IMPROVED ENCODING OF AN IMPROVEMENT STAGE IN A HIERARCHICAL ENCODER

摘要

A method and coding device are provided for coding a digital audio input signal in a hierarchical coder, which includes a core coding stage with B bits and at least one current improvement coding stage k, delivering quantization indices which are concatenated to form the indices of a preceding embedded coder. The method includes: obtaining possible quantization values for the current improvement stage k by determining absolute reconstruction levels of just the current stage k on the basis of the indices of the preceding embedded coder; and quantizing the input signal of the hierarchical coder having undergone or not a perceptual weighting processing, on the basis of the possible quantization values so as to form a scalar quantization index for the stage k and a quantized signal corresponding to one of the possible quantization values.