Free online OPUS to MID converter

What the OPUS format is

OPUS is a lossy audio codec designed for speech, music, and low-latency streaming. It commonly appears as an .opus file inside an Ogg container and is created by WebRTC applications, Discord, WhatsApp, Signal, browsers, FFmpeg, and dedicated recording software. An OPUS file contains a waveform encoded for playback; it does not contain a ready-made sequence of MIDI notes.

What the MID format is

MID, also written as .midi, is a Standard MIDI File containing events such as note number, velocity, duration, tempo, controller changes, and instrument assignments. It normally contains no recorded audio, so playback depends on a synthesizer, sound module, virtual instrument, or the receiving device.

MIDI is useful for editing individual notes, changing tempo without changing pitch, triggering software instruments, controlling keyboards, and transferring musical arrangements between compatible programs. Its files are usually much smaller than audio files, but a MIDI transcription cannot preserve speech, room sound, singing timbre, effects, or the exact sound of the source recording.

How to actually convert OPUS to MID

Use an audio-to-MIDI transcription tool rather than a normal audio format converter. A practical desktop workflow uses FFmpeg to decode OPUS and Spotify’s Basic Pitch to estimate notes.

1. Install FFmpeg and decode the source into an uncompressed WAV file:
   ffmpeg -i recording.opus -ar 44100 -ac 1 recording.wav
2. Install Basic Pitch in a Python environment:
   pip install basic-pitch
3. Run Basic Pitch on the WAV file. Its command-line syntax can vary by release; check basic_pitch --help, then provide the WAV input and an output directory. A typical installation accepts a command similar to:
   basic_pitch midi_output recording.wav
4. Open the generated .mid file in a MIDI-capable application such as MuseScore, REAPER, Cubase, Logic Pro, or Ableton Live. Correct wrong notes, remove false detections, and assign an instrument before exporting or using the result.

For a no-install attempt, upload the file to the OPUS-to-MID converter on 101convert.com and download the generated .mid file. The service must perform audio transcription, so the result should still be checked in a MIDI editor.

For monophonic material, isolate one melody or instrument before transcription. Basic Pitch and similar tools generally produce better results from a clean recording with little reverb, moderate volume, and a clearly audible melodic line. Polyphonic recordings can produce overlapping notes, incorrect octaves, and percussion or accompaniment notes that require manual cleanup.

Quality, compatibility, and limitations

This conversion is inherently approximate because OPUS is compressed audio and MID is symbolic musical data. Speech, noisy recordings, chords, drums, sustained effects, vibrato, and heavily processed sounds are difficult to represent accurately. The original OPUS audio cannot be reconstructed from the MIDI output.

FFmpeg’s WAV step does not improve quality; it only gives the transcription tool decoded PCM audio. Use a higher-quality source when available, and avoid repeatedly re-encoding the OPUS file. A MIDI file may open without audible output if the target application has no assigned instrument or MIDI device, so select a virtual instrument or software synthesizer after import.