Hello everyone.
I am trying to make an mp3 song compatible with FE Builder. The issue is, obviously that you can’t import mp3s. I also don’t want to use .wav files because of the space they take.
I can’t find any MIDIs for the song I’m trying to make. Is there an editor or a software I can use?
I’ve tried Anvil Studio but it won’t let me since it is past a minute in length.
Any help would be great, thx 
The GBA is not an MP3 player. You’re not going to have much luck using it like one. This is an infeasible and bad idea. Using a .wav would “work”, but as you stated, it takes up a lot of space in the ROM, and usually doesn’t sound very good anyways. If you can’t find a MIDI, you’re better off finding an alternative track that does have a MIDI you can use.
Depending on what kind of midi you’re looking for, you’re either going to need to extract the original from the game itself which can be done using music converters like VGMTrans (this only works with roms/ISOs for certain game systems like GBA, DS, PS1) or look around sites like VGMusic for already extracted midis and arrangements done by people who know how to make them from scratch. If the song you want doesn’t have an original midi file, your options are either finding an arrangement, making one from scratch, or not using the song at all.
Yeah, I like using Sekaijuu. Give that one a whirl.