What is this?
Branches are spawned from trunk (or other branch) in order to concentrate on stabilizing the tree for release or to start implementing long-term (possibly throw away) changes that would disturb development in trunk. CVS and other version control systems use the word HEAD instead of trunk
See #6128 (Port MythMusic to Qt4)
The point of the mythtv-vid branch is to fix some of the long standing deficiencies in the video output classes
This branch contains backported fixes for the currently released version of MythTV.
These branches haven't been updated in two or more years.