MP3 to MIDI
Turn an MP3 into an editable MIDI note draft.
Yes. Local MIDI accepts MP3 files up to 20 MB and processes the audio in your browser; no account or audio upload is required.
The download is a standard .mid file containing note events—pitch, timing, and velocity—not the original sound. Open it in a DAW piano roll to move, shorten, lengthen, add, or delete notes. It is a draft for a clear single melodic line, not separated instruments or a finished arrangement.
A short MP3 workflow
Convert the file, then inspect the note events.
- Choose a clear source. Use an MP3 with one prominent melody, bass line, or other single-note part. Keep it under the 20 MB limit.
- Convert locally. Open the Local MIDI converter, select the MP3, and choose the detection sensitivity that best fits the source.
- Download and edit. Save the generated MIDI, open it beside the MP3 in your DAW, and check note pitch, starts, ends, and missing or extra events before using it in a project.
The MIDI does not preserve the MP3's instrument tone, effects, or stereo image. It is note data that can trigger a DAW instrument.
MP3-specific checks
Three source details that can change what you hear in the MIDI.
Lossy encoding can soften quiet attacks
MP3 is a lossy format. Low-level attacks, decays, or details masked by louder sounds may be less distinct after encoding; a note detector can then miss a quiet onset or merge it with a neighboring sound. This is a format caveat, not a measured Local MIDI MP3 accuracy result. If the source is important, compare the MP3 with its lossless original rather than assuming the export proves which version is more accurate.
A stereo MP3 is not split into instruments
A stereo mix still combines instruments in its left and right channels. Local MIDI's current detector reads the first decoded channel; it does not separate stems or combine the channels into independent instrument tracks. A part placed mainly in the other channel may be underrepresented. For a fair check, listen to each channel in your DAW or use a centered, isolated melody.
44.1 kHz is not a fixed conversion requirement here
The browser decodes the MP3 into audio samples, and the detector reads the decoded buffer's sample rate. Local MIDI does not force every MP3 through a separate 44.1 kHz resampling step. If you compare exports from different browsers or projects, check the decoded/source settings and the MIDI timing against the audio rather than attributing a difference to a fixed resampling rule. No separate MP3-versus-WAV benchmark has been run.
Scope: these implementation notes describe the current Local MIDI browser converter. They are not a claim that every MP3 encoder or decoder produces the same artifacts.
Related reading
Need the broader workflow or accuracy limits?
For the tool decision across audio sources, read the audio-to-MIDI workflow guide. For reproducible detector boundaries and the checks to make in a DAW, see the audio-to-MIDI accuracy guide.
FAQ
MP3 to MIDI questions
Can I convert MP3 to MIDI?
Yes. Choose an MP3 in the Local MIDI browser converter. Files up to 20 MB are processed on your device and can be downloaded as a MIDI draft.
Which audio formats can I convert to MIDI?
The Local MIDI converter currently accepts WAV, MP3, M4A, OGG, and FLAC files up to 20 MB. This page focuses on MP3 input.
How accurate is the MIDI conversion?
There is no single accuracy percentage for every recording. The current lightweight detector is intended for a clear single-note line; check missing notes, false notes, pitch, and timing in your DAW. Chords, full mixes, and strong pitch bends need more caution.
Does a stereo MP3 become separate MIDI tracks?
No. The converter does not separate instruments or create multitrack MIDI. Use an isolated melodic source and treat the download as editable note data.