Search

This paper proposes a tonal component coding algorithm for a codec that employs a transform followed by Huffman coding, such as MPEG-2 Audio AAC (advanced audio coding) [1]. After the input audio signal is mapped onto the frequency domain, the proposed algorithm removes local maxima components that degrade the coding efficiency. As a result of this withdrawal, the flatness of the spectrum increases and the efficiency of Huffman coding is improved. The removed components are encoded separately as side information. When the frequency resolution of the time/frequency mapping is high, this algorithm works more effectively since local maximum samples appear more frequently with such a mapping. Simulation results show that this algorithm achieves as much as an 11% bit reduction per frame and improves the coding efficiency in 41% of all audio frames. ©1999 Scripta Technica, Electron Comm Jpn Pt 3, 82(4): 71–78, 1999 [ABSTRACT FROM AUTHOR]