一种软硬件协同的WMA解码器的设计

A Hardware-software Codesign for WMA Decoder

WMA是微软公司提出的一种音频标准,其压缩率达到MP3格式的2倍,而且高频保存的效果超越MP3。重点阐述WMA软硬件设计方法,简单介绍WMA解码流程,由于纯软件WMA解码需要的CPU负荷太高,而且功耗比较大,不适合便携式播放,采用ARM7加硬件的模式,整个系统工作频率为60MHz,软件部分完成格式解析和解码过程控制,硬件部分完成比特读取、游程解码和DCT-IV部分的计算,硬件采用门控时钟的方法来减低功耗。采用该软硬件协调的实现方法,不仅能够解决功耗和解码兼容性的问题,而且能达到根据不同用户需求来修改应用程序的目的。

WMA is an audio standard proposed by Microsoft .Its compression rate is 2 times higher than the MP3 format , and it is stored in the higher frequency effect than MP 3 .This paper focuses on the hardware -soft-ware codesign methods for WMA decoding and WMA decoding process is briefly introduced .A pure software WMA decoding requires high CPU load and power consumption , which is not suitable for portable players .For example , in ARM7 plus hardware mode , the entire system works at the frequency of 60MHz, in which the soft-ware part is in charge of format parsing and decoding process control , and the hardware part complete the bit read, decoding and calculating DCT -IV parts.The hardware uses the clock gating method to reduce power consumption .Coordinated implementation of hardware and software can not only solve the problem of power and decoding compatibility , but also meet the needs of different users to achieve the purpose of easy -modification on application programs .