关于linux下流媒体播放的问题

我用的是红旗6sp1，上红旗官网可以看上面的新闻视频，不过一把浏览器最小化就重启，很郁闷。于是就下了个realplayer11 for linux，但是却弹出对话框，说是未知文件类型(The file contains an unsupported video format. The needed codec is not installed on your system. (This clip contains Windows Media Video 8, which is currently unsupported.))。这是为什么啊？