I asked only because I got the impression you have to use a prog to extract the contents of one of the main vp files (whereby you can access the mediavp directory), then recompile the vp files with the patches to complete the process...
Having read the FAQ, it seems all i have to do is create a mediavps folder and dump them in there. That done, I see no visible changes to the desired effect.
The name of the folder is irrelevant. With a launcher flag (-MOD Dir1,Dir2,...,Dir_n) you set the subdirs within Freespace2 folder where the program looks for files. So, firstly, it looks in Dir1 then in Dir2 and so on and at the end it looks in the main FS2 folder (if you dont type a -MOD flag, it only looks in this folder).
Within any of these folders, FS_Open.exe firstly looks for files in \data subfolder structure (i.e. individual not vp-contained files). Don't worry very much about this structure but if you want to know more you can read (
http://www.hard-light.net/forums/index.php/topic,39114.0.html). After \data, it starts looking inside vps in alphabetical order so it will look in aaa.vp previously to bbb.vp. (Vps also contain a \data structure).
When it finds a needed file in aaa.vp it stops searching, so it doesn't matter how this file is in bbb.vp. (This is the reason to make SCP vp additions to be called mv_*.vp, as the first retail vp is root_fs2.vp. In this way if you have a better Texture.jpg in mv_textures.vp it will override the old retail one, and of course aaa.vp files will override mv_*.vp ones)
When you set up the MOD tab, you are really 'typing' a -MOD flag, (look at it in Features Tab upper command line). What the Launcher does is setting:
-MOD List of subdirectories in PrimaryList, Selected subdir in the MOD tab, List of subdirectories in SecondaryList
where PrimaryList or SecondaryList are read from the mod.ini file you type as plain text inside the Mod Dir as explained in FAQ. But the used names for directories are really irrelevant. If there's no mod.ini or this mod.ini hasn't got these entries, Launcher only sets
-MOD Selected subdir in the MOD tab.
So, the best way to install mediavps is copying them all in its own subfolder (call it as you want but 'mediavps' can be a good and clear name), and then make FSOpen use it through the MOD tab, (so their improvements or changes will override retail fs2 files). Then If you install a 'real' mod and you want to make this mod use media vps too, make a folder for it, (use any name you want), select that folder within Launcher MOD Tab and create a mod.ini file inside the Mod folder to point to 'mediavps' folder through SecondaryList entry. You can swap between mods with the MOD tab.
To add any patch to mediavps, copy its vp in 'mediavps' and be sure it has a name BEFORE mv_*.*