Methods and apparatus for characterizing media are described. In one example, a method of characterizing media includes capturing a block of audio; converting at least a portion of the block of audio into a frequency domain representation including a plurality of complex-valued frequency components; defining a band of complex-valued frequency components for consideration; determining a decision metric using the band of complex-valued frequency components; and determining a signature bit based on a value of the decision metric. Other examples are shown and described.
