The principle and structure of the decoding system are described and analyzed , the system uses a digital signal processor tms320vc5409 as a key device with a complex programmable logic device epm7128 , and use a usb chip according with usb1 . 1 protocol to communicate with the pc , it can decode the mp3 bitstreams realtime and output the digital audio by a speaker 重点介绍了mp3播放系统的原理与结构，该系统以一片通用定点数字信号处理器tms320vc5409为核心完成数据解码和控制功能，结合一片复杂可编程逻辑器件epm7128进行外围控制，并通过符合usb1 . 1标准的usb连接芯片与主机进行通讯，使其能够满足实时的mp3数据流存储，解码及数字音频的输出。
It comprises functions of video - audio data collecting , coding , storage , transmission , decoding , playback and vidicon remote control . the center can monitor many remote surveillance stations at the same time , and each remote surveillance station can monitor more than one singnal in the mean time 该系统具有视音频的采集、压缩、网络传输、解压、存储、回放、摄像机远程控制等功能，监控中心能同时监控多个现场监控站点，每个现场监控站点又可同时监控多路信号。
Because of taking digital technical in video and audio compressing and coding ; dtv take on a new look . it not only provide high definition video and high quality . . audio , but also provide muti - service . which made the user got the satisfied audio - visual feeling and satisfied service . dtv could make full usev of the present broadcast network . telecom network and computer network 数字电视被称为继黑白电视和彩色电视之后的第三代电视，由于它采用数字压缩编码技术处理视频、音频信号，使得电视广播以崭新的面貌出现，不仅提高了视频、音频的质量，而且提供了业务上的灵活性和多样性。
Second , this dissertation implements separately a mpeg - 2 video decoder and a dolby ac - 3 digital audio decoder based on software mode , and gives a audio & video synchronization algorithm based on audio - clock - benchmark in mpeg - 2 system decoder , whose feasibility and practicability have been proved by experimenting . it is an all - purpose algorithm , which can perform different decoder according to mpeg - 1 or mpeg - 2 system models , and can also be used for reference to the implementation of other multiplex stream decoders 然后，论文实现了基于软件方式的mpeg - 2标准视频及ac - 3格式压缩音频的实时解码与回放，并依据mpeg - 2系统解码模型实现了一种基于音频基准时钟的mpeg解码器的视音频同步算法，实验证明该算法可行、实用、通用性好，对符合mpeg - 1或mpeg - 2系统标准的视音频解码器均具适用性。
Recently , advances in postprocessing mechanisms have been studied to improve lip synchronization of head - and - shoulder video coding at a very low bit rate by using the knowledge of decoded audio in order to correct the positions of the lips of the speaker [ 3 . 36 ] , figure 3 . 2 shows an example of the block diagram of such a postprocessing operation 最近，对改善在很低比特率时头肩像视频编码的唇同步问题的后处理机制的研究已经取得进展，这种机制运用解码音频的知识校正讲话者的唇位，图3 . 2显示了一例这类后处理过程的框图。
In this paper , the decoding flow of ac - 3 is analyzed , moreover , optimization for software and hardware of decoding of audio . acs real - time decoding will be archieved with ip - based embedded risc core by adding special instructions , such as getbits , max , min and adding hardware for the operation of nop and the optimization of the program 本文分析了ac - 3音频的解码流程，并针对音频解码进行软硬件优化，对运用ip技术的嵌入式risc核，通过增加特殊指令getbits ， max和min ，以及增加硬件逻辑完成nop操作和解码程序的优化，实现了ac3音频的6声道的实时解码。
