METHODS FOR ENCODING, DECODING AND INTERPRETING AUXILIARY DATA IN MEDIA SIGNALS

1 . A variable message payload method for creating a payload in a data structure, comprising:

forming a payload item identifier in a first portion of a payload field that identifies a payload item conveyed in a second portion of the payload field, in which the payload item identifier identifies a payload item sub-type to inform decoding of the payload item, the payload item representing a sell-by date, an expiration date or a best-if-used-by date;

forming error-correction bits to authenticate the payload field; and

embedding the payload item identifier, error-correction bits, and the payload item into a host media signal.

2 . The method of claim 1 , wherein the data structure comprises a digital watermark.

3 . The method of claim 1 , wherein embedding comprises embedding such that the data structure is substantially imperceptible in the host media signal.

4 . (canceled)

5 . The method of claim 1 , wherein the identifier includes a global trade item number (GTIN), an application identifier (AI), or a recycling code.

6 . A method for interpreting a data structure having fixed and variable message portions, the method comprising:

processing the fixed message portion to determine a version of the variable message portion, in which the fixed message portion identifies a type of error correction;

decoding a payload field of the variable message portion according to the determined version, including applying an error correction process to validate the variable message portion corresponding the type of error correction;

determining a payload item identifier in a first portion of a payload field of the decoded variable message portion, in which the payload item identifier identifies a payload item sub-type to inform interpretation of a payload item conveyed in a second portion of the decoded payload field, the payload item representing a sell-by date, an expiration date or a best-if-used-by date; and

interpreting the payload item conveyed in the second portion of the decoded payload field according to the determined payload item identifier.

7 . A method for interpreting a data structure having fixed and variable message portions, the method comprising:

processing the fixed message portion to determine a version of the variable message portion, the fixed message portion comprising a validation portion and a version portion, said processing obtaining plural-bit data from the version portion, in which the validation portion comprises a fixed set of message symbols to provide a check to confirm valid processing;

decoding only a portion of the payload field of the variable message portion according to the determined version, in which the variable message portion comprises error detect symbols including a type and length of Cyclic Redundancy Check (CRC) symbol; and

interpreting a payload item conveyed in the decoded portion of the payload field.

8 . (canceled)

9 . A system, comprising:

a processor; and

a memory coupled to the computer processor, the memory storing instructions that, when executed by the processor, cause the processor to perform the method recited in of claim 6 .

10 . The system of claim 9 , further comprising at least one capture device configured to capture a host media signal in which the data structure is encoded.

11 . The system of claim 10 , wherein the at least one capture device comprises a microphone, a camera and an accelerometer.

12 . A non-transitory computer readable storage medium storing therein instructions that, when executed by a processor in a system cause the processor to perform the method recited in any of claim 6 .