AVPC-Subband Coding System for Speech Encoding

The combination of Vector Quantization (VQ) and predictive techniques -named AVPC systems- has been shown as interesting systems for speech waveform coding at medium-high rates (ref. 1 to 3). In this work we present a such system including a previous four subbbands splitting. This allows good quality of speech at low-medium rates (1-1.25 bits/sample). A comparative study show that the AVPC-SBC outperforms the simple AVPC coder.Peer ReviewedPostprint (published version

A continuously adaptive vector predictive coder (AVPC) for speech encoding

In this work we present a waveform speech coding system including vector quantization. This system can be seen as a vector version of the scalar ADPCM speech coder. In such system the speech samples are grouped in vectors that are coded by a vector quantizer when its prediction subtraction has been made. This prediction is obtained in the coder by a vector predictor. Due to the non-stationarity of the speech signal, the code must be continuously adapted to the local characteristics of the current input signal of the speech. We propose the use of an adaptive vector predictor that follows the speech statistics variations so the prediction error to be coded presents the minimum dynamic range. On the other side it is wellknown that the prediction error is proportional to the signal energy. To compensate this effect a vector quantizerPeer ReviewedPostprint (published version

AVPC-Subband Coding System for Speech Encoding

The combination of Vector Quantization (VQ) and predictive techniques -named AVPC systems- has been shown as interesting systems for speech waveform coding at medium-high rates (ref. 1 to 3). In this work we present a such system including a previous four subbbands splitting. This allows good quality of speech at low-medium rates (1-1.25 bits/sample). A comparative study show that the AVPC-SBC outperforms the simple AVPC coder.Peer Reviewe