MP3 to MIDI Converter | Tonera

What

Tonera MP3 to MIDI Converter is a browser-based tool that turns MP3 audio into editable note data and exports it as MIDI, MusicXML, PDF, ABC, or a chord chart. It targets musicians, producers, transcribers, and others who need to derive notes from compressed audio, where MP3 encoding can blur quiet attacks, decays, and high-frequency harmonics. The product positions standard conversion as private and in-browser, with optional server-side high-precision stem separation for harder mixes.

Features

• In-browser standard conversion: Tonera decodes MP3 locally, converts it to 22,050 Hz mono for Basic Pitch, and does not upload audio during standard conversion.
• Note preview and cleanup: the tool shows kept and discarded notes before export and provides five sliders and controls for onset, frame, duration, frame threshold, and minimum note length to reduce compression artifacts.
• Multi-format export: one detection pass can produce MIDI for DAWs, MusicXML for notation software, PDF, ABC notation, and a chord chart.
• Optional high-precision mode: for 2 credits, it uses HTDemucs to separate the full mix before transcription; only when this mode is enabled is audio uploaded to Replicate.
• MP3-focused limits: files can be up to 10 minutes, or 3 minutes on mobile, because standard conversion holds decoded audio and model tensors in browser memory.

Helpful Tips

• Source quality matters more than bitrate alone: a direct DAW export or the highest-bitrate, least-compressed MP3 available is preferable; a clean 128 kbps solo can outperform a noisy 320 kbps full mix.
• Converting MP3 to WAV before processing does not restore information removed by MP3 compression; the original MP3 or a true WAV master is the appropriate source.
• Tiny notes are clues rather than automatic errors; compression noise, reverb, and overlapping harmonics can create short candidates, so frame threshold or minimum note length can be adjusted until kept notes follow the musical phrase.
• Solo piano, guitar, voice, and single-note leads are the strongest sources; dense drums, pads, layered vocals, and mixed masters typically require more cleanup or stem separation, and long files may need splitting around musical sections.