| dc.description.abstract | Since MP3 has been published, and became popular consumer applications, the digital audio technique is an important part in daily life. The applications of digital audio technique include broadcast system (DAB/DAB+), portable players, iPod, and mobile phone …etc. Organization of Moving Picture Experts Group (MPEG) proposed MPEG-2/4 AAC standard which is the audio encoding technique of next generation. Both the performance and compression ratio of AAC are better than MP3. However, the algorithm is more complex and computation-intensive. Hence, how to reduce the computation and maintain quality is a major challenge of AAC encoder.
In this thesis, we optimize the key component in MPEG-2/4 AAC encoder, which is psychoacoustic model (PAM). PAM has different complicated functions to model the human auditory system. This work exploits several methods to achieve low cost consideration, which are memory-based architecture for filterbank, DSP-oriented threshold generator, shared memory, and coefficient merged scheme. We use fully pipelined MDCT and fast algorithm for filterbank to improve performance. Moreover, we apply cache-register, clock-gating, operand isolation, and multi-Vth cell to save power consumption. As the synthesis result, our PAM consumes 43 k gate counts in TSMC 0.13 COMS technology, 3.1MHz operation frequency, 3.69mW for AAC encoder. Meanwhile, we also integrate our design into a SOC platform and perform the verification on the platform. | en_US |