An encoding system for encoding a first ancillary code in media data and monitoring for reception of a second ancillary code that has a higher priority than the first ancillary code, such that upon detection of the higher priority ancillary code the encoding system modifies a characteristic and/or characteristics...http://www.google.de/patents/US7174151?utm_source=gb-gplus-sharePatent US7174151 - Ensuring EAS performance in audio signal encoding
