Inserting watermarks into audio signals that have speech-like properties

A method for a machine or group of machines to watermark an audio signal, the method comprising:

• receiving an audio signal;
• receiving watermark data payload information;
• converting the watermark data payload information into a watermark audio signal including one or more watermark messages corresponding to the watermark data payload information, each of the one or more watermark messages comprising multiple symbols, each of the multiple symbols corresponding to a respective audio segment;
• and
• inserting the one or more watermark messages into multiple spectral channels of the audio signal, wherein each of the multiple spectral channels occupies a different frequency range, wherein, once an audio segment has been inserted into a spectral channel of the audio signal, amplitude of the audio segment is held constant for the time duration of the audio segment such that a first portion of the audio segment is masked by the audio signal and a second portion of the audio segment is not masked by the audio signal.

A machine or group of machines for watermarking audio, comprising:

• an input that receives an audio signal and watermark data payload information;
• an encoder configured to convert the watermark data payload information into a watermark audio signal including one or more watermark messages corresponding to the watermark data payload information, each of the one or more watermark messages comprising multiple symbols, each of the multiple symbols corresponding to a respective audio segment;
• and
• a processor configured to insert the one or more watermark messages into multiple spectral channels of the audio signal, wherein each of the multiple spectral channels occupies a different frequency range, wherein the processor is configured to insert the one or more watermark messages such that, once the processor has inserted an audio segment into a spectral channel of the audio signal, amplitude of the audio segment is held constant for the time duration of the audio segment regardless of whether the amplitude of the audio segment is masked by the audio signal resulting in a portion of the audio segment being masked by the audio signal and a second portion of the audio segment not being masked by the audio signal.