METHOD TO CODE/DECODE INDICES OF CODE BOOK FOR QUANTISED SPECTRUM OF MDCT IN SCALES VOICE AND AUDIO CODECS Russian patent published in 2011 - IPC G10L19/14 H03M7/00 

FIELD: information technologies.

SUBSTANCE: indices of a code book for a scaled voice and audio codec may be efficiently coded on the basis of proposed distributions of probability for such indices of the code book. For this purpose a residual signal is received from a coding level on the basis of linear forecasting with code excitation, where the residual signal is the difference between the initial audio signal and the reconstructed version of the initial audio signal. The residual signal is transformed at the level of transformation of discrete cosine transformation type to produce the appropriate spectrum of transformation, which is divided into multiple spectral ranges, every of which has multiple spectral lines. Multiple different code books are selected to code spectral ranges, where each code book is connected to the code book index. Then multiple code book indices connected with selected code books are jointly coded to receive a descriptor code, which more compactly presents code book indices.

EFFECT: reduced volume of saved or transmitted information.

33 cl, 15 dwg