I have created some .cfg files that allow you to use .ogg music. Or more accurately, I have edited the existing .cfg files for the .flac files to use the .ogg files compatible with the Vita port. I literally opened the .cfg files and changed all the .flac extensions to .ogg. Chocolate Doom does not seem to care if the SHA1 hashes are correct.
Create /data/chocolate/music/. Go to
Roland SC-55 Music Packs and download the .ogg packs for Doom, Doom 2 and Final Doom. You can also get the Hexen music pack
here. These archives will contain a folder called MUSIC. Rename this folder to either doom1-music, doom2-music, tnt-music, hexen-music, heretic-music or strife-music depending on the game and copy that folder to /data/chocolate/music/. Also copy the .cfg files from the attached archive into /data/chocolate/music.
You should end up with the following structure:
music/
----[gamename]-music/
--------<OGGs here>
----[gamename]-music.cfg
Now in the Chocolate Doom settings, switch the sound from OPL3 to Digital and enjoy glorious Roland SC-55 music.
EDIT - Some are reporting that the .cfg for Hexen in the attached pack doesn't work properly. Use the one from the above link instead.