Audio group identification for conferencing

1. A system comprising:

one or more processors; and

one or more non-transitory computer-readable media storing computer-executable instructions that, when executed by the one or more processors, cause the one or more processors to perform operations comprising:

joining a conference call using a network interface;

accessing an audio signal that has been captured using a microphone;

receiving, using the network interface, a control channel identifier;

based at least in part on the control channel identifier, detecting a first control signal in a control channel of the audio signal that is identified by the control channel identifier;

responsive to detecting the first control signal, invoking modification of an audio path of the conference call; and

playing a second control signal using a speaker.

2. The system of claim 1 , wherein the first control signal was played using a speaker of a computing device that has also joined the conference call.

3. The system of claim 1 , further comprising:

invoking the modification of the audio path of the conference call by transmitting a message to a bridge server of the conference call, the message identifying a group of two or more computing devices that have joined the conference call as sharing an audio environment.

4. The system of claim 3 , further comprising:

responsive to receiving the message, disabling, by the bridge server, a mixing of audio signals received from members of the group into audio signals that the bridge server transmits to members of the group.

5. The system of claim 1 , further comprising:

invoking the modification of the audio path of the conference call by reducing a gain of the speaker.

6. The system of claim 1 , further comprising:

invoking the modification of the audio path of the conference call by reducing a gain of the microphone.

7. The system of claim 1 , wherein the second control signal is on a same channel as the first control signal.

8. The system of claim 1 , wherein the second control signal is on a different control channel than the first control signal.

9. The system of claim 8 , wherein the first control signal indicates a presence of a primary device of an audio environment associated with the conference call, and the second control signal indicates a presence of a secondary device of the audio environment associated with the conference call.

10. The system of claim 9 , further comprising:

designating the secondary device as a successor to the primary device;

detecting a prolonged absence of the first control signal; and

responsive to detecting the prolonged absence, stop playing the second control signal and start playing a control signal on a same control channel as the first control signal.

11. The system of claim 8 , wherein the second control signal indicates a presence of a primary device of an audio environment associated with the conference call, and the first control signal indicates a presence of a secondary device of the audio environment associated with the conference call.

12. The system of claim 1 , wherein the audio signal is a first audio signal, and the computer-readable media is further configured to cause the one or more processors to perform acts comprising:

accessing a second audio signal received via the network interface from a bridge server of the conference call;

detecting a second control channel identifier in the second audio signal; and

based at least in part on the second control channel identifier, detecting the first control signal in a control channel of the first audio signal that is identified by the second control channel identifier.

13. The system of claim 12 , further comprising:

applying filter to remove a signal encoding the second control channel identifier from the second audio signal to obtain a clean audio signal; and

playing an audio signal based on the clean audio signal using the speaker.

14. The system of claim 1 , further comprising:

determining a cross correlation between an audio signal captured using the microphone and an audio signal received via the network interface from a bridge server of the conference call;

based on the cross correlation, detecting an audio feedback loop in the conference call; and

responsive to detecting the audio feedback loop, reducing a volume parameter of a speaker.

15. A method comprising:

joining a conference call using a network interface;

accessing a first audio signal that has been captured using a microphone;

accessing a second audio signal received via the network interface from a bridge server of the conference call;

detecting a control channel identifier in the second the audio signal;

based at least in part on the control channel identifier, detecting a first control signal in a control channel of the first audio signal that is identified by the control channel identifier;

responsive to detection of the first control signal, invoking modification of an audio path of the conference call; and

playing a second control signal using a speaker.

16. The method of claim 15 , wherein the first control signal was played using a speaker of a computing device that has also joined the conference call.

17. The method of claim 15 , wherein the modification of the audio path of the conference call comprises:

transmitting a message to a bridge server of the conference call that identifies a group of two or more computing devices that have joined the conference call as sharing an audio environment.

18. The method of claim 15 , wherein invoking the modification of the audio path of the conference call comprises muting the speaker.

19. The method of claim 15 , wherein invoking the modification of the audio path of the conference call comprises muting the microphone.

20. The method of claim 15 , wherein the second control signal is on a same control channel as the first control signal.

21. The method of claim 15 , wherein the second control signal is on a different control channel than the first control signal.

22. The method of claim 21 , wherein the first control signal indicates a presence of a primary device of an audio environment associated with the conference call, and the second control signal indicates a presence of a secondary device of the audio environment associated with the conference call.

23. The method of claim 22 , further comprising:

designating the secondary device as a successor to the primary device;

detecting a prolonged absence of the first control signal; and

responsive to detection of the prolonged absence, stop playing the second control signal and start playing a control signal on a same control channel as the first control signal.

24. The method of claim 21 , wherein the second control signal indicates a presence of a primary device of an audio environment associated with the conference call, and the first control signal indicates a presence of a secondary device of the audio environment associated with the conference call.

25. The method of claim 15 further comprising:

applying a filter to remove a signal encoding the control channel identifier from the second audio signal to obtain a clean audio signal; and

playing an audio signal based on the clean audio signal using a speaker.

26. The method of claim 15 , further comprising:

receiving, using the network interface, a control channel identifier; and

based on the control channel identifier, detecting the first control signal in a control channel of the audio signal that is identified by the control channel identifier.

27. The method of claim 15 , further comprising:

determining a cross correlation between an audio signal captured using the microphone and an audio signal received via the network interface from a bridge server of the conference call;

based on the cross correlation, detecting an audio feedback loop in the conference call; and

responsive to detection of the audio feedback loop, reducing a volume parameter of a speaker.

28. A non-transitory computer-readable storage media storing computer-executable instructions that, when executed by a processor, cause the processor to perform operations comprising:

joining a conference call using a network interface;

accessing an audio signal that has been captured using a microphone;

detecting a first control signal in the audio signal, wherein the first control signal indicates a presence of a primary device of an audio environment associated with the conference call;

responsive to detection of the first control signal, invoking modification of an audio path of the conference call;

playing a second control signal using a speaker, wherein the second control signal is on a different control channel than the first control signal and indicates a presence of a secondary device of the audio environment associated with the conference call;

detecting a prolonged absence of the first control signal; and

based at least in part on the prolonged absence, stop playing the second control signal and start playing a control signal on a same control channel as the first control signal.

29. The non-transitory computer-readable storage media of claim 28 , wherein the first control signal was played using a speaker of a computing device that has also joined the conference call.

30. The non-transitory computer-readable storage media of claim 28 , wherein invoking the modification of the audio path of the conference call comprises:

transmitting a message to a bridge server of the conference call that identifies a group of two or more computing devices that have joined the conference call as sharing an audio environment.

31. The non-transitory computer-readable storage media of claim 28 , wherein invoking the modification of the audio path of the conference call comprises muting the speaker.

32. The non-transitory computer-readable storage media of claim 28 , wherein invoking modification of the audio path of the conference call comprises muting the microphone.

33. The non-transitory computer-readable storage media of claim 28 , wherein the second control signal is on a same control channel as the first control signal.

34. The non-transitory computer-readable storage media of claim 28 , wherein the second control indicates a presence of a primary device of an audio environment associated with the conference call, and the first control signal indicates a presence of a secondary device of the audio environment associated with the conference call.

35. The non-transitory computer-readable storage media of claim 28 , wherein the audio signal is a first audio signal, the operations further comprising:

accessing a second audio signal received via the network interface from a bridge server of the conference call;

detecting a control channel identifier in the second audio signal; and

based at least in part on the control channel identifier, detecting the first control signal in a control channel of the first audio signal that is identified by the control channel identifier.

36. The non-transitory computer-readable storage media of claim 35 , storing computer-executable instructions that, when executed by a processor, cause the processor to perform operations comprising:

applying a filter to remove a signal encoding the control channel identifier from the second audio signal to obtain a clean audio signal; and

playing an audio signal based on the clean audio signal using a speaker.

37. The non-transitory computer-readable storage media of claim 28 , storing computer-executable instructions that, when executed by a processor, cause the processor to perform operations comprising:

receiving, using the network interface, a control channel identifier; and

based at least in part on the control channel identifier, detecting the first control signal in a control channel of the audio signal that is identified by the control channel identifier.

38. The non-transitory computer-readable storage media of claim 28 , storing computer-executable instructions that, when executed by a processor, cause the processor to perform operations comprising:

determining a cross correlation between an audio signal captured using the microphone and an audio signal received via the network interface from a bridge server of the conference call;

based on the cross correlation, detecting an audio feedback loop in the conference call; and

responsive detection of the audio feedback loop, reducing a volume parameter of a speaker.