Format-aware byte rot for Standard MIDI Files. Headers stay valid, the music doesn't.
Drop in a .mid file, push the faders, and listen to it fall apart — then download the wreckage and open it in any DAW. Everything runs client-side in your browser; nothing is uploaded anywhere.
▶ Live demo: https://randomtypek.github.io/ROT-1/
Randomly flipping bytes in a MIDI file almost never produces glitchy music — it produces silence or a parser error. The format is fragile in three specific ways:
- Delta times are variable-length quantities. Flip the high bit of a VLQ byte and the parser desyncs from that point on.
- Running status. Files omit repeated status bytes, so corrupting one status byte misinterprets everything after it.
- Track length headers.
MTrkchunks declare their byte length up front; insertions and deletions break parsing immediately.
ROT-1 instead fully parses the file (VLQs, running status, meta and sysex events included), mutates only the musical payload, and re-serializes with correct headers, lengths, and delta times. The output is a 100% valid SMF that any sequencer will open — it just sounds wrong in exactly the way you dialed in.
| Fader | What it rots |
|---|---|
| Pitch chaos | Randomly transposes notes (up to ±3 octaves at full tilt) |
| Velocity chaos | Randomizes note dynamics |
| Time smear | Jitters note timing by up to a full beat |
| Note decay | Notes simply vanish |
| Instrument roulette | Rerolls GM program changes — injects them on tracks that never had any |
| Tempo warp | Bends existing tempo events and injects random BPM lurches at high settings |
All corruption is seeded: the same seed + fader positions always produce the same result. Hit Re-roll seed for a fresh disaster with identical settings.
Note-offs follow their note-ons through pitch changes and deletions, so corrupted files never have stuck notes.
- Decay overlay — piano roll showing original notes as amber ghosts with the corrupted state burning on top, so you can see exactly what moved, mutated, or died
- Rot log — every individual mutation reported (
note E4 → G#7,120 → 832 BPM) - A/B playback — built-in Web Audio synth to compare original vs. corrupted, including tempo-warp time stretching
- Valid output — download as
.rot.mid, verified against an independent parser (@tonejs/midi) - Demo loop included — try it without hunting for a MIDI file
- Zero dependencies, zero backend — one HTML file, works offline
Open the live demo, or clone and open locally:
git clone https://github.com/YOURUSER/midi-corruptor.git
cd midi-corruptor
xdg-open index.html # or just double-click it- Drop a
.midfile onto the deck (or click Load demo loop) - Push faders until it sounds appropriately broken
- ▶ Corrupted to preview, ⬇ Download to export
- The preview synth is oscillator-based, not a soundfont — instrument roulette sounds far more dramatic in a real DAW than in the browser preview
- SMPTE-division files are handled with approximated timing
- Sysex and most meta events pass through untouched (only tempo gets warped)
MIT — corrupt responsibly.