Variable encoding and detection apparatus and methods

1. A method of decoding a media signal, comprising:

using a processor to determine a physical environment type associated with the media signal by determining that the physical environment type is an in-home environment or an out-of-home environment;

selecting a decoding mode based on the physical environment type; and

decoding a code from the media signal using the selected decoding mode.

2. A method as defined in claim 1 , wherein using the processor to determine the physical environment type comprises analyzing acoustic characteristics of the physical environment based on the media signal.

3. A method of decoding a media signal, comprising:

using a processor to determine a physical environment type associated with the media signal by analyzing a frequency spectrum or a signal amplitude of the media signal;

selecting a decoding mode based on the physical environment type; and

decoding a code from the media signal using the selected decoding mode.

4. A method of decoding a media signal, comprising:

using a processor to determine a physical environment type associated with the media signal by extracting the code from the media signal and analyzing characteristics of the code;

selecting a decoding mode based on the physical environment type; and

decoding a code from the media signal using the selected decoding mode.

5. A method as defined in claim 4 , wherein analyzing the characteristics of the code comprises at least one of analyzing a power level of the code, analyzing a frequency spectrum of the code, or comparing the code to information stored in a database.

6. A method of decoding a media signal, comprising:

using a processor to determine a physical environment type associated with the media signal by extracting a plurality of codes from the media signal and comparing at least one of the extracted codes to another one of the extracted codes;

selecting a decoding mode based on the physical environment type; and

decoding a code from the media signal using the selected decoding mode.

7. A method of decoding a media signal, comprising:

using a processor to determine a physical environment type associated with the media signal by obtaining via a portable metering device a base metering device identification code emitted by a base metering device;

selecting a decoding mode based on the physical environment type; and

decoding a code from the media signal using the selected decoding mode.

8. A method of decoding a media signal, comprising:

using a processor to determine a physical environment type associated with the media signal;

selecting a decoding mode based on the physical environment type by selecting a code detection threshold; and

decoding a code from the media signal using the selected decoding mode.

9. A method as defined in claim 8 , wherein the code detection threshold is at least one of an amplitude threshold or a frequency threshold.

10. A method of decoding a media signal, comprising:

using a processor to determine a physical environment type associated with the media signal;

selecting a decoding mode based on the physical environment type by adjusting a gain setting of an automatic gain control circuit; and

decoding a code from the media signal using the selected decoding mode.

11. A method of decoding a media signal, comprising:

using a processor to determine whether to obtain the media signal via a portable metering device or a base metering device by determining that the portable metering device and the base metering device are located within different rooms of a household;

determining a physical environment type associated with the media signal;

selecting a decoding mode based on the physical environment type; and

decoding a code from the media signal using the selected decoding mode.

12. A method of decoding a media signal, comprising:

using a processor to determine whether to obtain the media signal via a portable metering device or a base metering device, by:

emitting a plurality of presence codes via the portable metering device; and

determining that the amount of time since the base metering device last received a presence code from the portable metering device is greater than a time threshold;

determining a physical environment type associated with the media signal;

selecting a decoding mode based on the physical environment type; and

decoding a code from the media signal using the selected decoding mode.