Apparatus and methods for watermarking using starting phase modulation

A method comprising:

• determining a first phase value for a first watermark component at a sample time;
• determining a second phase value for a second watermark component at the sample time;
• determining that the first phase value and the second phase value are sufficiently close to a starting phase value selected to carry information;
• and
• determining, by a computing system, a payload based at least in part on the starting phase value.

A non-transitory computer-readable medium having stored therein instructions that, when executed by a computing system, cause the computing system to perform a set of operations comprising:

• determining a first phase value for a first watermark component at a sample time;
• determining a second phase value for a second watermark component at the sample time;
• determining that the first phase value and the second phase value are sufficiently close to a starting phase value selected to carry information;
• and
• determining a payload based at least in part on the starting phase value.