This has been up on my site for a long time. I still see people asking over music in threads and such, so here it is, my music editing tutorial. I tried to go in to as much depth as possible, rather than the sketchy outlines people have been given.
Music editing, some see this as a hard thing in hacking, personally, I disagree. Sappy is currently the only way to edit music. For some reason when you hit “assemble that ugly thing” there’s a good chance it won’t work. (I'm not sure if this applys to newer versions of Sappy, that have been released since I wrote this, but the tutorial still applies). From experimenting, I don’t think sappy writes the voice group properly sometimes. I can’t confirm this; it’s just a theory. There is a way to overcome this problem; this means you can insert any midi, without failure if you follow my instructions carefully, which I shall write below.
To edit music you need the following things:-
First place EVERYTHING in the same folder, if you don’t this’ll get confusing. To convert your midi, drag it onto “midi2agb.exe” If your midi is called “FutabaTown.midi” it will become “FutabaTown.s”. A very easy first step.
Converting your single .s file into multiple .s files
Most people just insert that single .s file, however that tends not to work. So we’re going to convert it into separate ones for each instrument.
To do this you need to sacrifice a ROM, so just copy one, or get an unedited one. Now open up sappy. Find any town, it doesn’t really matter on this. Click import and copy the voicegroup. Now, go to “Assemble Song” click on the .s file we created earlier. Paste the voicegroup into that section, also set the base destination offset to a blank space, so &H800000 if you’ve not already used it. Now click “Assemble that ugly thing!” and wait, click yes to the prompt that appears after a while. Then close that window. Now you need to reload sappy and the ROM that you just edited that you’re sacrificing. Find the town that you edited and click export. Now, tick all the boxes.
Don’t get confused with this next bit; it’s not that difficult.
In the right hand box either type $T or $P. $T numbers the tracks your exporting and $P labels the tracks with an offset. I suggest $T, it doesn’t really matter. Click ok.
Now we finally get to insert your freshly prepared music. Open your REAL ROM (Not the one you sacrificed!). Find the town that you want to write the music to. Go to import. You should see numbered files, or offsets, depending on what you chose earlier. Tick all the numbered/offseted files.
Before we carry on we need to look for blank space in a hex editor, so open one up and look for A LOT of “FF FF FF FF FF…” take a note of the offset on the right.
Back to sappy, enter this offset in the second box down, this “repoints” the track so it doesn’t overwrite data. No click ok and press yes at the prompt. You’re done! Music inserted! Now try it in the game. If it sounds odd go back to where we’re inserting multiple tracks and change the voicegroup box to one of another track (which can be viewed if you click on the town/route and press import, just copy and paste it), This changes the instruments. You can change the instruments by hex, but most of the time, it’s not necessary, good luck everyone!
~by Green Charizard