多媒体播放器（PMP）实现-电子与通信专业毕业论文.docx

多媒体播放器(PMP)实现
摘要
一个勿庸置疑的事实是,尽管PMP在中国市场已经发展了三四年,但一直到今天,整个行业的PMP普遍品质并未成熟。这一点与 MP3是有着鲜明的区别的,虽然MP3市场同样一直良莠不齐,但至少消费者拿到手中的产品是可以听歌的,但PMP却不然,消费者拿到手中的产品能否播放电影往往要打个问号。PMP还不够成熟主要表现有二,一是市面上充斥大量的u伪PMPⅣ,也即所谓的、、视频MP3", 此类产品本质上仍是MP3,但由于屏幕为彩屏,且稍大,就被厂商冒充PMP销售,事实上它仅能播放部分MTV片段,根本无法播放电影; 二是支持格式问题,这也是一直以来饱受消费者指责的核心问题之一,国内众多的PMP仅支持ASF流媒体格式,网络下载的多数电影需要转换格式方可播放,浪费大量时间人力。一般认为,一部PMP 至少要能支持DVD、VCD和MPEG-4中的两种格式才够用。
本论文回顾了PMP音频/视频解码的各种制式,比较了他们的优缺点。经过分析比较选用了SIGMA DESIGNS EM851 1方案来做多媒体播放器(PMP)的设计。本设计经过硬件整合,优化了电源管理电路, 实现了对D1(720*576)分辨率的各种视频源的流畅解码。视频解码支持:MPEG一1,MPEG一2 ******@ML,MPEG-4 ******@L5,Div—Video 1, and ,JPEG,音频解码支持:MP3,WMA,OGG,AC-3,WAV;采用 AU LCD数字显示屏,320xRGBx240分辨率;支持电视输出:复合视频/S端子,NTSC/PAL双制式;, 容量20’60G;留有CFI/II接口,支持HDD与CF之间双向数据交换, 可以实现数码伴侣的功能;,可以作为移动硬盘使用;采用免费的uCLinux嵌入式操作系统,提高系统的可维护性与可扩展性,方便日后增加新的功能。
关键词:PMP,音频解码,视频解码,MPEG
PORTABLE MEDIA PLAYER(PMP)DESIGN
AB STRACT
In PⅣ咿market in China has developed 3-4 years,but until today,the entire industry is not mature PⅣ咿universal quality.ⅣⅢ3 iS the the MP3 market has been equally varied,but at least consumers get their products can be the PMP are not, consumers Can get their products play movies often are not mature performance of two main,flooding the market First,a 1arge number of¨Ⅳ咿¨.the ”videoⅣm3¨nature of such products is still because of the color slightly larger, has been sell as PMP,in fact it only support some MTV it is impossible for movies;two support the is accused of consumers have
been suffering from one of the core domestic PMP only
support ASF streaming media works need to download the
maj ority of the film before broadcast format conversion,human waste a
lot of ,at least one PN口Can support and
Ⅳ format to be used both.
The Paper reviewed PMP audio/video decoding each kind of service pared with theirs their advantages and sel