A version control is very important as it keep track of computer programs.In this archive the files of the source code of computer programs are kept.It also gives access to track changes made to the source code, why the change was made, who made the change, gives reference about issues that were solved and improvements that occurred with the changes.
http://oss-watch.ac.uk/resources/versioncontrol
Patch is basically making new changes to a software fixing bugs or adding documentations to it. They are mostly used to submit contributions to projects, but however it is the project manager that chooses whether to apply the changes to the source code.
http://oss-watch.ac.uk/resources/softwarepatch
Most of Vlc repositories uses Apache Subversion as their version control system. Subversion is an Open Source Software Founded in the year 2000 by Collabnet Inc.
https://wiki.videolan.org/Subversion
Other System controls are: Git, SVN, Mercurial and CVS