TL;DR - YOU CAN MAKE GBA MUSIC WITH MIDI BUT IT’S WEIRD AND TIED INTO A SPECIFIC GAME SO IT MIGHT BE HARD TO ALLOW ON BOTB

I want to call to attention 2 things I noticed with the beloved new GBA format. For one, all the tools listed on the lyceum page were trackers or sequencers (that’s fine in and of itself, you get what you get with these things sometimes). But the second thing stands in contrast to that; from what I know, the Fire Emblem hacking community primarily uses MIDI to create GBA songs. They have a tutorial listed here: FE GBA Music for Beginners

My main question is this: is there a way we could open this up as a means of submitting GBA music, to facilitate people who prefer MIDI over trackers?

The reason I ask is because of the issues that are involved. Based on this guide, it seems like the only unique filetypes generated for GBA insertion are .s files, which aren’t mentioned in the submittable formats, and it sounds like to playback the audio you would need to use either a tool specifically for FE hacking, or insert the song into the game, the latter of which feels pretty out of the scope of BotB. I also don’t know if it’s just as simple as converting the .s file straight into a .gba file somehow, or if there’s a nicer solution that avoids this mess.

Point is, I think it would be great to allow this MIDI method of GBA music creation that a lot of people use, but I don’t know how one would make it work with BotB’s rules on playback for submissions and what can be converted to what. I would like to hear others’ input if they know some stuff I don’t, since I’m at a loss here.

Allowing .s would be generally favourable to having a FE gba file with the music injected, just because of the copyright issues

Well here is probably the biggest issue when making music with the GBA. From what I see in the tutorial, Fire Emblem was developed using the m4a sound engine (aka Sappy). It was probably the most used sound engine to make commercial GBA games and it works with midi files indeed! The problem is that like most of the sound engines used for commercial games, m4a is not publicly available... That's why your only choice if you want to work with midi is probably to rely on hacking tools.

I'm a complete noob regarding ROM hacking but it seems to be a way to play music on the GBA indeed. If someone is effectively able to make a GBA song this way, I agree it would be good to update the gba (format) page, providing detailed instructions explaining how to produce a .s file (if that's the format you want to use) from your midi song.

I never tried it but I think I saw a bunch of similar tutorial to hack Pokémon ROMs (the GBA Pokémon games also used the m4a sound engine), maybe this could help too! In addition, this page

is good if you want to learn more about the different GBA sound engines that were used in commercial games.

Also just a newbie question, I understand ROM hacking lets you use custom music in your modified version of the game. However, is it also possible to play a song right when the game starts or are you obligated to replace a certain song in the game and play a part of the game when the original song is played in order to hear your composition?

Oh cool, I couldn't find much on this!

I wanted to gather more info, but I'm going to share here since it is related. The .s files you mention can be used to inject the song into any game rom that uses the Sappy engine (from the Nintendo SDK). So it's not just limited to Fire Emblem, but many other titles.

Through some other tools, the music can be extracted and converted to .gba. On paper all you need for making GBA music with midi is:

- A midi editor: to write your track.
- A soundfont player: to send midi to while writing.
- gba-mus-riper: to extract your soundbank into a soundfont.
- Mid2Agb: to convert your track to an injectable format.
- Sappy 2006 mod 15: to inject your track inside an existing rom. https://www.youtube.com/watch?v=NfitdOWcEV8
- saptapper: to extract your track into independent .gsf and .gsflib files.
- gsf2rom: to make your track playable on hardware. https://hydrogenaud.io/index.php?PHPSESSID=oal12bqgl0c0815ttu4ljotc7o&topic=99038.msg957919#msg957919

The Sappy tool in question supports custom samples, GB instruments and ch3 waveforms (no macros or tables unfortunately).

I did a little test, and I managed to confirm this works, but I'm not sure I will able to write an article for the lyceum before oops ends.

So what I’m hearing is that .s can be converted to a .gba for listening purposes? That might make it a ton more viable to add it as a submission type, or even if it doesn’t get added, be able to use MIDI to get to .gba, which is submittable.

sounds like a viable path to victory as long as there's no copyrighted content from the game ROM portion of this process involved in the eventual .gba file that gets submitted as the entry. which i would want to be really sure of, considering how litigious they are.

thanks for all this really cool research into the format. it's neat to see all these things being uncovered, especially since gba music is very underexplored. it's convoluted, but as long as there's some instructions it seems very doable!

Although I'm not really qualified to speak about the legality of it, technically I believe the .gsf files themselves are an equivalent of .vgm for GBA. So those should be fine.

Someone better informed should look into the source of psflib

and gsf2rom

to be safe.

If it turns out there is an issue, maybe .gsf could be added as an accepted file format. Actually probably .zip instead, since .gsf and .gsflib files need to be together for the conversion to work.