Methods and apparatus for inserting audience measurement data or interactive data into a compressed data bitstream are disclosed. An example apparatus disclosed herein includes a parser to access compressed audio data packets from a compressed data bitstream, a time shifter to time shift the compressed audio data packets in data frames of the compressed data bitstream to occupy locations of the data frames from which skip bytes are eliminated, and an inserter to insert at least one of audience measurement data or interactive data into auxiliary data fields of the data frames that increase in size due to the time shifting the compressed audio data.