System Design & Algorithm Research Of Audio Encoding & Decoding Based On DSP

MPEG (Moving Picture Experts Group) is a workgroup of ISO/IEC responsible for proposing the technology standard of moving pictures, audio and the compression (abstraction) and extraction of their combination. MPEG-1 layer3 (mp3), which has the high compression ratio, good restoring quality for voice and immediate complexity, is the third layer encoding-decoding algorithm of the internal audio standard (ISO/ICE 11172). MP3 music made based on this standard is widely used in the fields of digital audio restoration and media audio-video transmission in Internet.Based on the above background, through researching and analyzing we proposed the research topic based on the design and algorithm of audio encoding-decoding system. The purpose of this topic is: completing the design and realization of the whole system's hardware plane mainly refers to the all-purpose DSP chip of TI Company's C5000 series-TMS320VC5402, researching on mp3's encoding-decoding algorithm and the DSP realization on its hardware plane. The whole system's plane includes minimum system of DSP, FLASH storage, audio CODEC and USB communication, etc. The system downloads the data stream of MP3 format through the communication between USB interface and PC, stores them in FLASH and then read the MP3 data stream in Flash by DSP, finishes decoding and plays with CODEC. Moreover, the system can also program for the other encoding-decoding algorithms for DSP, realizes the audio encoding-decoding for various format of data stream and has a very good flexibility for updating soft.The work of the whole topic has done includes the following. Firstly, according to the design of theory diagram and PCB and the processing of making PCB to the main chip and the welding of other devices, finishes the design and realization of hardware plane for MP3 decoding system, and introduces in detail about the hardware debugging method for every model in the hardware plane, illuminates the problems that easily comes across and displays some part of the debugging program;Secondly, analyses and does researches for the basic principle of the process for encoding-decoding mp3;we focus on the decoding algorithm for MP3, improve andoptimize the Huffman decoding model and the IMDCT changing model. From the simulation on PC to the programming realization on DSP chip, we debug for both and software and hardware in the DSP assemble developing environment of CCS2.0 by TI company and complete the design and realization of MP3 decoding algorithm base on the DSP.