Speech playback speed change using wavelet coding preferably sub-band coding

摘要

A method of speeding up playback of a digitised audio signal without raising the pitch and without introducing discontinuities in the speech signal, comprises sub-band coding (SBC) consecutive blocks of the audio signal with standard SBC or wavelet compression to derive frames of data. Next periodic adjacent pairs of the frames are dropped to leave a stream of remaining frames. A sped up approximation of the digitised audio signal is then reconstructed by sub-band decoding consecutive remaining frames. The method can also be used to slow speech playback by replicating, rather than dropping, adjacent pairs of frames.