16 Kbps sub-band coder incorporating variable overhead information

In this paper, a new block companded quantization method involving a variable rate strategy for transmission of the overhead information is proposed and applied to 16 kbps sub-band coding. In the first part of the paper, the basic sub-band coding technique with fixed rate for transmission of the block quantizer overhead information is reminded. Then, two algorithms for variable rate strategy are described, which are based on a classification of processed blocks into stationary and transient ones. These algorithms are incorporated into three sub-band coders operating at 16 kbps: a 16 sub-band and an 8 sub-band coders based on a uniform analysis, and an 8 sub-band coder based on a non-uniform analysis according to the articulatory index. The evaluation of the coders is based on comparative listening tests, and shows the efficiency of the variable rate strategy.