DJ Rusty

A browser-based two-deck DJ mixer that works with local audio files.

Features

• Dual decks — Import local audio files (MP3, WAV, FLAC, OGG, M4A/AAC) via drag-drop or file picker; each deck maintains its own queue with auto-advance
• CDJ transport — Sample-accurate play/pause/cue, beat-grid, tap-downbeat, SYNC
• Jog wheel + real scratch audio — Interactive platter with a VINYL mode toggle per deck: dragging scratches the track with sample-accurate reverse/variable-speed playback (via a custom AudioWorklet), or — with VINYL off — applies a temporary pitch bend without stopping playback
• Unified performance pads — One 8-pad grid per deck, switchable between four modes: HOT CUE (8 cues), LOOP (beat-synced loop lengths), SLICER (live beat-slice triggering with adjustable window size), and SAMPLER (8 one-shot sample slots, drag-drop or click to load, independent of the channel mixer)
• Manual + beat-synced loops — IN/OUT/RELOOP for manual loop points, beat-synced loop lengths, beat-jump (±1/2/4/8 bars), SLIP mode (shadow playhead keeps time through loops/scratches)
• Full channel strip — GAIN (input trim), 3-band EQ with kill switches, high-pass/low-pass filter sweep, Echo/Reverb FX with BEAT/TIME sync, QUANTIZE and SHIFT modifiers
• Continuous pitch slider — 0.5×–2.0× playback rate, with exact SYNC between decks and a live beatmatch guide
• Crossfader + mixer — Per-deck gain/volume, EQ columns flanking the mixer's channel strip, crossfader with selectable curve, VU meters
• Per-deck waveform — Frequency-colored waveform (bass/mid/high) at the top of each deck, with hot-cue markers and a live playhead
• Library Browser — Filter imported tracks; load to Deck A/B; remove from library
• Named sessions — Save/load/delete named sessions in IndexedDB (persists audio bytes + both deck queues + per-track hot cues + beat grid + loops + sampler slots)
• Client-only — No server, no accounts, no network requests; everything runs in your browser

Quick start

npm install
npm run dev        # Vite dev server on :5173

Testing

npm run test       # Vitest (jsdom)
npm run lint       # ESLint, zero-warnings policy
npm run build      # tsc -b && vite build

Architecture

Single Web Audio backend. Every deck command goes through the DeckPlayer interface in src/services/playerRegistry.ts. The full Web Audio signal chain (EQ/filter/effects/waveform/scratch) lives in src/services/audioEngine.ts. Zustand stores in src/store/ manage deck/mixer/library/playlist/sampler/session state.

• src/components/Deck/JogWheel.tsx + src/services/scratchProcessor.ts — interactive platter and the AudioWorkletProcessor driving real sample-accurate scratch playback
• src/components/Deck/PadGrid.tsx (+ PadGridHotCue/PadGridLoop/PadGridSlicer/PadGridSampler) — the unified, mode-switched performance-pad grid
• src/store/samplerStore.ts + src/services/samplerEngine.ts — per-deck sample slots and their dedicated playback bus (bypasses the channel fader/crossfader, still scaled by MASTER)
• src/components/Mixer/EQPanel.tsx — per-deck EQ, rendered inside the Mixer as columns flanking its channel strip (not inside the deck itself)
• src/store/libraryStore.ts — session-scoped imported track list with blob URL lifecycle
• src/services/sessionStore.ts — IndexedDB save/load/list/delete for named sessions
• src/components/Library/LibraryBrowser.tsx — filterable library with Load-to-Deck
• src/components/Session/SessionPanel.tsx — session save/load/delete UI

Layout is designed and tested against a 1366×768 minimum viewport (see --min-viewport-width in src/index.css).