YouTube Precision Slowdown

Pitch-preserving speed control, waveform view, and beat-quantized loop selection for any YouTube video.

Slow down and loop any YouTube video without losing pitch — built for practicing an instrument, transcribing a part, learning choreography, or just studying something frame-by-frame-ish. HOW IT WORKS Open any YouTube video and click the new "Loop" button next to fullscreen/settings in YouTube's own player controls. It opens a ten-second loop at the play cursor immediately — no scan, no wait — and starts learning that passage's beats live as it plays. Click it again elsewhere in the video for a fresh loop there; click it while the panel's already open to hide it. Nothing runs automatically, and the extension does nothing at all until you click Loop. FEATURES • Speed slider, 25%-100%, with pitch preservation — independent of YouTube's own playback-speed control. • Pitch shifting: a Transpose stepper (semitones) and a Fine-tune slider (cents), for playing along in a different key or matching a recording's own tuning. • Beats learned live from whatever you loop, shown as a timeline under the player. A live band that speeds up is followed rather than averaged, so a performance that isn't at one steady tempo throughout still gets accurate beat lines wherever you loop it. • Drag on the timeline to loop a section, quantized to measures by default (hold Alt for single beats, Ctrl for unquantized). • Zoom/pan the timeline (scroll wheel or Ctrl+Up/Down), with a minimap and autoscroll during playback. • Manual correction tools for the well-known failure modes of automatic beat detection (downbeat offset, phase offset), since no algorithm gets this perfect on every track. Corrections are saved per video and reapplied automatically next time. • History: your last 10 selections in a video are remembered automatically, and any of them can be named to keep permanently. Pick one to reopen it and start playing, with the beat lines exactly as they looked when you saved it. • Full list of controls via Alt+/ anywhere on the page, or the "?" button on the panel. PRIVACY Everything runs locally in your browser. Audio analysis happens entirely on-device via the Web Audio API; nothing is ever uploaded anywhere. The only data stored is per-video beat-grid results, cached locally so a video doesn't need to be re-scanned on a later visit. No accounts, no analytics, no tracking, no data collection of any kind. Full policy: https://github.com/wsirota/youtube-precision-looper/blob/main/PRIVACY.md