MIDI Viewer Online — Free SMF Piano Roll & Synthesizer Player | Online Gallery
Visualize MIDI tracks on interactive piano roll and listen with built-in synth. Parse SMF Standard MIDI files into an interactive piano roll visualizer with tempo BPM, track events, and built-in synthesizer.
What is MIDI Event Viewer and what does it do?
The MIDI Music & Piano Roll Event Viewer visualizes musical pitch across octaves and plays tunes via Web Audio synth.
- Plot MIDI note events on interactive piano roll.
- Audition music using built-in oscillator synthesizer.
- Display tempo BPM and track instruments.
How does MIDI Event Viewer work?
Parses SMF chunk bytes, delta-times, Note-On/Note-Off events, and generates audio frequencies using Web Audio.
100% private: all processing happens locally in your browser using client-side WebAssembly, WebCrypto, WebAudio, and HTML5 Canvas. Your files are never uploaded to any server.
Who needs MIDI Event Viewer?
Composers & Music Producers
Preview MIDI arrangements and track structures without launching a full DAW.
Supported file formats
MIDI Music & Piano Roll Event Viewer (.mid) opens and processes the following file extensions directly in your browser:
.mid.midi.smfHow to use MIDI Event Viewer — step by step
- 1
Upload MIDI
Select your .mid or .midi song or instrumental track.
- 2
Explore Piano Roll
View pitch notes mapped across musical octaves C2 through C6.
- 3
Play Synth
Click Play Synth to audition the melody via Web Audio oscillators.
Frequently asked questions
Does it need a soundfont?
It includes a lightweight multi-voice oscillator synthesizer that plays right out of the box.
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