f822e4231f
- HW = exactly 2 ratio sequences (memlcelium verbatim); browser = arbitrary N (each gate = own 7-param track), net reshapes; note 126-output WASM cap. - Gates OPTIONAL in CV mode: slider 0-14 (was wrongly floored at 3); first 3 use the free gate-only digital jacks, CV = gates<=3 ? 11 : 14-gates. - Split-net input = per-input-channel engine routing (pad->2nd pad, gamepad->double-stick, MIDI->per-CC Continuous|Rhythm tag). - Internal BPM clock; external-MIDI-clock sync + pulse-width + continuous velocity recorded as deferred niceties. - Cross-ref the existing slp_workshop mode (workshop/synth-fw-audit).
231 lines
11 KiB
Markdown
231 lines
11 KiB
Markdown
# SLP-Workshop — output modes, gate sequences & config UX
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**Status:** DRAFT / spec-only (2026-06-28). The SLP-Workshop firmware exists as
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the `slp_workshop` mode (Synth Library Portland workshop; reuses the MEMLCelium
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engine + MLP shape verbatim, foregrounds the Jolt / OU-noise learning gestures —
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branch `workshop/synth-fw-audit`). The **three output modes** below are a planned
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evolution: compile-time *slices* of that mode. This document specs the mode model,
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the Manifold-side gate-sequence configuration, and a proposed UI so the firmware
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and the browser app stay aligned. The output-mode slicing + Manifold config are
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NOT implemented yet.
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Companion docs: `docs/useq-celium/protocol.md` (the CV wire protocol), the
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manifold backends (`manifold/src/backends/`), the input layer
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(`manifold/src/inputs/`).
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**Decisions locked (2026-06-28, operator):** (1) hardware keeps exactly 2 ratio
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sequences (memlcelium verbatim); the browser may instantiate as many as the user
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wants. (2) The 3 uSEQ gate-only jacks make gates *optional* — pure CV is valid;
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if doing gates at all, use those 3 first, then convert CV jacks. (3) Split-net
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input is per-input-channel engine routing (each pad/stick/CC tagged Continuous or
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Rhythm). (4) Internal BPM clock now; external-MIDI-clock sync is a later nicety.
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---
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## 1. Ground truth: what `memlcelium` actually is
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`memlcelium` is the **hybrid**, and it is **one MLP**, not two:
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- Net: `MLP<4, [10,14,18], 56>` (`nisps/engines/memlcelium.hpp`).
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- The 56 outputs are split:
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- `[0..13]` — **sequencer**: 2 sequences × **7 ratio-seq params** each.
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- `[14..55]` — **synthesis**: 42 continuous params (Voice 0 + Voice 1).
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- The single net therefore produces **both** the continuous values **and** the
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RatioSeq parameters. An internal RatioSeq tick turns the seq params into note
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triggers; the engine already exposes `pop_events()` so those triggers can be
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consumed externally (MIDI / CV / gate) — that is the hook for gate outputs.
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So the **two-separate-networks** hybrid is a genuinely different topology (two MLP
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heads), which is why the hardware does the shared-net version and only the browser
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(more compute, dynamic) does the split one.
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### 7 ratio-seq params per track
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`ratios[0..2]` (3), `phasor_mul` (1), `phase_off` (1), `amp_ratios[0..1]` (2) = 7.
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(The April browser uSEQ-Celium used 8 — it added a pulse-width param. Use **7**
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for firmware parity; pulse width can be an optional 8th later.)
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---
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## 2. The unifying model: two output STREAMS
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Everything below collapses to two output streams, each driven by an MLP head:
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| Stream | MLP outputs | Generates | Routes to |
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|----------------|----------------------------------|----------------------|----------------------|
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| **Continuous** | 1 value per channel | smooth 0..1 values | MIDI CC / CV jack |
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| **Rhythm** | 7 params per gate-sequence track | clock-driven gates | MIDI note / gate jack|
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A **mode** is just *which streams are active* and *whether they share a network*.
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### How the Rhythm stream generates gates (RatioSeq)
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Per gate-sequence track, each control tick (`nisps/engines/*` `ratio_seq_*`):
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1. A shared **internal-BPM clock** advances a bar phasor. (External-MIDI-clock
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sync is a desirable later addition, not a launch requirement — operator.)
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2. `seq_phasor = (bar_phasor × phasor_mul + phase_off) mod 1`.
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3. `ratio_seq_3(seq_phasor, ratios, pw=0.5)` → **boolean gate** (the 3 ratios
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carve the cycle into proportional segments; the phasor's segment + pulse-width
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decide high/low).
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4. `ratio_seq_2(amp_ratios)` → **2-level velocity** (127 / 64).
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5. Rising edge → note-on / gate-high (with velocity); falling edge → note-off /
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gate-low.
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So a gate is **clock + learned pattern**, not a threshold on a continuous value —
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this is what makes "Rhythm" a distinct stream, and why it needs its own 7-params
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per track rather than one output per gate.
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**Defaults = firmware parity** (pulse width fixed at 0.5; 2-level velocity). Two
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deferred extensions, not blocking: a per-track **pulse-width** (the 8th param →
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controllable gate length, matters for envelope vs trigger) and **continuous
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velocity/accent** instead of the 127/64 two-level. Add later if the workshop
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wants them.
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> Where RatioSeq runs in the browser: when the active engine *is* the memlcelium /
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> SLP WASM engine, consume `pop_events()`. For CV/MIDI modes that don't run that
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> audio engine, a small **TS RatioSeq** fed by the Rhythm MLP's 7-params/track
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> drives the gates. (Implementation note — not built yet.)
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---
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## 3. Modes
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### Firmware (SLP-Workshop) — compile-time, one chosen at build
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Always **exactly 2 ratio sequences** (memlcelium verbatim) — the firmware does not
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vary sequence count.
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| Mode | Streams | Net | MLP output_size |
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|-----------------------|----------------------|-----|----------------------------|
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| **Continuous only** | Continuous | 1 | continuous params only |
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| **Continuous & Rhythm** (= memlcelium) | both, **shared** | 1 | 14 seq + 42 synth = 56 |
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| **Rhythm only** | Rhythm | 1 | 2 × 7 = 14 seq params |
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### Browser (Manifold) — dynamic, switchable live
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Same three **plus** a fourth, and with **as many ratio sequences as the user wants**
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(each gate sequence = its own independent 7-param track; the net reshapes to suit):
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- **Continuous & Rhythm (split nets)** — Continuous MLP + a separate Rhythm MLP.
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Browser-only (two MLP heads; hardware uses one). `output_size`: shared net =
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`continuous + 7 × n_gates` (mind the 126-output WASM cap → ~16 gates max shared);
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split net = the Rhythm net is sized independently, so it scales further.
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The browser mode is implied by the Outputs config (§4), not a separate picker:
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choosing continuous-count > 0 and gate-sequences = 0 ⇒ Continuous-only;
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gates > 0 with Shared net ⇒ hybrid-shared; gates > 0 with Separate net ⇒
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hybrid-split; continuous-count = 0 ⇒ Rhythm-only.
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---
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## 4. Configuring gate sequences (Manifold, CV **and** MIDI modes)
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The user can add **gate-sequence outputs** in both CV and MIDI modes. Two new
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controls only; everything else is automatic.
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### 4.1 The two output kinds
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- **Continuous** → CC (MIDI) / CV jack (CV).
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- **Gate sequence** → note (MIDI) / gate jack (CV). Each = one RatioSeq track.
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**MIDI mode** — two independent steppers (capped by the model output budget):
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```
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Continuous (CC): [ 8 ]
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Gate sequences: [ 2 ] each → a rhythm track → note on/off
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```
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**CV mode** — hardware is fixed (11 PWM/CV-capable + 3 digital/gate-only), so the
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two counts are *linked*. Gates are **optional** — pure CV (0 gates) is valid. One
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control:
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```
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uSEQ jacks CV 11 · Gate 0
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Gate sequences 0 ●───────────── 14
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└ first 3 are FREE (the gate-only digital jacks); the 4th+ convert a CV jack
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```
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Rule: `gates ∈ [0, 14]`; `CV = gates ≤ 3 ? 11 : 14 − gates`. So the first 3 gate
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sequences land on the dedicated gate-only jacks and cost no CV (gates 0→11 CV;
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3→11 CV; 6→8 CV; 14→0 CV). "Add more gates by swapping CV outs to gate outs" only
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kicks in past 3. (If you want gates at all, those 3 gate-only jacks are there to
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use; if you don't, they sit idle and you keep all 11 CV.)
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> Wire-protocol impact: **none**. A CV jack acting as a gate just carries 0/full
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> (or the 2-level velocity) in its `u16` slot; the 3 dedicated gate bits stay the
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> digital pins (`docs/useq-celium/protocol.md`). The CV backend's `CvSpec` already
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> lets any output target a CV *or* a gate channel — this extends it so PWM jacks
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> can be gate targets too.
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### 4.2 The Rhythm network (shown only when gate sequences > 0)
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```
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Rhythm network: ( Shared ) ( Separate ◀ default )
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```
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- **Separate** (default): the Rhythm stream gets its **own MLP**, so each input
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channel is **routed to one of the two engines** (Continuous or Rhythm). The
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routing is automatic per source kind:
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- **XY pad (internal)** → a **second on-screen XY pad** appears; pad 1 →
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Continuous, pad 2 → Rhythm.
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- **Gamepad** → **double-stick**: left stick → Continuous, right stick → Rhythm.
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- **MIDI controller** → **per-CC routing**: each learned CC has a small
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`Continuous | Rhythm` toggle, so the user assigns which knobs drive which
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engine. (The pad/gamepad cases are just the pre-grouped 2-axis versions of
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this same per-channel routing.)
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- **Shared**: one MLP drives both streams; **all** input channels feed the single
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net (one pad / one stick / all CCs). This is the hardware-parity hybrid.
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That is the whole decision surface: **two numbers + one toggle.** The second
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pad / double-stick / per-CC tag is a *consequence* of Separate, surfaced inline,
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not a separate mode control. It reuses the existing input layer
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(`InputSource.axisCount()` already supports gamepad single↔double-stick; per-axis
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labels exist via `axisLabels()`) — "Separate" adds an engine tag per input axis
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and composes a second `xy-pad` source / flips the gamepad to 4-axis as needed.
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### 4.3 Per-output detail (advanced, optional)
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In `BackendAdvanced` (full-depth modal), each output row can override the
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defaults: which model output drives each CC/CV; which rhythm track drives each
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note/gate; gate threshold (for continuous-derived gates); MIDI note#/channel; CV
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polarity. Defaults (identity assignment) make this unnecessary for the common case.
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---
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## 5. Proposed UI summary (the "simple" target)
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Outputs panel, top to bottom:
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1. **Output kinds** — `Continuous [n]` + `Gate sequences [n]` (MIDI), or the
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linked `Gate sequences 0–14` slider with the live `CV n · Gate n` readout (CV).
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2. **Rhythm network** toggle `( Shared | Separate )` + the inline input surface
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(2nd pad / double-stick / per-CC engine tags) — only when gate sequences > 0.
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3. The existing per-output rows (off/fixed/live, mute, arm, min/max/curve) +
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the per-backend specifics (CC#, CV jack, note#) as today.
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No mode dropdown for the rhythm/continuous split — the counts + toggle *are* the
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mode.
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---
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## 6. Open questions / deltas to build later
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Build deltas (when we proceed):
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- **Manifold engine**: today one MLP head on the spine. "Separate" needs a second
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Rhythm MLP head + per-input-axis engine routing. Scope: engine + input-layer.
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- **TS RatioSeq**: a browser-side RatioSeq (or a `pop_events()` bridge) to turn
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Rhythm-MLP params into gate/note events for the CV & MIDI backends. 2 sequences
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on firmware; arbitrary count in the browser.
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- **MIDI backend**: gate sequences → note on/off (it currently only sends CC).
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- **CvSpec**: allow PWM jacks (cv1..cv11) to be gate targets (incl. velocity-CV),
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with the 3 digital pins as the first-used gate jacks.
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- **Reshape**: shared-net `output_size` = continuous + 7 × gate_sequences (≤126
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WASM cap) — confirm against the reshape/reset-on-reshape flow.
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- **Firmware output_size** for "Continuous only" / "Rhythm only" — slices of the
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`slp_workshop` mode (`workshop/synth-fw-audit`); the firmware agent's call. This
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doc fixes the *shapes*, not exact counts.
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Deferred niceties (explicitly not blocking): external-MIDI-clock sync; per-track
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pulse-width (gate length); continuous velocity/accent beyond 127/64.
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