在宽带网络大发展的时代,由于人们的需求不断提高,上网人数的不断增加,加之网络硬件设备的局限性,使得文件的大小成为网络传输和接收中的一个不可忽视的参数。一方面,人们越来越欢迎宽带网络带来的更直观、更丰富的新一代媒体信息的表现;另一方面,人们又不得不去面对视/音频文件传输时所耗费的大量时间。因为,多媒体文件要从网络服务器中下裁到用户PC的硬盘上,方能 In the era of great development of broadband networks, the increasing number of people accessing the Internet and the limitations of the network hardware make the size of the file an indispensable parameter in network transmission and reception. On the one hand, people are increasingly welcome the performance of a more intuitive and rich new generation of media information brought by broadband networks; on the other hand, people have to face a great deal of time spent on video / audio file transmission. Because, multimedia files from the network server down to the user’s PC hard drive, before