Patent ID: 8352259

Claim:
An apparatus for generating an audio fingerprint, comprising: a processor operable to: extract a plurality of frequencies from two or more audio source files included in a set of audio source files, wherein the two or more audio source files are encoded in different formats; measure, across the two or more audio source files, a range of variation of each of the plurality of frequencies, the range of variation of a respective frequency being a range of variation of values for the frequency measured from among the two or more audio source files; for each of the plurality of frequencies, compare the range of variation to a corresponding threshold to determine whether the range of variation is less than the corresponding threshold; identify a plurality of stable frequencies from among the plurality of frequencies extracted from two or more audio source files, an extracted frequency being identified as a stable frequency if the respective range of variation is determined to be less than the corresponding threshold; identify harmonically related stable frequencies from among the identified plurality of stable frequencies, each group of harmonically related stable frequencies forming a stable frequency family; map sample points of an unknown recording to at least a portion of at least one stable frequency family; generate fingerprint data by analyzing the mapped sample points of the unknown recording; and form the audio fingerprint from the generated fingerprint data.