'kmplayer' comes with no codecs at all.
Required : libdvdread , libdvdcss. ( libdvdread is probably already installed ? )
'libdvdcss' is in the remi.repo
http://rpms.famillecollet.com/
Please download
http://rpms.famillecollet.com/remi-release-12.rpm
# rpm -Uvh remi-release-12.rpm
# gedit /etc/yum.repos.d/remi.repo
..... and edit the first "enable=0" entry to enable=1
( Not the testing.)
# yum install libdvdread libdvdcss
..... And I guess you can watch video.
.