Patent ID: 8140331

Claim:
A method for extracting audio features from a plurality of audio frames to classify said plurality of audio frames into acoustically similar groups, the method comprising: transforming each audio frame of said plurality of audio frames into a plurality of frequency sub-bands to obtain a transformation result; Storing the transformation results for the plurality of audio frames as sub-band coefficients in S, wherein each sub-band coefficient correlates to an audio frame at a time slice with a frequency sub-band; for each time slice of S, subtracting each of the sub-band coefficient within the same time slice from a mean value corresponding to the same time slice to obtain a set of new sub-band coefficient; storing the sets of new sub-band coefficients for all the time slices in Z; calculating a beat matrix from Z and storing the beat matrix in B, wherein a first axis of B corresponding to a time slice and a second axis of B corresponding to a frequency sub-band, and wherein each nonzero entry in B corresponds to a beat onset of the audio frames at each frequency sub-band; calculating a plurality of quantized coefficients from Z according to at least one quantization threshold and storing the quantized coefficients in A; calculating a plurality of intra-band features from B, wherein the intra-band features correlate to beat signatures of the audio frames at a frequency sub-band; and calculating a plurality of inter-band features from A, wherein the inter-band features correlate to changes among the frequency sub-bands of the audio frames.