Free online MKV to MIDI converter

A program such as a digital audio workstation, notation editor, or MIDI keyboard requires MIDI rather than a video container. Converting an MKV recording therefore means extracting its audio and transcribing detected notes into MIDI; it is not a direct container-format change.

What the MKV format is

MKV, or Matroska Video, is a container that can hold video, multiple audio tracks, subtitles, chapters, metadata, and attachments. OBS Studio, FFmpeg-based recording tools, screen recorders, cameras, and video editors commonly create MKV files. The file may contain speech, environmental sound, or compressed music, but MKV itself does not describe musical notes.

What the MIDI format is

MIDI is event data rather than recorded sound. A MIDI file stores events such as note number, velocity, duration, instrument program, tempo, controller changes, and timing. DAWs, notation applications, hardware synthesizers, and music sequencers can edit or replay these events using their own instruments.

MIDI files are usually much smaller than audio files and allow individual notes, tempo, key, and instrumentation to be changed. They do not preserve the original singer, recording ambience, effects, or exact sound; playback depends on the synthesizer or virtual instrument.

How to actually convert MKV to MIDI

Desktop method with FFmpeg and Basic Pitch

1. Install FFmpeg and the audio-to-MIDI transcription tool Basic Pitch.
2. Extract the first audio stream from the MKV as an uncompressed WAV file:

ffmpeg -i input.mkv -map 0:a:0 -vn -ac 1 -ar 44100 -c:a pcm_s16le extracted.wav

-map 0:a:0 selects the first audio track, -vn removes video, and mono 44.1 kHz PCM provides a suitable transcription source. Choose another audio stream with -map 0:a:1 if the MKV contains separate music and speech tracks.

3. Install Basic Pitch with python -m pip install basic-pitch.
4. Generate a MIDI file:

basic-pitch midi_output extracted.wav

Basic Pitch writes a detected MIDI sequence into midi_output. Import that file into a DAW or notation program using File → Import or the equivalent MIDI command, then assign an instrument and correct notes, timing, and unwanted detections.

Free browser method

You can upload the MKV to 101convert.com and convert it for free without installing software. The service must analyze an audible music track to create note events; it cannot recover MIDI information that is not present in the recording.

Quality and compatibility limits

This conversion is an audio transcription process, so results depend on the recording. Isolated monophonic instruments usually produce better notes than full mixes. Speech, drums, reverb, distortion, background noise, polyphonic chords, changing instruments, and simultaneous vocals can create false notes or missed notes.

If the MKV contains only video, subtitles, or speech, there may be no useful musical content to convert. If it contains an original MIDI file as a Matroska attachment, extract that attachment instead of transcribing audio; inspect attachments with mkvmerge -i input.mkv and use the MKVToolNix Header editor or mkvextract to save it.

MIDI has no universal audio sound, so the result may sound different until you select an appropriate virtual instrument. Tempo and pitch may also require manual correction, and copyright restrictions can apply to the source recording and the generated arrangement.