Peter Kroon

CS-ACELP speech compression system with adaptive pitch prediction filter gain based on a measure of periodicity

A speech coding system employing an adaptive codebook model of periodicity is augmented with a pitch-predictive filter (PPF). This PPF has a delay equal to the integer component of the pitch-period and a gain which is adaptive based on a measure of periodicity of the speech signal. In accordance with an embodiment of the present invention, speech processing systems which include a first portion comprising an adaptive codebook and corresponding adaptive codebook amplifier and a second portion comprising a fixed codebook coupled to a pitch filter, are adapted to delay the adaptive codebook gain; determine the pitch filter gain based on the delayed adaptive codebook gain, and amplify samples of a signal in the pitch filter based on said determined pitch filter gain. The adaptive codebook gain is delayed for one subframe. The pitch filter gain equals the delayed. adaptive codebook gain, except when the adaptive codebook gain is either less than 0.2 or greater than 0.8., in which cases the pitch filter gain is set equal to 0.2 or 0.8, respectively.

Dichotic presentation of interleaving critical-band envelopes: an application to multi-descriptive coding

A coding paradigm is proposed which is based solely on the properties of the human auditory system and does not assume any specific source properties. Hence, its performance is equally good for speech, noisy speech, and music signals. The signal decomposition in the proposed paradigm takes advantage of binaural properties of the human auditory system. This also leads to a natural multi-descriptive signal representation.