Implementation And Optimization Of DRA Audio Docoder Based On Android

DRA audio codec technology is China’s national audio codec standard. DRA usestransient-localized MDCT and statistic-adaptive codebook assignment technology. It hasadvantages of high fidelity, high compression rate and low decoding complexity. Theindustrialization of DRA, though being very promising in near future, is now still in an earlymarket cultivation stage.This paper mainly focuses on the implementation and optimization of DRA audiodecoder on Android operating system. As the mainstream open operating system, Android hasbeen applied to mobile phones, tablets, smart TV and so on. In November2012, the statisticsshowed that Android system had occupied76%of the global smartphone operating system,and had90%of the smartphone operating system in our country, thoroughly occupied thesmartphone market in China, and became the world’s most popular smartphone operatingsystem. Therefore, the future development of DRA industry would rely significantly on theAndroid market share.This thesis digs deep into the DRA audio codec standard. Below are the main efforts:First and foremost, the implementation of DRA decoder is elaborated. As with DRAdecoding algorithm, binary tree search method is proposed for Huffman decoding, meanwhile,FFT is used to implement IMDCT transform algorithmso as to optimize DRA decodingalgorithm. Based on both optimizing algorithm, the detailed solution of DRA decoderimplementation is put forward.Secondly, this thesis proposed several DRA decoding optimization method. Forplatforms with no float-point unit, fixed point would be used in order to enhance thecompatibility of the decoder. Moreover, NEONmultimedia instruction setsis adapted, thusgreatly improve DRA decoding efficiency.The study of implementation and optimization of DRA audio decoder on Androidoperating system is believed to have remarkable positive impact to future growth of DRAindustry.