A Study on Subband Audio Signal Compression Technique

• Main Authors: Lui-Min Hwang, 黃裕閔
• Other Authors: Tzong-Yeu Leou
• Format: Others
• Language: zh-TW
• Published: 1995
• Online Access: http://ndltd.ncl.edu.tw/handle/40689679445500395195

碩士 === 國立臺灣科技大學 === 工程技術研究所 === 83 === This paper explores the application of subband coding techn ique to high quality audio compression. When compressing audio s ignals, coding error inevitably exist in the reconstructed signa ls. To maintain the quality of the original audio signals, it is necessary to make the coding error inaudible. Thus, the masking e ffect of the human hearing characteristics can be fully utilized to minimize the effect of coding errors. In this paper, we close ly examine the masking effect and judiciously apply it to the au dio signal compression. In the audio signal coding technique, we will record the ma ximum amplitude of each subband signal as side information. To r educe the bit rate further, a common maximum value will be chose n for a adjacent and closely correlated frames. Only a single s et of maximum values are transmitted for the save collection of subband signals, which significantly reduces the amount of side information needed to be transmitted. To minimize the quantizati on error, we adopt the u-law quantization scheme in signals, qua ntization and the optimal value of u is determined for a set of training audio signals.