Audio conferencing utilizing packets with unencrypted power level information

• US 8,116,236 B2
• Filed: 01/04/2007
• Issued: 02/14/2012
• Est. Priority Date: 01/04/2007
• Status: Active Grant

• Current Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Original Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Inventors: Baird, Randall B., Surazski, Luke K.
• Primary Examiner(s): Harper, Kevin C
• Assistant Examiner(s): TRAN, THINH D
• Application Number:
  US11/650,592
• Publication Number:
  US 20080165707A1
• Time in Patent Office: 1,867 Days
• Field of Search: None
• US Class Current: 370/260
• CPC Class Codes: H04L 12/1827 Network arrangements for conference optimisation or adaptation
• CPC Class Codes: H04L 65/4038 with floor control
• CPC Class Codes: H04L 65/70 Media network packetisation
• CPC Class Codes: H04L 65/765 intermediate
• CPC Class Codes: H04M 3/56 Arrangements for connecting several subscribers to a common circuit, i.e. affording conference facilities video conference systems H04N7/15
• CPC Class Codes: H04M 3/568 audio processing specific to telephonic conferencing, e.g. spatial distribution, mixing of participants echo suppression in two-way loud-speaking telephone systems H04M9/02; sound field processing per se H04S7/30

Abstract

In one embodiment, a method that includes receiving a plurality of packet streams input from different endpoints, packets of each stream including encrypted and unencrypted portions, the unencrypted portion containing audio power level information. The audio power level information contained in the packets of each of the packet streams is then compared to select N packet streams with loudest audio. The N packet streams are then decrypted to obtain audio content, and the audio content of the N packet streams mixed to produce one or more output packet streams. It is emphasized that this abstract is provided to comply with the rules requiring an abstract that will allow a searcher or other reader to quickly ascertain the subject matter of the technical disclosure.

Claims

1. A computer-implemented method comprising:

receiving a plurality of packet streams input from different endpoints, packets of each stream including header and payload portions, the header portion including first and second portions, the second portion containing audio power level information that includes power levels for each of a respective plurality of frequencies, each power level comprising a moving average of a normalized power level at a particular frequency, the second portion further including timebase information associated with the moving average;

comparing the audio power level information contained in the packets of each of the packet streams at a particular point in time to select N, where N is an integer, greater than or equal to one, packet streams with loudest audio;

decoding the N packet streams to obtain audio content contained in the payload portion of each of the N packet streams; and

mixing the audio content of the N packet streams to produce one or more output packet streams.

2. The computer-implemented method of claim 1, wherein the first portion of the header is encrypted, the second portion of the header containing the audio power level information is unencrypted, and all or a portion of the payload is encrypted.

3. The computer-implemented method of claim 2 wherein each of the packets has a packet format compatible with Secure Real-Time Protocol (SRTP).

4. The computer-implemented method of claim 1 further comprising sending the one or more output packet streams to the different endpoints.

5. The computer-implemented method of claim 1 further comprising discarding a remainder of the packet streams.

6. The computer-implemented method of claim 1 wherein the frequencies include at least one frequency associated with human speech.

7. The computer-implemented method of claim 1 wherein each of the packets has a packet format compatible with Real-Time Protocol (RTP).

8. The computer-implemented method of claim 1 further comprising:

generating a report that contains statistics regarding the audio content and an adjusted timebase; and

sending the report to at least the endpoints associated with the N packet streams.

9. A computer-implemented method comprising:

receiving a plurality of packet streams input from a corresponding plurality of endpoints, packets of each stream including header and payload portions, the header portion containing audio power level information that includes timebase information and a moving average of normalized power levels for each of a respective plurality of frequencies, wherein portions of the header and payload are encrypted the timebase information and the moving average being included in an unencrvpted portion of the header;

comparing the audio power level information contained in the packets of each of the packet streams at a particular point in time to select N, where N is an integer greater than or equal to one, packet streams with loudest audio;

decoding the N packet streams to obtain audio content contained in the payload portion of each of the N packet streams; and

mixing the audio content of the N packet streams to produce N+1 output packet streams.

10. The computer-implemented method of claim 9 wherein N of the output packet streams are each customized for a corresponding one of the endpoints.

11. The computer-implemented method of claim 9 further comprising:

encoding and encrypting each of the output packet streams; and

sending the encoded and encrypted output packet streams to the endpoints.

12. The computer-implemented method of claim 9 wherein the frequencies include at least one frequency associated with human speech.

13. The computer-implemented method of claim 12 wherein the loudest audio of the N packet streams is determined with respect to the at least one frequency.

14. The computer-implemented method of claim 9 further comprising discarding a remainder of the packet streams.

15. The computer-implemented method of claim 14 wherein the remainder of the packet streams includes all of the packet streams, except for the N packet streams.

16. The computer-implemented method of claim 9 wherein the unencrypted portion comprises a Real-Time Protocol (RTP) extension section.

17. A non-transitory machine-readable storage medium encoded with a computer program, when executed, the computer program operable to:

receive a plurality of packet streams input from different endpoints, packets of each stream including encrypted and unencrypted portions, the unencrypted portion containing audio power level information that includes a moving average of normalized power levels for each of a respective plurality of frequencies, the audio power level information further including timebase information associated with the moving average;

compare the audio power level information contained in the packets of each of the packet streams at a particular point in time to select N, where N is an integer greater than or equal to one, packet streams with loudest audio;

decrypt the N packet streams to obtain audio content contained in the encrypted portion of each of the N packet streams; and

mix the audio content of the N packet streams to produce one or more output packet streams.

18. The non-transitory machine-readable storage medium of claim 17 wherein, when executed, the computer program is further operable to send the one or more output packet streams to the different endpoints.

19. The non-transitory machine-readable storage medium of claim 17 wherein, when executed, the computer program is further operable to discard a remainder of the packet streams.

20. The non-transitory machine-readable storage medium of claim 17 wherein the frequencies include at least one frequency associated with human speech.

21. A system comprising:

a conferencing server; and

a mixer coupled to receive control information from the conferencing server, the mixer being operable to;

examine an unencrypted portion of each of a plurality of packets associated with streams input from corresponding endpoints, the unencrypted portion containing audio power level information at one or more frequencies associated with human speech, the audio power level information including a moving average of normalized power levels at the one or more frequencies, the unencrypted portion further including a timebase associated with the moving average;

select, based on the audio power level information, N packet streams having highest power levels, where N is an integer greater than or equal to one;

mix audio content from the N packet streams to produce a plurality of output packet streams; and

send the output packet streams to the endpoints.

22. The system of claim 21 wherein the unencrypted portion comprises a Real-Time Protocol extension section.

23. The system of claim 21 wherein the mixer is further operable to:

generate a report that contains statistics regarding the audio content and an adjusted timebase; and

send the report to at least the endpoints associated with the N packet streams.