Multi-mode audio recognition and auxiliary data encoding and decoding

A method of embedding a watermark in an electronic audio signal, the method comprising:

• determining whether an audio segment of the audio signal is stationary or non-stationary;
• adapting resolution of a perceptual model based on whether the audio segment is stationary or non-stationary;
• and
• inserting a watermark into the audio segment using the adapted perceptual model.

A method of embedding a watermark in an electronic audio signal, the method comprising:

• generating a watermark signal for insertion into the electronic audio signal;
• evaluating perceptual audio quality of the electronic audio signal relative to changes of that electronic audio signal corresponding to the watermark signal through automated application of a perceptual audio quality measure that computes audio quality parameters based on a human auditory model, including parameters for estimating quality based on a difference between the audio signal and a watermarked version of the audio signal;
• updating a watermark embedding parameter based on the evaluating;
• embedding the watermark signal into the electronic audio signal using the updated watermark embedding parameter
• analyzing the audio signal for a harmonic;
• and
• for embedding locations corresponding to the harmonic, structuring the watermark signal to be masked by the harmonic.

A method of embedding a watermark in an electronic audio signal, the method comprising:

• generating a watermark signal using orthogonal frequency division multiplexing in which auxiliary data is modulated onto OFDM carrier signals;
• computing a frequency magnitude envelope for embedding locations in a frequency domain transform of the audio signal;
• inserting the watermark signal by replacing audio signal frequency components with modulated OFDM carrier signals at the embedding locations while maintaining the frequency magnitude envelope at the embedding locations, and
• weighting the audio signal in a frequency range from 16 to at least 19 Khz, the weighting being selected to counter a drop in frequency response of audio equipment over the frequency range from 16 to at least 19 Khz.

A non-transitory computer readable medium, on which is stored instructions, which when executed by a processor perform a method of embedding a watermark in an electronic audio signal, the method comprising:

• analyzing the audio signal to identify an embedding location that does not have sufficient signal in which to embed a watermark signal element;
• boosting the audio signal at the embedding location;
• and
• embedding the watermark signal element at the embedding location, using the boosting to mask audibility of a change in the audio signal made to embed the watermark signal.