解决fedora20 播放mp4文件缺少h.264问题，使fedora20播放mp4，avi等格式。
安装rpmfusion源：
su -c 'yum localinstall --nogpgcheck http://mirrors.163.com/rpmfusion/free/fedora/rpmfusion-free-release-stable.noarch.rpm http://mirrors.163.com/rpmfusion/nonfree/fedora/rpmfusion-nonfree-release-stable.noarch.rpm'
安装视频解码器（针对64位系统，如果你的是32为，把下面的x86_64替换成i686）：
sudo yum install gstreamer-plugins-good gstreamer-plugins-bad gstreamer-plugins-ugly libtunepimp-extras-freeworld xine-lib-extras-freeworld
sudo yum install ffmpeg ffmpeg-libs gstreamer-ffmpeg libmatroska xvidcore
sudo yum install gstreamer1-plugins-bad-free-extras.x86_64 gstreamer1-plugins-base-tools.x86_64 gstreamer1-plugins-ugly.x86_64 gstreamer1-plugins-bad-freeworld.x86_64 gstreamer1-libav.x86_64
ok！
Fedora 22怎么播放rmvb mp4 mkv视频文件：http://www.linuxdiyf.com/linux/12388.html
Ubuntu播放AVI与MP3影音文件：http://www.linuxdiyf.com/linux/11258.html