Design and VLSI Implementation of Low Complexity MDCT-based Psychoacoustic-Model Co-Processor for MPEG-2/4 AAC Encoder

• Main Authors: Jia-Her Luo, 羅嘉和
• Other Authors: Tsung-Han Tsai
• Format: Others
• Language: zh-TW
• Published: 2006
• Online Access: http://ndltd.ncl.edu.tw/handle/25004859094498462188

碩士 === 國立中央大學 === 電機工程研究所 === 94 === Audio technology is an important part in our life. Everyday, people listen to their favorite songs from broadcast、iPod、cellular phone…etc. After the MP3 very popular in the world, the MPEG organization proposed MPEG-2/4 AAC to be the next generation audio standard. In this thesis, we will present the key component design for MPEG-2/4 encoder of the portable device. Psychoacoustic Model (PAM) as the key component in the MPEG-2/4 AAC encoder. It occupies the heavy computation load in AAC encoder and makes the AAC encoder hard to be implemented on the portable device under the real-time and low power condition. In order to overcome the above described problem, we proposed a dedicated co-processor design to speedup computation of the PAM. In algorithm level, the MDCT-based PAM、the look-up table of the spreading function ,the log-scale table of the Threshold Generator (TG) calculation are adopt to this design. Besides, logarithmic based Quantization Loop (Q Loop) algorithm is proposed to solve the scale and complexity computation problem between PAM and Q Loop. In architecture level, the pipelined MDCT and DSP-like architecture are proposed for the high efficient and low complexity consideration, respectively. The proposed PAM architecture is implemented in the TSMC 0.18 CMOS technology, total gate count is 28349. The proposed architecture can encoding stereo content with the DSP or the RISC, whose MOPS below 7 MOPS at sampling rate 44.1k and bitrate 128kbit/s.