适用平台：Fedora 8 64位系统
故障原因:yum方式安装了mplayer。下载了all-codecs解码包，解压到readme中所说的/usr/local/lib/codecs/目录仍然不能播放rmvb。只有声音没有图像，提示Cannot find codec matching selected -vo and video format 0x30345652。其实mplayer官方的解码包名称模糊，all-codecs并不含有rmvb解码所需的全部解码器。另外由于非源码安装的mplayer路径并不是/usr/local/lib/codecs/。
解决方法:正确安装适用64位系统的解码器
解决步骤:
1、从http://www.mplayerhq.hu/MPlayer/releases/codecs/下载下面四个文件
all-20071007.tar.bz2
essential-amd64-20071007.tar.bz2
windows-all-20071007.zip
windows-essential-20071007.zip
2、在命令行模式下用mplayer播放一个rmvb格式的文件，注意查看出错信息，看mplayer是从哪儿读取的插件。
我的出错信息如下
Opening video decoder: [realvid] RealVideo decoder
Error: /usr/lib64/codecs/drvc.so:
cannot open shared object file: No such file or directory
ERROR: Could not open required DirectShow codec drvc.so.
Read the RealVideo section of the DOCS!
VDecoder init failed :(
Opening video decoder: [realvid] RealVideo decoder
ERROR: Could not open required DirectShow codec drvc.dll.
Read the RealVideo section of the DOCS!
VDecoder init failed :(
Opening video decoder: [realvid] RealVideo decoder
Error: /usr/lib64/codecs/drv4.so.6.0:
cannot open shared object file: No such file or directory
ERROR: Could not open required DirectShow codec drv4.so.6.0.
Read the RealVideo section of the DOCS!
VDecoder init failed :(
Opening video decoder: [realvid] RealVideo decoder
ERROR: Could not open required DirectShow codec drv43260.dll.
Read the RealVideo section of the DOCS!
VDecoder init failed :(
Opening video decoder: [realvid] RealVideo decoder
Error: /usr/lib64/codecs/drvc.bundle/Contents/MacOS/drvc:
cannot open shared object file: No such file or directory
ERROR: Could not open required DirectShow codec drvc.bundle/Contents/MacOS/drvc.
Read the RealVideo section of the DOCS!
VDecoder init failed :(
Cannot find codec matching selected -vo and video format 0x30345652.
Read DOCS/HTML/en/codecs.html!
所以我的mplayer解码目录是/usr/lib64/codecs
3、将上述4个文件解压到你自己的mplayer提示目录即可（例如，我的系统就将4个文件解压到/usr/lib64/codecs目录）。
注意事项：
1、实际上播放rmvb只要几个文件，将所有的解码器放在一起是防止播放其他文件出现类似问题。
2、所有的文件直接在codecs目录下，而不是在codecs/all-20071007等类似目录下。