Audio coding/decoding method and apparatus using excess quantization information

Abstract

There is provided an audio coding device which appropriately sets the quantization bit number by a small calculation amount in each stage when coding an input audio signal by performing multi-stage normalization/quantization. A quantization information calculation section determines total quantization information idwl, based on normalization information idsf, and allocates the total quantization information idwlfor quantization information idwland quantization information idwl. At this time, the quantization information calculation section limits the quantization information idwlby a limiter lim, and allocates the total quantization information idwlfor quantization information idwl. If the quantization information idwlexceeds the limiter lim, the excess is allocated for the quantization information idwl. A first normalization section and a first quantization section normalizes and quantizes a frequency spectrum mdspecin the first stage. A second normalization section and a second quantization section normalizes and quantizes a differential frequency spectrum mdspecin the second stage.