Pokémon D/P/Pt OSTs with Pokémon Emerald Soundfont

1. INTRODUCTION

This post explains the process for creating in-game playable covers of Pokémon D/P/Pt OSTs using the Pokémon Emerald Soundfont.

I have a disclaimer: this “project” should not be intended as a “good sounding” Pokémon Emerald version of other video game OSTs.
Indeed, the purpose of these music covers is to actually make those OSTs playable in a GBA game.
Compared to most videos of video game OSTs remade with a different soundfont, my videos feature a recording of the said OST playing in a GBA game. Specifically, a simple GBA music player I made (heavily inspired by Butano examples).
Secondly, the idea was also to show how instruments from the original Pokémon D/P/Pt Soundfont and the Pokémon Emerald one change.

 

 

2. WORKFLOW

The workflow of creating a cover is quite straightforward. I used OpenMPT to work on the MIDI files, converting them into the Impulse Tracker format (.it). This is only one of the Tracker formats that are compatible with Butano, but among those, this one seems to be the most advanced.
Apparently, converting a MIDI file to an Impulse Tracker one sometimes also changes the tempo, but this was an issue I’ll address later.
At this point, I simply added the final file to my simple GBA project code and compiled it into a .gba ROM.

2.1 INSTRUMENTS
As I explained previously, I intended to show how different the original and the Pokémon Emerald soundfont sound. To do so, I simply switched the mapped instruments in the MIDI with the ones in the Pokémon Emerald soundfont.

Of course, this wasn’t always so easy, because some instruments from the original Soundfont weren’t available in the Pokémon Emerald Soundfont. I had to trust my ears and choose the best-suited instruments.

There’s a side note for the drumkits. I noticed that the MIDI files have many different drum kit instruments compared to the Pokémon Emerald Soundfont. In this case, I decided to explore one of the drumkit instruments in the Pokémon Emerald soundfont, extract the samples, and use them where I felt they were best fitting.

2.2 TEMPO

As I mentioned above, the conversion from MIDI to Tracker format implies a tempo change. I learnt that Trackers have both tempo (for .it files, the maximum tempo is 255 bpm) and ticks per row. This measure represents the number of lines the tracker plays, and it’s normally set to 6.
Usually, the converted songs were way slower than the original ones at 255 bpm. Lowering the ticks per row setting partially solved the issue: the song was surely playing at the right tempo, but some notes were getting chopped, and the song effects were all messed up.

The definitive way to solve this, although not elegant, was to simply keep the tempo at 255 bpm and 6 ticks per row, then import the .it file into my GBA music player, and work on the code to adjust the tempo.
As I explained in my previous post, some commands in Butano allow tempo change. I changed the values until I found one that felt closest to the original tempo.
So, once again, I’m trusting my ears. Because of that, there will be some margin of error lol.

2.3 OTHER ISSUES

I decided to work on the songs in alphabetical order. However, I am not promising this order will be kept for the video publishing. The reason is that I had some issues with certain songs. No real surprise if we consider that most of those songs were also some of the most complex in the games. Among those are Cynthia’s and Giratina’s battle themes.
Since I am very busy these days, I don’t expect to find any time to work on fixing said issue. I’ll keep everything updated, though.

 

 

3. CONCLUSION

The final result can vary a lot: some songs sound nice, some don’t, the loops are quite a mess as well (so I decided to record the song only once), some instruments and the tempo could not be exactly on point, and, finally, some songs couldn’t be played.
Hopefully improving, it’s still really interesting how many OSTs sound very similar between Pokémon D/P/Pt and Pokémon Emerald. It’s also very cool to see those OSTs being played in a GBA “game”.