An Improvement Of G.719Audio Codec

G.719, which is the first low-complexity full-band audio codec for high-qualityconversational applications, is proposed by ITU-T in2008. In the coding algorithm, themodified discrete cosine transform (MDCT) is adopted for adaptive time-frequencytransform. The MDCT coefficients are quantized by lattice vector quantization (LVQ), andthen Huffman coding is used to encode them.Trellis Coded Quantization (TCQ) is a method between the scalar quantization and thevector quantization, it can almost achieve the performance of the vector quantization with amoderate complexity. Arithmetic Coding (AC) is an entropy coding method with highcompression efficiency. And the Arithmetic Coded Trellis Coded Quantization (ACTCQ),which is the combination of TCQ and AC.In order to improve the quality of the reconstructed audio signal, ACTCQ is applied toG.719audio codec for improvement in this paper. The experimental results show that,compared with the G.719audio codec, the improved codec not only reduces the coding rate,but also obviously improves the quality of the reconstructed audio.