Get yourself a program that can convert files to OGG. I like Audacity because it also allows you to edit metadata, which will be very important and useful for our purposes. Also get yourself a program that can convert file extensions. I am using ReNamer.

Be careful when installing. You may be prompted to download unwanted programs, but these are completely optional.

Audacity[www.audacityteam.org]
ReNamer[www.den4b.com]

To start, you're going to want a music file. For my example, I am using "The Fated Showdown" from Raidou Kuzunoha vs The Soulless Army.

Start by opening Audacity. Then, drag your song into Audacity. There is some important information that you will need to fetch from the UI. First, look for the following:

Click on the cog in that box. Then, I want you to select "Start and End of Selection" if it is not already picked for you.


Next, I want you to click on the down arrows as shown here, and select "samples"


This is how we derive the numbers needed for some of the metadata we will need for our song. Press ctrl+A in Audacity, and the numbers from the box will have changed on the bottom. Make note of that, we will be using it momentarily.

To edit metadata, go to Edit on the top left of Audacity and select "Metadata Editor". Now that you're in there, add the following tags to the metadata of your chosen song;

• LoopStart
  
• LoopEnd
  
• Ver

Next, we're going to fill out some values for these newly created tags. In most cases, you can leave LoopStart at 0 unless there is a specific point where you want the beginning of the song's loop to start in game. For LoopEnd, use the numbers at the bottom from the "samples" box. For Ver, all files should use 0002.

Make sure the metadata is filled out correctly or your song will not play or loop at all in game.
Your newly edited metadata should look something like this:


Since I have specific points in mind where I want my song's loop to start and end, I used a value other than 0 for LoopStart. Try and experiment if you have an idea of where you want your song to loop.

Now, press Ctrl+Shift+E to export your file as an OGG file like so.


Last, locate that newly saved file for the ReNamer part.

Now, open ReNamer. We will be creating a new rule. To create a rule, press on the button that says "Add". Click on "Replace" on the left hand side, and make sure to fill out everything so that it looks like this:


Now press "add rule". Once that's done, ReNamer should look like this:


All that's left is to drag your OGG file into ReNamer and press the "Rename" button. Once that's done, locate the newly created sngw file.

Now, you will want to locate your MvC2 BGM. Mine was located in the following directory:
C:\Program Files (x86)\Steam\steamapps\common\MARVEL vs. CAPCOM Fighting Collection\nativeDX11x64\sound\bgm\mvc2\wav

Once located, there should be audio files that look like this:


If you want a backup of these, copy and paste them somewhere secure. For this example, the file s000.sngw is what I am replacing, which is the Airship theme. Remove s000.sngw from the wav folder. Then, drag your newly created sngw file into the wav folder and rename it to s000.sngw. If done correctly, you have replaced the Airship theme with your own custom OST. Be sure to launch the game and select the stage for training mode as Airship or Airship 2 to verify the song was successfully changed and that it loops properly.

Geronimo