本論文主要是以MPEG-1 Layer III（MP3）音訊壓縮編碼器之實現與研究為主，並針對MP3 在低位元率時的缺失，提出編碼效能分析及音質的改善。首先，我們利用低通濾波器與適應性頻譜截斷法將MP3 低位元率編碼的缺點加以修正；然後，再針對上述方法之缺點加以改良，提出高頻補償法以補償高頻缺失的部分，使得MP3 音訊壓縮編碼器於低位元率的編碼效能及音質更加完善。

The research of this thesis is mainly focused on study and implementation of MPEG-1 Layer III (MP3) for low bit-rate applications. First, we propose a lowpass filter approach and its daptive spectrum reduction method to reduce the defeat of the MP3 codec in low bit-rate applications. Both lowpass and spectrum reduction algorithms will sacrifice the high frequency components of audio signals. To improve the high frequency performance, we further suggest a high frequency compensation method to make up the quasi-harmonics of high frequency spectrum. By using spectrum reduction
and quasi-harmonic compensation method, the MPEG-1 Layer III audio coder can achieve a high perceptual quality for low bit-rate applications.

第一章數位音訊編碼簡介................................................. 1
第二章MPEG-1 Layer III 編解碼器....................................... 13
第三章MPEG-1 Layer III 在低位元率的效能............................... 34
第四章MPEG-1 Layer III 之高頻補償..................................... 48
第五章結論............................................................ 60
參考文獻.............................................................. 61

[1] E. Zwicker and H. Fastl, “Psychoacoustics - Facts and Models,” Springer Press,1999
[2] ISO/IEC JTC1/SC29/WG11 MPEG, “Information technology - Coding of moving
pictures and associated audio for digital storage media at up to about 1.5 Mbit/s, Part 3: Audio,” IS11172-3, 1993.
[3] S. Shlien, “Guide to MPEG-1 Audio Standard,” IEEE Transactions on Broadcasting,Vol. 40, No. 4, December 1994.
[4] D. Pan, “A Tutorial on MPEG/Audio Compression,” IEEE Trans. on Multimedia, Vol.2, No. 2, pp. 60-74, 1995.
[5] P. Noll, “MPEG Digital Audio Coding,” IEEE Signal Processing Magazine, September 1997.
[6] T. Painter and A. Spanias, “Perceptual Coding of Digital Audio,” Processing of the IEEE, Vol. 88, No. 4, April 2000.
[7] C.A. Lanciani, “Audio Perception and the MPEG Audio Standard – A Qualifying Examination Report,” Georgia Institute of Technology School of Electrical and Computer Engineering, August 11, 1995.
[8] J. Princen and A. Bradley, “Analysis/Synthesis Filterbank Design Based on Time Domain Aliasing Cancellation,” IEEE Trans. on Acoust. Speech, and Signal Process. Vol. ASSP-34, pp. 1153-1161, 1986.
[9] J. Princen, A. Johnson, and A. Bradley, “Subband/Transform Coding Technique
Based on Time Domain Aliasing Cancellation,” Proc. Int’l Conf. IEEE ASSP, IEEE
Press, Piscatawan, N.J., pp. 2161-2164, 1987.
[10] J. Watkinson, “The MPEG Handbook,” Focal Press, 2001.
[11] Y.H Lam and R.W. Stewart, “Digital Filtering for Audio Coding,” An Enabling Technology (Ref. No. 1998/252), IEE Colloquium on, 1998.
[12] D.Y Pan, “Digital Audio Compression,” Digital Technical Journal Vol. 5 No. 2, Spring, 1993.
[13] F. Wylie, “Digital audio data compression,” Electronics & Communication
Engineering Journal, February 1995.