You will need at least one system that's online to do anything like that. Google "yum offline" for a list of methods.
Some packages can be installed via .rpm files. but you will need all the dependencies and that could be a major headache for a complex package like vlc.
Look at the
vlc how to for installing vlc.
.rpm repositories are also available. I've used
pbone repository before to download .rpm files. (but don't take that as an endorsement of that site.)
