[Audio] Mass insertion of music?

[jespoke]

I made a video of the entire Emerald soundtrack with just trumpets for Youtube: https://youtu.be/5Vf1G3vUJ5g
So now i have the whole soundtrack, sound effects and FR/LG soundtrack and all, as all trumpet midis with the route 110 soundfont. And that got me thinking if there was any good way of putting them all back into my Emerald rom. There are 529 files, so doing it one at a time seems like it would take a longass time...

 

[duckdavis]

I wonder if there's a way to just replace the instruments themselves, and not the songs. Probably would be way easier.

 

[RoadToCerulean]

In fact, you don't have to export the songs to MIDIs at all.

From Songs 350 to 558 (the songs in the sappy.xml), their tracks and headers take up a continuous chunk of space, from 0x8903A8C to 0x89A2A19. So:

Spoiler:

1. If you want to replace all instruments to the trumpet (numbered 56 or 0x38), search for all "BD"s in this range and replace the next bytes with "38", hence all instrument controller events are set to BD 38 which stand for the trumpet (but BEWARE NOT to overwrite header pointers). Just don't understand why you're obsessed with trumpets.

2. If you want to replace all voicegroups to Route 110's (0x8677318), then search "00 00 B2" in this range and notice the next 4 bytes. Replace them all with 18 73 67 08.

Explanation: The header in a GBA ROM is made up of these components:

AA 00 00 B2 [Pointer to Voicegroup] [Pointer to Track 1] [Pointer to Track 2] ...

Where AA stands for the numbers of tracks. It usually ranges from 01 to 0A but can be at most 10 when the track limit is expanded to 16.