The lossless adaptive arithmetic coding based on context for ITU-T G.719 at variable rate

This paper presents a novel technique of context-based adaptive arithmetic coding of the quantized MDCT coefficients and frequency band gains in audio compression. A key feature of the new technique is combining the context model in time domain and frequency domain, which used for the quantized norms' and MDCT coefficients' probability. With this new technique, we achieve a high degree of adaptation and redundancy reduction in the adaptive arithmetic coding. In addition, we employ an efficient variable rate algorithm for G.719. The variable rate algorithm is designed based on the baseline entropy coding method of G.719 and the proposed adaptive arithmetic coding technique respectively. For a set of audio samples used in the application, we achieve an average bit-rate saving of 7.2% while producing audio quality equal to that of the original G.719.