Methods and apparatus to perform audio watermarking and watermark detection and extraction

A non-transitory computer readable medium comprising instructions that, when executed, cause processor circuitry to at least:

• access audio samples to be encoded with one or more data symbols;
• select a first look up table (LUT) from a plurality of LUTs in response to a determination that that the audio samples were not previously encoded, the plurality of LUTs to specify respective different mappings of code frequencies to symbol values;
• select a second LUT from the plurality of LUTs in response to a determination that that the audio samples were previously encoded;
• map the one or more data symbols to code frequencies based on the selected one of the first LUT or the second LUT;
• and
• combine the code frequencies and the audio samples to encode the audio samples with the one or more data symbols.

A method comprising:

• accessing audio samples to be encoded with one or more data symbols;
• selecting a first look up table (LUT) from a plurality of LUTs in response to a determination that that the audio samples were not previously encoded, the plurality of LUTs to specify respective different mappings of code frequencies to symbol values;
• selecting a second LUT from the plurality of LUTs in response to a determination that that the audio samples were previously encoded;
• mapping the one or more data symbols to code frequencies based on the selected one of the first LUT or the second LUT;
• and
• combining the code frequencies and the audio samples to encode the audio samples with the one or more data symbols.