BCSTM files incompatible with a 3DS · Issue #124 · Thealexbarney/VGAudio · GitHub
TUTORIAL] How to make normal Music Files (bcstm) for 3DS - mp3 to bcstm - YouTube
Looping Audio Converter Download: This tiny tool is designed as the frontend to other applications, and it converts the Wii-based BRSTM format, along with others, to MP3, WAV, OGG, and many more,