CHPTR

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Release notesLaunch
CHPTR — preview

CHPTR is a browser-based creative instrument that turns videos into audiovisual art. Load a video, chop it into a beat-synced sequence, and CHPTR scores it for you — every cut triggers a note, and motion, brightness, and color shape the music as it plays. Free, in your browser, nothing to install.

Features

  • Beat-synced chopping. Chop any video into a sequence that locks to the beat.
  • Self-scoring soundtrack. Every cut triggers a note, so the edit composes its own music.
  • Video-reactive. Motion, brightness, and color shape the generated notes.
  • Recompose by dragging. Drag clips to rearrange the picture and the music at once.
  • 19+ real-time GPU effects. Dithering, halftone, CRT, glitch, RGB shift, engrave — all rendered live.
  • 32 sound presets across 5 engines. Or load your own samples.
  • Flexible export. MP4 with the music baked in, or music and video on their own.

Demonstration

CHPTR promotional video

Use cases

  • Make audiovisual pieces. Turn a random video into a finished, effect-treated artwork to post or share.
  • Find a starting point. Use the generative score as a sketch to build on elsewhere.
  • Pull stems. Export the music or the treated video on their own and take them into another tool.

Details

  • Generative, not random. Note choices follow tonal gravity and voice-leading, and motifs recur and develop — phrases feel composed, not scrambled.
  • Browser-native. Nothing to install and no account — open the link and start.

Requirements

Runs entirely in your browser, nothing to install. For the best experience use a recent desktop and a Chromium-based browser (Chrome, Edge, Arc) — the real-time effects and generative audio render live, and MP4 export relies on video encoding Chromium handles natively. Safari and Firefox play fine but fall back to WebM, or may not export at all.

Release notes

v1.1.1 — July 23, 2026

  • Fix: Randomize now honors the Duration field. The length shown in the toolbar (e.g. 00:30) only took effect after manually editing it — otherwise Randomize quietly chopped to the source video's length instead. What the field shows is now always what you get.
  • Fix: A failed export can no longer break the session. If video encoding errored mid-export, graphics resources were left stranded — after a few attempts the live preview could freeze until reload. Exports now clean up fully whether they succeed, fail, or get cancelled.
  • Fix: Pressing play during an export no longer risks corrupted frames in the exported file — playback stays paused until the export finishes.
  • Fix: Double-tapping play could start playback twice, doubling up notes and timers. It now toggles cleanly no matter how fast you tap.
  • Fix: Quickly pausing and resuming briefly stacked two copies of the ambient texture layer, causing a short loudness wobble. Resuming is now seamless.
  • Fix: Muting the Generated Audio or Video Audio block in the mastering rack produced an audible click mid-playback; it now fades smoothly.
  • Fix: Setting a minimum segment length longer than a short clip produced segments past the end of the video — silent restarts in preview and frozen frames in export. Segment bounds now stay within the clip.
  • Improved: Faster rendering in preview and export — video frames now upload to the GPU without reallocating memory on every frame, most noticeable at 4K export resolutions.
  • Improved: Long sessions stay lean. Error dialogs, repeated exports, and repeated video loads now fully release their resources instead of slowly accumulating.
  • Improved: Exporting before a full loop completes now reproduces the exact same chord progression every time — the last remaining source of randomness in export is now gone.

v1.1.0 — June 11, 2026

  • New: Drone. A sustained tonic note now sits underneath the generated melody, giving it a harmonic floor — and a floating, sus-like color when the chords drift away from it. The "held" foundation under the "moving" melody.
  • Improved: More musical melodies. Note choices now follow tonal gravity and voice-leading — stepwise motion, a pull toward the stable scale tones, and leaps that resolve — instead of a looser random walk. Lines feel more intentional and singable.
  • Improved: Motifs that develop. A melodic idea now recurs and evolves by moving up a step or down a third (a musical "sequence") rather than scrambling, so phrases feel composed instead of random.

v1.0.1 — June 10, 2026

  • Fix: Removed a persistent crackle on synth-mode oscillator presets while in live mode. Presets like Ghost Light, Razor Fade, and Fog Drift had a faint click on every note that came across like vinyl crackle — it's gone.
  • Fix: Bell Wash no longer distorts. Its output was too hot and clipped on sustained chords; lowered it for clean headroom.
  • Improved: Cleaner stop. Delay and reverb tails no longer crackle in the moment after you pause playback.
  • Improved: Smoother reactive mastering. Internal level and tone changes now glide instead of stepping, removing occasional clicks when the music shifts energy.
  • Improved: Tidier voicing at peak polyphony — a cut now rests cleanly instead of abruptly cutting every ringing note.

v1.0 — May 14th, 2026

  • Initial release.