On optimal and minimum-entropy decoding

In the quantization of a signal in speech coding, dependencies between its samples are often neglected. Generally, these dependencies are then also neglected at the decoder. However, usually a priori information about these dependencies is available, making it possible to improve decoder performance by means of enhanced decoding. An attractive feature of enhanced decoding is that it can be applied to existing coding standards. This paper describes several enhanced decoding methods, including a vector decoding method and a method which aims at reducing the differential entropy rate of the decoded signal. Experimental results are used to confirm that both these decoding procedures can provide better performance than conventional decoding for common signal/encoder combinations.