rondocode (fork)

Live-codeable synths and mini-notation patterns, in the browser. You write two kinds of code. Synths are functions that wire oscillators, filters and envelopes into a sound. Patterns are mini-notation sequences that trigger those synths in time. A custom AudioWorklet DSP engine runs it all; nothing is sampled unless you load a sample.

Credits

This repository is a fork of vijaypemmaraju/rondocode, created and maintained by Vijay Pemmaraju.

The pattern engine, DSP, editor, mini-notation, MIDI importer, agent bridge, and the design of the system are Vijay’s work. This fork builds on that foundation — thank you, Vijay.

Upstream: github.com/vijaypemmaraju/rondocode
This fork: github.com/luke-hurd/rondocode

What’s new in this fork

Everything below was added after forking. Upstream already shipped the core live-coding system (synth DSL, mini-notation, AudioWorklet engine, editor, examples, MCP bridge, offline render tools, etc.). For open ideas and status, see ENHANCEMENTS.md.

App / UX

Feature	What it does
In-app MIDI import	Project library → midi — pick a .mid, get an editable project (synths, patterns, setCps). Same converter as the CLI (midiToRondocode).
Offline WAV export	Header export → bounce the current program offline to a 16-bit WAV.
Live master recording	Header export → rec / stop — capture the master bus to a downloadable WAV.
Web MIDI in	Header MIDI control + connected controllers trigger noteOn/noteOff on a chosen live synth (fail-open if unsupported).
Web MIDI out	Pattern-scheduled notes are forwarded to MIDI outputs (not MIDI-in echoes). Optional MIDI clock API on the out handle.
Sample packs	Built-in procedural packs in the samples popover: core (vox, pad, riser) and kit (kick, snare, hat, clap), with preview + insert.
Mixer bus faders	Shared bus() send amounts + bus gain appear in the mixer and edit the code (same rewrite path as inline widgets).
Mobile header overflow	Narrow viewports collapse secondary header actions into an overflow menu.
Agent → editor sync	Successful MCP eval_code rewrites the CodeMirror buffer to match what’s playing; get_code also returns editorDoc.
Jam rooms	?room= live collab via PartyKit + Yjs + y-codemirror.next — shared buffer, presence, driver-mode Run, local audio per peer. See docs/jam.md.
Shared transport	Driver play/stop + cps with best-effort cycle-aligned start across peers.
Spectator view	?spectate=1 — read-only projection of a jam room.
Stem mute masks	Per-synth mute shared in the room control plane (local gain).
Sample CDN hooks	Room can publish {name,url} packs; peers fetch into the Worklet.
GitHub auth + cloud library	Optional Supabase Auth (GitHub OAuth) + cloud projects / room ownership (env-gated).

Pattern DSL

Feature	What it does
squeezeBind	For each event, play an inner pattern time-stretched into that event’s slot.
chop(n)	Subdivide each event into n equal pieces (rhythmic chop).
.striate(n)	Chop into n slices and set begin/end (0..1) so sample() plays successive buffer regions (Tidal/Strudel-style).
Mini a*[2 3] / a/[2 1]	Pattern-valued speed-up / slow-down factors via squeeze-bind.
Mini 0 .. 7	Inclusive integer ranges (also 0..7); max 128 steps.
Richer scales	Extra tables for .scale(...): blues, majorBlues, harmonicMinor, melodicMinor, hungarianMinor, wholeTone, diminished, augmented, enigmatic, …
density / hurry	Aliases of fast (Tidal/Strudel naming).
mask / inside / outside / zoom	Bool gating, apply-in-sped-up-time, apply-in-slowed-time, cycle-window magnify.
binary(n)	Boolean rhythm from binary digits (handy with struct / mask).
.echo / .ping	Tempo-synced musical delay (layered copies); ping-pong stereo taps.

Engine / DSP / analysis

Feature	What it does
Sample-accurate setParam	Protocol + realtime queue support atFrame so patterned params land with the note, not ~one lookahead early.
note.midi	Discrete MIDI note signal alongside note.freq (handy for wavetable position / selects).
feedback(fn, time, opts?)	Delayed feedback loop combinator (Karplus-style / external echoes).
Sample begin / end	sample() auto-wires begin/end params (0..1) for region play; override with opts. Powers .striate().
Stereo samples	Loaded stereo files keep L/R (no host downmix); imaging preserved through gain-only paths (mul/adsr).
Shared send buses	bus('space', fx, { pad: 0.4, pluck: 0.25 }, { gain: 0.8 }) — one FX chain, many synths feed; mixer faders rewrite the send literals.
truePeak	Inter-sample peak in offline analysis.
melBands + melDistance	32-band log-mel mean spectrum; cosine distance in compare_renders.
Integrated LUFS	BS.1770-style K-weight + dual gating on analyze(); lufs in render-tool readings and compare deltas.

Tooling / docs

Feature	What it does
CI vite build	GitHub Actions builds the app in addition to typecheck + tests.
Biome lint	pnpm lint + CI lint step (starter rules; intentionally permissive).
/llms.txt	Docs guide + reference as Markdown for LLMs (also a copy button in the docs UI).
scripts/render-code.ts	Headlessly bounce curated demo programs to WAV.
ENHANCEMENTS.md	Fork backlog / what’s done vs still open.
Docs / agent-guide	DSL reference + MCP agent guide updated for editor sync, new combinators, and LUFS/mel analysis.

Jam rooms (live collab)

Flok / Estuary-style multiplayer: share a URL, edit one buffer together, each browser renders audio locally. Sync the code and control plane, not PCM.

pnpm jam    # PartyKit on :1999
pnpm dev    # app on :6060
# open http://localhost:6060/?room=demo in two browsers

Piece	Behavior
Shared buffer	Yjs CRDT over PartyKit (y-codemirror.next) — everyone types in the same program.
Driver	One peer owns Run / play-stop; others edit. Claim drive in the jam bar to hand off.
Presence	Nickname + color; see who’s in and who drives.
Transport	Shared cps + play/stop with a short aligned start across peers.
Spectator	?spectate=1 — read-only projection view.
Stems / samples	Optional per-synth mute masks; room can publish {name,url} sample packs.
Saving	You’re co-writing a shared score. Header export bounces that program on your machine (same as solo). Local IndexedDB copies and optional Supabase cloud projects are per-user.
Accounts	Optional GitHub OAuth via Supabase (env-gated). Anonymous rooms work with no sign-in.

Solo / offline still works with zero network — rooms are opt-in. The MCP bridge supersede path is unchanged (agents attach to the driver’s tab, not PartyKit).

Full notes: docs/jam.md.

Monorepo layout

pnpm workspace, TypeScript throughout. Packages import each other by name (@rondocode/pattern, resolved to src/ via workspace symlinks).

Package	What it is
@rondocode/pattern	Pure pattern engine: Pattern/Hap/TimeSpan/Fraction, mini-notation parser, combinators, scales, chords, the scheduler, and the MIDI importer (src/midi.ts). No audio, no DOM.
@rondocode/engine	The DSP: oscillators, filters, envelopes, effects, the synth() builder, offline render, WAV encode.
@rondocode/app	The browser app: CodeMirror editor, the live audio session, the docs panel, the built-in examples (src/examples/index.ts).
@rondocode/server	Headless/bridge tooling and dev scripts.

Develop

pnpm install
pnpm dev        # vite dev server on http://localhost:6060
pnpm jam        # PartyKit jam rooms on :1999 (optional)
pnpm test       # the whole vitest suite
pnpm test:watch # watch mode
pnpm lint       # Biome (this fork)

Optional env vars: see .env.example (VITE_PARTYKIT_HOST, Supabase keys for cloud auth).

Type-check with pnpm --filter @rondocode/app exec tsc --noEmit (or per package). Do not run tsc -b in this repo: it emits .js into src/ and vite then loads the stale .js over the .ts. Always use tsc --noEmit.

The DSL

Everything you can write in an example is documented in-app (the docs panel) and in packages/app/src/docs/:

• dsl-docs.ts, the reference: every scope global, Pattern method, synth-ctx member, Sig method and mini-notation operator. It is coverage-pinned: test/docs.test.ts checks it bidirectionally against the live objects.
• content.ts, the hand-written guide: short sections that each end in a complete, playable program.

Rendering examples headless

pnpm tsx packages/server/scripts/render-example.ts "veldt (full)" 52 out.wav

Agents can also use MCP render_code / render_synth / compare_renders (analysis includes lufs, truePeak, melBands, etc.).

Importing MIDI

In the app: project library → midi. From the CLI:

pnpm tsx packages/server/scripts/midi-to-rondocode.ts song.mid "my song" out.txt

midiToRondocode in packages/app/src/midi/import.ts is the in-app converter. The low-level importer lives in packages/pattern/src/midi.ts.

Inspiration

rondocode’s pattern model follows in the lineage of TidalCycles and Strudel. The pattern engine, DSP, and editor are written from scratch (Vijay’s upstream), with no Tidal or @strudel/* dependency.

Contributing

Contributions are welcome. See CONTRIBUTING.md and CODE_OF_CONDUCT.md. Example tunes must be original compositions (no transcriptions of copyrighted songs).

For fork-specific ideas and status, see ENHANCEMENTS.md.

License

MIT © Vijay Pemmaraju.

This fork remains under the same MIT license; copyright for the original work belongs to Vijay Pemmaraju.