Convert MP3 to MIDI, Free
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How to convert MP3 to MIDI
Converting MP3 to MIDI is a fundamentally harder problem than the reverse. MIDI contains explicit performance instructions (note on, note off, velocity). MP3 contains a compressed waveform. Extracting note-level information from an audio waveform requires pitch detection and onset detection algorithms. These work reasonably well for monophonic sources (single melody lines, solo instruments) but struggle significantly with chords, percussion, and polyphonic mixes. The conversion runs in your browser using a WebAssembly-compiled audio analysis library.
The realistic use case for MP3 to MIDI conversion is extracting a simple melody line from a recording of a solo instrument (piano, guitar, vocals) to use as a starting point in a DAW. You will almost always need to manually clean up the output: fix incorrect notes, add missing notes, adjust rhythmic quantization. Think of it as a transcription assistant rather than a perfect automated transcription. Complex polyphonic mixes (full band recordings) produce largely unusable MIDI output.
Upload your MP3
Drop a .mp3 file. Best results come from clean recordings of solo instruments with no reverb or background noise.
Select the source instrument type
Choosing monophonic (melody only) versus polyphonic mode affects which analysis algorithm is applied.
Adjust detection sensitivity
Set the note onset sensitivity and minimum note duration. Higher sensitivity captures more notes but also more noise; lower misses quiet notes.
Download the MIDI and clean up
Save the .mid file and open it in your DAW or MIDI editor. Expect to spend time correcting the output before using it.
Frequently asked questions
How accurate is MP3 to MIDI conversion?
For clean monophonic recordings (a single sung melody, a solo piano), accuracy can reach 70-85% of notes correctly detected. For polyphonic mixes, accuracy drops substantially.
Why is MP3 to MIDI harder than MIDI to MP3?
MIDI to MP3 is synthesis from structured data. MP3 to MIDI is transcription from an unstructured waveform, which is an inverse problem. The same waveform can be produced by infinitely many combinations of notes.
What happens to drums and percussion in the MIDI output?
Percussion is detected as note onsets but is not reliably assigned to correct GM drum notes. The output will typically be a rough approximation that requires significant manual correction.
Can I use this to transcribe a guitar solo?
A clean single-guitar recording will give usable results for a starting point. Bends, vibrato, and slides are hard to represent in MIDI; expect these to show as pitch artifacts in the output.
Will the tempo and time signature be detected?
Beat detection algorithms can estimate tempo, and this is used to quantize note positions in the MIDI output. For recordings with a strong rhythmic pulse, tempo detection is fairly reliable.