/0092 Error control systems characterised by the topology of the transmission link
• CPC Class Codes: H04L 25/14 Channel dividing arrangements , i.e. in which a single bit stream is divided between several baseband channels and reassembled at the receiver
• CPC Class Codes: H04L 5/0001 Arrangements for dividing the transmission path duplexing H04L5/14; multiplexing of different sources on one path H04J

Abstract

A system and method is described herein in which an audio source wirelessly transmits audio content to a first audio sink over one wireless link and to a second audio sink over another wireless link. The two audio sinks also exchange forward error correction (FEC) streams over a link between the two audio sinks, wherein the FEC streams are generated by FEC encoding the audio content received from the audio source. The audio sinks advantageously use the exchanged FEC information to synchronize the playback of the audio content as well as to improve the robustness of the wireless links with the audio source in a manner that does not consume additional bandwidth on those links.

Claims

1. A method for processing audio content for playback in a first audio sink, comprising:

receiving one or more audio packets from an audio source over a first wireless link;

receiving a forward error correction (FEC) packet from a second audio sink, wherein the second audio sink generated the received FEC packet by FEC encoding a plurality of audio packets received from the audio source over a second wireless link;

recovering a lost audio packet based on the one or more received audio packets and the received FEC packet; and

decoding the one or more received audio packets and the recovered audio packet for playback.

2. The method of claim 1, wherein recovering a lost audio packet based on the one or more received audio packets and the received FEC packet comprises:

performing an exclusive-or operation based on the one or more received audio packets and the received FEC packet.

3. The method of claim 1, further comprising:

receiving a plurality of audio packets from the audio source over the first wireless link;

performing FEC encoding on the received plurality of audio packets to generate an FEC packet; and

transmitting the generated FEC packet to the second audio sink.

4. The method of claim 3, wherein performing FEC encoding on the received plurality of audio packets to generate a second FEC packet comprises:

performing an exclusive-or operation based on two or more packets within the received plurality of audio packets.

5. The method of claim 1, further comprising:

analyzing the received FEC packet to estimate a buffering drift associated with audio content played back by the first audio sink and the second audio sink; and

synchronizing the playback of audio content by the first audio sink based on the analysis.

6. The method of claim 5, wherein analyzing the received FEC packet to estimate a buffering drift associated with audio content played back by the first audio sink and the second audio sink comprises:

analyzing a time stamp associated with the received FEC packet.

7. The method of claim 1, wherein at least one of the first wireless link, and the second wireless link comprises a Bluetooth™

wireless link.

8. The method of claim 1, wherein at least one of the first wireless link and the second wireless link comprises an IEEE 802.11 wireless link.

9. An audio sink, comprising:

an interface configured to receive one or more audio packets from an audio source over a first wireless link and to receive a forward error correction (FEC) packet from an other audio sink, wherein the other audio sink generated the received FEC packet by encoding a plurality of audio packets received from the audio source over a second wireless link;

recovery logic communicatively connected to the interface, the recovery logic configured to recover a lost audio packet based on the one or more received audio packets and the received FEC packet; and

audio decoding logic communicatively connected to the recovery logic, the audio decoding logic configured to decode the one or more received audio packets and the recovered audio packet for playback.

10. The audio sink of claim 9, wherein the recovery logic is configured to recover the lost audio packet by performing an exclusive-or operation based on the one or more received audio packets and the received FEC packet.

11. The audio sink of claim 9, wherein the interface is further configured to receive a plurality of audio packets from the audio source over the first wireless link, wherein the recovery logic is further configured to perform FEC encoding on the received plurality of audio packets to generate an FEC packet, and wherein the interface is still further configured to transmit the generated FEC packet to the other audio sink.

12. The audio sink of claim 9, wherein the recovery logic is configured to perform FEC encoding on the received plurality of audio packets by performing an exclusive-or operation based on two or more packets within the received plurality of audio packets.

13. The audio sink of claim 9, further comprising:

synchronization logic communicatively connected to the recovery logic and the decoding logic, the synchronization logic configured to analyze the received FEC packet to estimate a buffering drift associated with audio content played back by the audio sink and the other audio sink and to synchronize the playback of audio content by the audio sink based on the analysis.

14. The audio sink of claim 13, wherein the synchronization logic is configured to analyze a time stamp associated with the received FEC packet to estimate the buffering drift.

15. A system, comprising:

a first audio sink configured to receive a plurality of audio packets from an audio source over a first wireless link, to perform forward error correction (FEC) encoding on the plurality of audio packets to generate an FEC packet, to transmit the FEC packet, and to decode the plurality of audio packets for playback; and

a second audio sink configured to receive one or more packets from the audio source over a second wireless link, to receive the FEC packet from the first audio sink, to recover a lost audio packet based on the one or more packets received from the audio source and the FEC packet, and to decode the one or more audio packets received from the audio source and the recovered audio packet for playback.

16. The system of claim 15, wherein the first audio sink is configured to perform FEC encoding on the plurality of audio packets by performing an exclusive-or operation based on two or more packets within the plurality of audio packets.

17. The system of claim 15, wherein the second audio sink is configured to recover the lost audio packet by performing an exclusive-or operation based on the one or more audio packets received from the audio source and the FEC packet.

18. The system of claim 15, wherein the second audio sink is configured to analyze the FEC packet to estimate a buffering drift associated with audio content played back by the first audio sink and the second audio sink and to synchronize the playback of audio content based on the analysis.

19. The system of claim 18, wherein the second audio sink is configured to analyze a time stamp associated with the FEC packet to estimate the buffering drift.

20. The system of claim 15, wherein at least one of the first wireless link and the second wireless link is a Bluetooth™

wireless link.

21. The system of claim 15, wherein at least one of the first wireless link and the second wireless link is an IEEE 802.11 wireless link.