Load a track to begin
Everything runs on this device: decode, analysis, rendering and recording. Nothing is uploaded.
Source
An audio file, decoded and analyzed on this device.
Clip and export
Pick the in-point, pick a length, record. Export replays the analysis frame-exact at 30 fps.
Recording produces WebM (VP9 or VP8 with Opus audio). Vertical 1080x1920 exports run 2-4x above YouTube's recommended upload bitrate (8 Mbps for 1080p SDR); smaller formats scale with pixel count. Encoding above the recommendation means YouTube's transcode starts from quality-abundant source. Renaming the file to .mp4 does not convert it. For a true MP4 (H.264 High + AAC 320k, 48 kHz stereo) use the bundled convert server below. The exported video carries the track audio.
Runs ffmpeg inside this tab: same quality settings as the local server (H.264 High CRF 16 + AAC 320k), but software-encoded, so budget a few minutes for a 15 s clip on a phone. First use downloads about 32 MB once. Or skip conversion entirely: the WebM uploads to YouTube directly (no extra lossy encode on your device).
Fastest native option: start pulsecut-convert-server.mjs (Node + ffmpeg) on a computer or Termux and open this app through it. The browser button above needs no server at all.
Look
Scenes have their own grammar. Color follows the audio when Auto is on.
Analysis
PulseDSP: tempo, onsets, drums, groove, loudness and hook search.
Green: hook window. Amber tick: drop. Cyan line: section boundary. White ticks: beats. Tall white ticks: downbeats.
Flash safety
Photosensitivity guard, always on.
The flash guard is energy-based: it counts rising transitions of the render intensity signal that drives the visuals, and caps them at 3 general flashes per second, aligned with WCAG 2.3.1 (Three Flashes or Below Threshold). Saturated-red transitions are counted separately and throttled the same way, and a measured-luminance QA harness verifies the rendered output stays within the cap. Reduced-flash mode additionally caps brightness, slows pulses and disables bloom. If your system requests reduced motion, this mode switches on automatically. This tool is for creative visual use. It makes no health claims of any kind.