Guide
What is a BRSTM file?
.brstm file and your usual player has no idea what to do with it, nothing is broken: it is the music format of Wii games, designed so a theme can play forever. Here is what it is, how it works inside and how to listen to it.Updated October 18, 2026
BRSTM in a nutshell
BRSTM (Binary Revolution STreaM) is the streaming audio format Nintendo used on the Wii for game music. "Revolution" was the console's codename before launch, hence the "R". Files use the .brstm extension and always start with the RSTM signature.
A BRSTM stores two things: the audio, usually compressed, and the information needed to loop it. That second part is what makes it special and what regular music formats (MP3, AAC, WAV) lack.
Beyond Wii games themselves, the modding community has used BRSTM for years to put custom music into games such as Super Smash Bros. Brawl and Mario Kart Wii, so today there are BRSTM files of soundtracks from many consoles.
The secret: loop points
Game music cannot know how long you will take to finish a level. So it is not written to last three minutes and end, but to repeat without you noticing. A BRSTM is split into two parts:
- Intro: the start of the theme, which plays only once.
- Loop: the rest, which repeats indefinitely. When playback reaches the end of the file, it jumps back to the loop start and carries on with no pause.
The file stores the exact point (in samples) where the loop begins; the loop end is the end of the audio. If the point is well chosen, the jump is inaudible and the theme can play for hours as if it were a single piece. If it is badly placed, you hear a jump or a click on every pass.
Some BRSTM files have no loop: they play once and end, like a regular song. They are used for fanfares, endings or themes that do not repeat in the game.
What is inside a .brstm file
Inside, a BRSTM is a binary container with a header and three chunks. You do not need to know this to listen to one, but it helps explain why some files cause trouble:
| Chunk | What it contains |
|---|---|
RSTM header | The format signature, byte order, total size and where each chunk starts. |
HEAD | The audio details: codec, sample rate, channel count, whether it loops and where, total number of samples and how channels are grouped into tracks. |
ADPC | A table with the decoder state at the start of each audio block, so playback can start anywhere (and jump back to the loop start) without decoding everything before it. |
DATA | The audio itself, cut into blocks (usually 8 KB) that alternate between channels. |
If a file is truncated (by an incomplete download, for example), its header promises more data than there is; if someone renamed another format to .brstm, it does not start with RSTM. Either way, BRSTM Player detects it and skips it before trying to play it.
DSP-ADPCM: why they are so small
Almost every BRSTM uses Nintendo's DSP-ADPCM codec, which stores each sample in about 4 bits instead of the 16 used on a CD: the audio takes roughly 3.5 times less space. A two-minute stereo theme at 32,000 Hz is about 4 MB, and thanks to the loop those 4 MB can last for hours of music.
It is lossy compression, but very faithful for game music. The format also supports uncompressed audio (8 or 16-bit PCM), which is much rarer. The most common sample rates are 32,000 Hz (the Wii's own) and 44,100 or 48,000 Hz in community-made files.
Channels, tracks and multi-stream
A BRSTM can have one or more channels. Stereo (two) is the norm, but some games store several tracks of two channels each in a single file: for example, a calm and a more intense version of the same theme that the game blends depending on what is happening. This is called multi-stream.
A basic player only lets you hear the first track. BRSTM Player shows a selector to switch each one on and off, so you can listen to the layers separately or all together.
BRSTM, BCSTM, BFSTM: the family
Nintendo kept the same idea on later consoles, with small changes to the structure:
| Format | Console |
|---|---|
| BRSTM | Wii |
| BCSTM | Nintendo 3DS |
| BFSTM | Wii U and Nintendo Switch |
| BWAV | Nintendo Switch |
They are not interchangeable as they are: you have to convert one to use it as another. BRSTM tools has the full table and the tools to do it.
Where do BRSTM files come from?
There are two main sources:
- Games: many Wii games store their music as BRSTM files inside their sound folders.
- The community: modders convert music from many sources into looping BRSTM files to replace a game's original music. That is how large BRSTM collections of all kinds of soundtracks came about.
How to open and listen to a BRSTM file
Everyday players (Windows' own, your phone's, iTunes) do not understand BRSTM. You have three options:
In your browser, with BRSTM Player
Nothing to install, on a computer or a phone, with a library, playlists, infinite mode and per-track timing. Create a free account and pick your folder or your Google Drive.
In a desktop program
foobar2000 with the vgmstream component (Windows), or vgmstream plugins for other players.
Converting it to WAV or MP3
With vgmstream you can export the theme with as many loop passes as you like and a final fade. You lose the infinite loop, but you can play it anywhere.
We explain it step by step in How to play BRSTM files.