Awesome

GSM Player

In mid-2004, I ported the GSM RPE-LTP (also called GSM Full Rate) audio codec, which has been used in mobile phones, to the Game Boy Advance. Now you can use your GBA as a portable music player, with up to 150 minutes of Good Sounding Music on a 256 Mbit flash cart.

From mid-2004 to mid-2019, GSM Player for GBA went unmaintained, and changes to popular GBA homebrew toolchains rendered it unbuildable. This repository ports the application to a more recent version of devkitARM.

Building a ROM

If building from source:

make build/allnewgsm-bare_mb.gba
padbin 256 build/allnewgsm-bare_mb.gba

Convert audio files to GSM at 18157 Hz (a nonstandard rate; see docs/lying_to_sox.txt for how to force this in SoX and FFmpeg)
Pack them into a single GBFS file using gbfs included with devkitARM tools: gbfs gsmsongs.gbfs *.gsm
Concatenate the player and the songs.
- On Windows: copy /b build\allnewgsm-bare_mb.gba+gsmsongs.gbfs allnewgsm.gba
- On UNIX: cat build/allnewgsm-bare_mb.gba gsmsongs.gbfs > allnewgsm.gba

Controls

To control the player:

Left: Previous track
Right: Next track
L: Seek backward
R: Seek forward
Select: Lock other keys
Start: Pause or resume