Audio coding at low bitrates typically suffers from artifacts

caused by bandwidth truncation.

In this paper we present a novel scheme to code audio signals at low

bitrates which uses a traditional scalar quantization followed by

entropy coding to code some portions of the spectrum (typically the lower

portion).

The other portions (typically the higher portions)

of the spectrum are coded at a low bitrate

using an adaptive gain

shape vector quantizer where the codebook for vector quantization

is formed by unmodified or

modified versions of the portions of the spectrum which have already

been coded.

Fixed pre-trained codebooks are also available for use in certain

cases.

The use of such a scheme results in an audio codec which has been

shown to be among the best audio codecs available at low bitrates.

In addition, the decoder complexity of this audio codec is significantly lower

than any other codec of equal quality at low bitrates.

PDF file

In  Proc. Workshop on Multimedia Signal Processing

Publisher  IEEE
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