1. A method for controlling operation of a device using a watermark comprising: decoding a watermark embedded in a signal of a media type, where the watermark includes a command signal used to trigger a change in operation of the watermark detector; based on the command signal, changing operation of the watermark detector, including changing how the watermark detector decodes or interprets a watermark in a signal of the media type; after changing operation of the watermark detector, decoding a usage control restriction from a watermark embedded in the signal.