Audio communication method and apparatus for watermarking an audio signal with spatial information

1. An audio transmit processor for a transmitter device configured for communication over a network, the audio transmit processor comprising:

an audio capture module configured to

receive at least two audio signals from an audio source,

generate parametric stereo information from the at least two audio signals,

generate spatial information from the at least two audio signals, and

generate a mono audio signal and a non-audio signal from the at least two audio signals, the non-audio signal comprising geographic location coordinates of the transmitter device, the parametric stereo information, and spatial information of the audio source; and

an audio watermarking module coupled to the audio capture module and configured to embed the non-audio signal in the mono audio signal as a watermark in the mono audio signal, wherein the embedded non-audio signal is encoded by Phase Shift Keying (PSK);

a speech codec coupled to the audio watermarking module and configured to encode the mono audio signal embedded with the non-audio signal as the watermark; wherein the encoding comprises compressing the mono audio signal embedded with the non-audio signal as the watermark for transmission; wherein the watermark is recoverable from the compressed mono audio signal embedded with the non-audio signal.

2. The audio transmit processor of claim 1 , wherein the spatial information is representative of one or more of a direction and a position of the audio source.

3. The audio transmit processor of claim 1 , wherein the spatial information comprises at least one of a time-difference-of-arrival difference and an intensity difference between the at least two audio signals.

4. The audio transmit processor of claim 1 , wherein the parametric stereo data comprises at least one of a phase difference between the at least two audio signals per frequency band, a level difference between the at least two audio signals per frequency band, and coherence between the at least two signals per frequency band.

5. The audio transmit processor of claim 1 , wherein the geographic location coordinates are GPS coordinates.

6. The audio transmit processor of claim 1 , wherein each of the at least two audio signals are received from a respective microphone.

7. The audio transmit processor of claim 1 , wherein the audio watermarking module is configured to embed the non-audio signal in the mono audio signal and to output the watermarked mono audio signal by:

filtering the mono audio signal by a filter-bank;

applying sinusoidal amplitude modulations (SAM) to neighboring sub-band signals in an opposite phase;

using the SAM as a carrier; and

encoding the non-audio signal onto the carrier.

8. The audio transmit processor of claim 1 , wherein the audio watermarking module is configured to extract the non-audio signal embedded in the received mono audio signal by:

filtering the received mono audio signal by a filter-bank;

extracting sinusoidal amplitude modulations (SAM) based on a ratio of amplitude envelopes from neighboring sub-band signals;

comparing the SAMS of a base group to those of other groups; and

decoding the non-audio signal based on the comparison.

9. The audio transmit processor of claim 1 , wherein the non-audio signal further indicates a number of microphones to capture the at least two audio signals.

10. An audio receive processor for a receiver device configured for voice communication over a communications network, the audio receive processor comprising:

a speech codec module configured to decode a watermarked mono audio signal having a mono audio signal and a watermark of a non-audio signal embedded in the mono audio signal, wherein the watermarked mono audio signal was compressed by a transmitter speech codec for transmission over the communication network and the decoding comprises a decompression of the watermarked mono audio signal;

an audio watermark extraction module coupled to the speech codec module and configured to extract the non-audio signal embedded in the decoded watermarked mono audio signal, wherein the embedded non-audio signal is encoded by Phase Shift Keying (PSK), the non-audio signal comprising geographic location coordinates of a transmitter device which transmits the watermarked mono audio signal, parametric stereo information, and spatial information of an audio source; and

an audio playback module coupled to the audio watermark extraction module and configured to process the mono signal and the parametric stereo information and spatial information and to provide at least two output audio signals for output via a respective loudspeaker.

11. The audio receive processor of claim 10 , wherein the spatial information is representative of a direction or a spatial position of audio of the audio source captured by a transmitter.

12. The audio receive processor of claim 10 , wherein the audio playback module is further configured to apply upmixing to the mono audio signal in dependence of the spatial information.

13. The audio receive processor of claim 10 , wherein the audio playback module is coupled to the audio watermark extraction module and configured to process the mono signal, the parametric stereo information, and spatial information using acoustic beamforming to position audio associated with the at least two output audio signals based on the spatial information.

14. An audio processor comprising the audio transmit processor of claim 1 .

15. A method for transmitting audio over a communications network, the method comprising:

capturing at least two audio signals from an audio source;

processing the at least two audio signals to provide a mono audio signal and a non-audio signal comprising geographic location coordinates of a transmitter device which transmits the audio, parametric stereo information, and spatial information of the audio source, wherein the non-audio signal is encoded by Phase Shift Keying (PSK);

combining the non-audio signal with the mono audio signal by watermarking the mono audio signal with the non-audio signal; and

outputting the watermarked mono audio signal to a speech codec which encodes the watermarked mono audio signal; wherein the encoding comprises compressing the watermarked mono audio signal for transmission; wherein the watermarked non-audio signal is recoverable from the compressed watermarked mono audio signal.

16. The method of claim 15 , wherein the spatial information is representative of one or more of a direction and a position of the audio source.

17. A method for receiving audio over a communications network comprising:

receiving a watermarked mono audio signal from an audio source, the watermarked mono audio signal having a non-audio signal as a watermark on a mono audio signal;

decoding, by a speech codec, the watermarked mono audio signal, wherein the watermarked mono audio signal was compressed by a transmitter speech codec for transmission over the communication network and the decoding comprises a decompression of the watermarked mono audio signal;

extracting from the decoded watermarked mono audio signal the mono audio signal and the non-audio signal comprising spatial information from the watermarked audio signal, the non-audio signal comprising geographic location coordinates of a transmitter device of the watermarked audio signal, parametric stereo information, and spatial information of the audio source, wherein the non-audio signal is encoded by Phase Shift Keying (PSK); and

processing the mono audio signal and spatial information to generate at least two output audio signals.

18. An audio processor comprising an audio transmit processor and the audio receive processor of claim 10 .