Free online WEBM to MIDI converter

What the WEBM format is

WEBM is a Matroska-based container commonly carrying VP8, VP9, or AV1 video and Opus or Vorbis audio. Browsers, screen recorders, video editors, streaming platforms, and conferencing software frequently create or provide WEBM files. A WEBM file may contain video, audio, subtitles, or no audio track at all.

MIDI cannot contain recorded speech or waveform audio, so a WEBM file with dialogue, environmental sound, or a full mixed song cannot be preserved exactly in MIDI. The usable source is an isolated, pitched musical performance.

What the MIDI format is

MIDI is a sequence of performance instructions rather than an audio recording. Events can specify note number, start time, duration, velocity, instrument program, control changes, tempo, and pitch bend; a synthesizer or digital audio workstation renders those events through an instrument.

MIDI files are useful for editing individual notes, changing instruments, transposing music, quantizing rhythm, driving keyboards, and importing melodies into notation software. They are usually much smaller than audio, but they do not preserve the original singer, instrument tone, room sound, or effects.

How to actually convert WEBM to MIDI

Desktop workflow with FFmpeg and Basic Pitch

1. Check that the WEBM contains an audio stream with ffprobe input.webm. If it reports only video, there is no material to transcribe.
2. Extract and resample the audio to a transcription-friendly WAV file:
   ffmpeg -i input.webm -vn -ac 1 -ar 22050 -c:a pcm_s16le audio.wav
-vn removes video, -ac 1 creates mono audio, and -ar 22050 sets the sample rate.
3. Install Spotify Basic Pitch in a Python environment with python -m pip install basic-pitch.
4. Generate a MIDI file with basic-pitch output audio.wav. The program writes a MIDI result and, depending on its version, note-event and model-output files in the specified output directory.
5. Open the generated MIDI in a DAW or notation program, then correct missed notes, false detections, note lengths, tempo, and instrument assignments. Save it through File → Export or File → Save As as a Standard MIDI File.

Basic Pitch works best with a clean monophonic melody or a small number of clearly separated instruments. For piano or dense polyphonic arrangements, use a DAW or transcription application with stem separation and a piano-specific transcription model, then edit the resulting MIDI manually.

Using the online converter

You can try the built-in free converter on 101convert.com without installing software. If the service accepts the WEBM file, its result should be treated as an automatic transcription: inspect the MIDI in a piano roll or notation editor because audio-to-MIDI analysis can produce incorrect notes, timing, and instrument tracks.

Quality and compatibility limitations

WEBM-to-MIDI is transcription, not lossless conversion. Speech, drums without clear pitched fundamentals, reverb, background noise, clipped audio, simultaneous instruments, and changing tempo reduce accuracy. A mixed WEBM soundtrack generally produces a rough approximation rather than a separate, editable arrangement.

Separate the source into vocal, bass, melody, and accompaniment stems before transcription when possible. Trim silence, reduce noise, and avoid excessive compression; these changes improve note detection but cannot recover information already missing from the recording.

MIDI files may contain multiple tracks, but automatic tools often create one merged track or assign a generic piano program. Standard MIDI File Type 1 is the safer choice for retaining separate tracks; Type 0 combines events into one track. Playback depends on the destination synthesizer, so the same MIDI can sound different in a DAW, notation program, keyboard, or media player.