Convert Nintendo 3DS BCSTM music to MP3 online, with loops played through and faded out. Upload files up to 20GB and download the converted result in a few clicks.
Drag & Drop your BCSTM file here
BCSTM files, up to 20GB
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20GB upload limit.
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HOW IT WORKS
Three steps, no account, nothing to install.
01
Upload your BCSTM file
Drag and drop a .bcstm music stream extracted from a 3DS game or theme, or select it from your device.
02
Convert to MP3
Keep MP3 as the output format and start. The DSP-ADPCM or PCM audio is decoded and encoded with LAME at VBR quality 2.
03
Download the MP3
Download one MP3 per BCSTM file. It plays in browsers, on phones, in VLC and in any audio editor.
BCSTM
BCSTM is the NintendoWare music stream format of Nintendo 3DS games, such as The Legend of Zelda: Majora's Mask 3D. It holds DSP-ADPCM or PCM audio, often with a loop point so the music can repeat during play. 3DS home menu themes also store their background music as a BCSTM.
MP3
MP3 is a lossy compressed audio format built for small files and broad playback compatibility. It works on almost every phone, browser, car stereo, media player, and editing application.
FILE FORMATS
SOURCE
BCSTM is the music stream format of Nintendo 3DS games and themes. Most use Nintendo's DSP-ADPCM codec at about a quarter of PCM size, some use PCM16, and many hold several stereo tracks the game mixes live. Loop points make the music repeat without a gap, often at the 3DS-native rate of 32728 Hz.
TARGET
MPEG-1 Audio Layer III has been the universal music format since the 1990s. It compresses audio by removing sounds the ear is unlikely to hear, so a song takes a few megabytes instead of tens. ID3 tags carry the title, artist and album art, and every phone, browser, car stereo and editor plays it.
| Feature | BCSTM | MP3 |
|---|---|---|
| Developed by | Nintendo | MPEG (Fraunhofer) |
| File extension | .bcstm | .mp3 |
| Compression | DSP-ADPCM or PCM | Lossy |
| Size vs uncompressed WAV | About 1/4 (ADPCM) | About 1/7 to 1/10 |
| Tags and cover art | Loop points, no tags | ID3 tags and cover art |
| Best for | 3DS game music and themes | Music and podcasts everywhere |
| Plays on phones and browsers | No, needs vgmstream | Yes |
USE CASES
Practical workflows where BCSTM to MP3 conversion is useful.
Listen to 3DS soundtracks on your phone
Put BCSTM tracks from a 3DS game on your phone or music player as MP3s, without a 3DS or an emulator.
Hear looping music the way the game plays it
Tracks with an inner loop get the intro, the loop twice and a 10 second fade, so the MP3 does not stop abruptly at the loop point.
Preview the music of a 3DS theme
3DS home menu themes keep their background music in a BCSTM file. Convert it to hear the music before you install or share the theme.
Check extracted music for a mod
Modders can listen to original or replacement BCSTM tracks as MP3s before testing a music mod on a console or in an emulator.
Hear every layer of a multi-track song
Some 3DS songs store 2 or 3 stereo tracks in one stream. The MP3 mixes them at equal level, so every layer can be heard.
Share a track on Discord
Post a 3DS music track as an MP3, which plays right in the Discord chat.
Use game music in a video
Drop the MP3 into Premiere Pro, DaVinci Resolve or CapCut for a let's play, review or retrospective.
Find a track in a sound dump
A ripped sound folder often holds many numbered BCSTM files. Convert them in one job and skim the MP3s in any player to find the one you want.
Make a ringtone from a 3DS jingle
Turn a short 3DS jingle or fanfare into an MP3, then set it as a ringtone or notification sound on your phone.
Keep small copies of game music
A stereo 32 kHz track comes out at about 146 kbps, far smaller than WAV, which suits phones and cloud storage.
SUPPORTED FILES
BCSTM streams from Nintendo 3DS games and themes are supported.
The usual encoding in 3DS games.
Uncompressed streams decode without loss before encoding.
2 or 3 stereo tracks are mixed into one stereo MP3.
The 3DS-native rate is resampled to 44.1 kHz, which MP3 supports.
A common audio file renamed to .bcstm converts too.
Only convert audio from games you own or have permission to use.
TROUBLESHOOTING
Game audio works differently from normal music files, which explains most surprises.
01
Looping game music is rendered the way the game plays it: the looped section plays once more, then fades out over 10 seconds. A loop covering the whole track plays once.
02
Multi-track streams hold layers the game turns on and off. The MP3 mixes every layer at equal level.
03
The file holds less than 97% of its audio. Extract or download it again.
04
The file is damaged, isn't really BCSTM audio, or was extracted with the wrong tool. Extract it again from the game files and retry.
05
MP3 can't store 32728 Hz, so those tracks become 44.1 kHz.
06
Those games use BFSTM. Use our BFSTM to MP3 converter.
vgmstream is the reference decoder for game audio, used through foobar2000 or the command line. dragdropdo runs the same decoder in the browser, so you can turn BCSTM into MP3 on any device.
| What matters | dragdropdo | vgmstream and Desktop Tools |
|---|---|---|
| Nothing to install | ✓Yes. Runs in any modern browser. | ~foobar2000 plus the vgmstream plugin, or vgmstream-cli. |
| Works on phones and tablets | ✓Yes. Desktop, Android, iPhone and iPad. | ~No. Windows and command-line tools. |
| Batch conversion | ✓Yes. Add many files and download one ZIP. | ~Yes, with scripts or foobar2000's converter. |
| Share finished files | ✓Yes. Send a unique link from the result page. | ~You upload and share the files yourself. |
| Pricing | ✓Free with daily limits. $2.99 or $6.99 passes for unlimited use, no monthly plan. | ~Free. |
| Choosing loop count and fade | ✓Fixed: an inner loop plays twice, then fades over 10 seconds. | ~Yes. vgmstream-cli sets the loop count and fade length. |
Other tools use different pricing, limits and workflows. This comparison describes dragdropdo's own features without assuming every other tool works the same way.
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WHY DRAGDROPDO
Convert BCSTM to MP3 in your browser, with nothing to install and nothing kept after 24 hours.
Private by default
Files are encrypted in transit and deleted from our servers automatically after 24 hours.
No install required
Convert in any modern browser on Windows, Mac, Linux, Android, iPhone or iPad. No app and no sign-up wall.
Big files and batches
Upload files up to 20GB each, add several at once, and download the results one by one or as a ZIP.
Share & download
Save finished files to your device or pass them on with a share link from the result page.
MORE BCSTM TOOLS
BCSTM is the NintendoWare streamed audio format (CSTM) used for background music in Nintendo 3DS games and for the music of 3DS HOME Menu themes. It usually holds 4-bit DSP-ADPCM audio, sometimes PCM, and can store a loop point.
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FAQ
Answers to common questions about dragdropdo's BCSTM to MP3 converter.
