This paper describes processor-efficient implementation of a high quality MPEG-2 AAC encoder employing fast psycho-acoustic analysis, efficient encoding of side information, and SIMD instructions. A psycho-acoustic analysis in the MDCT domain reduces computational costs. Smoothing of scalefactors and optimized selection of Huffman tables are introduced to efficiently encode the side information. SIMD instructions are heavily used in MDCT and quantization processes to improve the encoding speed. Seven-grade comparison MOS test results show that the AAC encoder at 96 kbps/stereo achieves sound quality equivalent to that of MP3 at 128 kbps/stereo. The encoder works 13 times faster than realtime for stereo encoding on an 800 MHz Pentium III processor.
Authors:
Takamizawa, Yuichiro; Nomura, Toshiyuki
Affiliation:
NEC Corporation, Kawasaki, Kanagawa, Japan
AES Convention:
110 (May 2001)
Paper Number:
5294
Publication Date:
May 1, 2001
Subject:
Low-Bit Rate Audio Coding
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