Temporally accurate watermarking system and method of operation

1. A system for identifying audio data comprising:

a transform system for receiving left channel audio data and right channel audio data and electronically generating a plurality of frequency bins of left channel magnitude data, left channel phase data, right channel magnitude data and right channel phase data;

a watermarking system for receiving watermarking data and electronically modifying predetermined frequency bins of the left channel phase data and the right channel phase data to encode the watermarking data;

a magnitude system for receiving the left channel magnitude data and the right channel magnitude data and increasing the left channel magnitude data and the right channel magnitude data for one or more of the predetermined frequency bins to a threshold level if the left channel magnitude data and the right channel magnitude data for the corresponding frequency bin are less than the threshold level; and

a timing system for receiving a plurality of bits of timing data and modifying two or more predetermined frequency bins of the left channel phase data and two or more predetermined frequency bins of the right channel phase data to encode each bit of the timing data;

wherein the predetermined frequency bins of the left channel phase data and the right channel phase data that are used to encode timing data are modified by different phase angles than the predetermined frequency bins of the left channel phase data and the right channel phase data that are used to encode watermarking data.

2. The system of claim 1 further comprising a frame adjustment system for receiving frame sequence data and modifying the timing data based on the frame sequence data.

3. The system of claim 1 wherein the transform system comprises:

a right channel transform system for receiving the right channel audio data and generating the plurality of frequency bins of the right channel magnitude data and the right channel phase data;

a left channel transform system for receiving the left channel audio data and generating the plurality of frequency bins of the left channel magnitude data and the left channel phase data.

4. The system of claim 1 wherein the magnitude system comprises:

a right channel magnitude system for receiving the right channel magnitude data and increasing the right channel magnitude data for one or more of the predetermined frequency bins to a threshold level if the right channel magnitude data for the corresponding frequency bin is less than the threshold level; and

a left channel magnitude system for receiving the left channel magnitude data and increasing the left channel magnitude data for one or more of the predetermined frequency bins to a threshold level if the left channel magnitude data for the corresponding frequency bin is less than the threshold level.

5. A method for identifying audio data comprising:

receiving left channel audio data and right channel audio data;

converting the left channel audio data and the right channel audio data into a plurality of bins of left channel phase data, left channel magnitude data, right channel phase data and right channel magnitude data;

encoding watermark data by electronically modifying a phase difference between the left channel phase data and the right channel phase data for each of a plurality of predetermined bins;

adjusting the left channel magnitude data and the right channel magnitude data for each of the plurality of predetermined bins to a predetermined threshold if the left channel magnitude data and the right channel magnitude data is less than the predetermined threshold; and

receiving a plurality of bits of timing data and modifying two or more predetermined frequency bins of the left channel phase data and two or more predetermined frequency bins of the right channel phase data to encode each bit of the timing data;

wherein the predetermined frequency bins of the left channel phase data and the right channel phase data that are used to encode timing data are modified by different phase angles than the predetermined frequency bins of the left channel phase data and the right channel phase data that are used to encode watermarking data.

6. The method of claim 5 further comprising converting the plurality of bins of modified left channel phase data, adjusted left channel magnitude data, modified right channel phase data and adjusted right channel magnitude data into watermarked left channel audio data and watermarked right channel audio data.

7. The method of claim 5 wherein encoding the watermark data by modifying the phase difference between the left channel phase data and the right channel phase data for each of the plurality of predetermined bins comprises:

modifying the phase difference between the left channel phase data and the right channel phase data for each of a first plurality of predetermined bins based on a first bit of the watermark data; and

modifying the phase difference between the left channel phase data and the right channel phase data for each of a second plurality of predetermined bins based on a second bit of the watermark data.

8. The method of claim 5 wherein encoding the watermark data by modifying the phase difference between the left channel phase data and the right channel phase data for each of the plurality of predetermined bins comprises:

modifying the phase difference between the left channel phase data and the right channel phase data for each of a first plurality of predetermined bins based on a first bit of the watermark data; and

modifying the phase difference between the left channel phase data and the right channel phase data for each of a second plurality of predetermined bins based on the first bit of the watermark data.