A method of generating a characteristic signature of media comprising: capturing a block of audio; converting at least a portion of the block of audio into a frequency domain representation; dividing the frequency domain representation into a plurality of frequency bands, the plurality of frequency bands having respective band indices; determining a characteristic difference (d i) of a first frequency band of the plurality of frequency bands corresponding to a selected band index by: when a value of a counter (i) representative of the selected band index is odd, subtracting a second energy (E T i+1) of a second frequency band in the plurality of frequency bands from a first energy (E t i) of the first frequency band, the second energy (E T i+1) corresponding to a second time preceding a first time corresponding to the first energy, the second frequency band being a higher neighboring frequency band than the first frequency band; or when the value (i) of the counter is even, subtracting a third energy (E T i-1) of a third frequency band in the plurality of frequency bands from the first energy (E t i) of the first frequency band, the third energy (E T i-1) corresponding to a third time preceding the first time, the third frequency band being a lower neighboring frequency band than the first frequency band; and determining a signature bit of a characteristic signature of the block of audio by determining (606, 612) if the characteristic difference (d i) is positive and, in response to determining the characteristic difference (d i) being positive, comparing (606, 612) the characteristic difference (d i) with a negative of a characteristic difference of another frequency band of the plurality of frequency bands having a band index that is higher (d i+1) than the selected band index (i) when the value (i) of the counter is odd or lower (d i-1) than the selected band index (i) when the value (i) of the counter is even. capturing a block of audio; converting at least a portion of the block of audio into a frequency domain representation; dividing the frequency domain representation into a plurality of frequency bands, the plurality of frequency bands having respective band indices; determining a characteristic difference (d i) of a first frequency band of the plurality of frequency bands corresponding to a selected band index by: when a value of a counter (i) representative of the selected band index is odd, subtracting a second energy (E T i+1) of a second frequency band in the plurality of frequency bands from a first energy (E t i) of the first frequency band, the second energy (E T i+1) corresponding to a second time preceding a first time corresponding to the first energy, the second frequency band being a higher neighboring frequency band than the first frequency band; or when the value (i) of the counter is even, subtracting a third energy (E T i-1) of a third frequency band in the plurality of frequency bands from the first energy (E t i) of the first frequency band, the third energy (E T i-1) corresponding to a third time preceding the first time, the third frequency band being a lower neighboring frequency band than the first frequency band; and when a value of a counter (i) representative of the selected band index is odd, subtracting a second energy (E T i+1) of a second frequency band in the plurality of frequency bands from a first energy (E t i) of the first frequency band, the second energy (E T i+1) corresponding to a second time preceding a first time corresponding to the first energy, the second frequency band being a higher neighboring frequency band than the first frequency band; or when the value (i) of the counter is even, subtracting a third energy (E T i-1) of a third frequency band in the plurality of frequency bands from the first energy (E t i) of the first frequency band, the third energy (E T i-1) corresponding to a third time preceding the first time, the third frequency band being a lower neighboring frequency band than the first frequency band; and determining a signature bit of a characteristic signature of the block of audio by determining (606, 612) if the characteristic difference (d i) is positive and, in response to determining the characteristic difference (d i) being positive, comparing (606, 612) the characteristic difference (d i) with a negative of a characteristic difference of another frequency band of the plurality of frequency bands having a band index that is higher (d i+1) than the selected band index (i) when the value (i) of the counter is odd or lower (d i-1) than the selected band index (i) when the value (i) of the counter is even.