PitchLab MK2
A Chrome extension that turns any web audio player into a reference deck for DJs and crate diggers.
No time-stretching. No key lock. Playback behaves like a physical system, not like a DAW.
Designed for listening and verification, not performance.
What it is
PitchLab MK2 is a browser extension that intercepts web audio playback (YouTube, Bandcamp, embedded players) and routes it through a local reference engine.
It is not a DJ app, not a DAW, and not a beatgrid tool. It is a reference environment: change rate and you hear the consequences.
Playback engine
- Direct rate control via
HTMLMediaElement.playbackRate - Browser pitch-preserve flags explicitly disabled
- No phase vocoder or time-stretch layer
Live BPM analysis
Real-time BPM estimation derived from the audio signal itself (envelope extraction + autocorrelation).
- Signal-derived BPM (when accessible)
- Confidence scoring
- Half-time / double-time correction
- Stabilisation to reduce jitter
Manual BPM tools
- Manual base BPM input
- Tap BPM with hysteresis
- Context-aware reset logic
Mixer & filters
A local Web Audio graph is built on top of the page media. Nothing is uploaded. Nothing leaves the browser.
- Pre-analysis gain stage
- High-pass and low-pass filters
- Stereo-safe routing
Metering
- Dual-channel (L/R) analysis
- Peak dBFS and RMS-derived VU
- Hardware-inspired ballistics
Measurement, not decoration.
What it is not
- ❌ Time-stretching engine
- ❌ Key-lock tool
- ❌ Beat-gridding system
- ❌ DJ performance app