Patent ID: 6266643
Filing Date: 2001-07-24
Classification: G10L

Abstract:
A method for eliminating superfluous information from an audio signal using a Fourier transform permitting the audio signal to be speeded up without a subsequent change in pitch, the method including the steps:A) separating the audio signal into a series of chunks (frames or subframes),B) performing a Fourier transformation on each one of said chunks, revealing sine and cosine Fourier coefficients for each of a large number of frequencies in each one of said chunks,C) averaging the absolute values of the sine and the cosine Fourier coefficients for each one of a large number of frequencies in each one of said chunks, determining the occurrence of one or more of the highest averaged absolute value(s) of sine and cosine Fourier coefficients for said large number of frequencies within one or more of said chunks, said highest averaged absolute value(s) to be called the dominant frequency(ies) or ""signature"",D) comparing each one of said dominant frequency(ies) in each one of said chunks with each one of said dominant frequency(ies) of the next one of said chunks in said series, marking each chunk with said dominant frequency(ies) substantially identical to the said dominant frequency(ies) of the previous chunk in said series,E) removing said marked chunk(s) from said series of chunks, providing a shortened signal, andF) saving the remaining data of unmarked information for replay, whereby, when said audio signal is played, the duration of the signal is lessened without a consequent change in pitch.