I suggest VLC media player, really excellent, will run everything more or less out of the box, and has support for most of the more unusual codecs. Unfortunately/fortunately for Solaris there are no binaries, so you will have to compile yourself! Try this link:
http://www.videolan.org/vlc/
VLC is very good at playing all kinds of media, but not great with playlists for example. Have a go, see how you get on!
Best of luck!