Implementation Of MPEG-4 AACplus Decoder Based On MIPS

In recent years, with the development of modern communication technique, the need and desire of people for multimedia operation is more and more increasing. The consumers are asking for more and better audio productions and services. As is known to all, being digital is one of the most obvious characters of the present society. During the process of the society becoming digital, digital audio, a good method of the storage, processing and transmission of high fidelity audio signal, has been widely used in the area of consumption electronics and professional audio etc.Associating with the development of digital audio process technology, many kinds of multimedia data compression coding standard are also improved. The development of audio compression coding technology is always got in the conflict between the lowering data ratio and the audio quality. At present, MPEG-4 is one of the most important and powerful multimedia compression coding international standards. As the most newly developed MPEG-4 audio technology, MPEG-4 AACplus v2 gives a wonderful resolution to the low data ratio, high quality audio compression area, which represents the new trend of the development of multimedia audio compression standard in the near future.In this thesis, we analyze the necessity and feasibility of audio compression. Also, the constitution of MPEG-4 audio series standards and their technical background are introduced. Then, we give a detailed description of MPEG-4 AACplus v2 on the characteristic, system component, standardization, demonstration application and the independent quality evaluation.This thesis takes the MPEG-4 AACplus v2 decoder as instance, firstly discusses the key technology of MPEG-4 AACplus v2 compression coding standard and gives a deep and clear analysis to the main decoding module, especially to the two newly developed modules, that is Spectral Band Replication module and Parametric Stereo module comparing to the MPEG-4 AAC standard. In addition, we give a clear picture of the relation and difference among the three MPEG-4 audio compression standards, which are AAC,AACplus v1 and AACplus v2. On the basis of the above discussion, this thesis makes some improvement and optimization to the propositional coding algorithms by MPEG-4 AACplus v2.As is known to all, the selection of the processor is vitally important for the implement of the audio decoder. In the fourth chapter, this thesis gives a brief introduction of the basic instruction and system frame of the MIPS processor HSB-1101. In order to cooperating with the development of the multimedia video and audio signal, we briefly introduced the Media Player project based on the HSB-1101. And then, given the features of the development platform, we give some analysis of the functions and running figures of the major audio decoding modules, and also come up with some optimization methods of the MPEG-4 AACplus v2 decoder.At the end of the thesis, we give the results of the MPEG-4 AACplus v2 decoder based on the MIPS processor and make a comparison with the standard float point decoder on the decoding quality. Also, under the precondition of guaranteeing the decoding quality, this thesis makes a analysis of the decoding speed and the real-time feature.