Merge branch 'fix/gitattributes-stray-cr'

The previous commit wrote a literal carriage-return byte into a comment, where
the text was meant to show the two characters backslash-r. Git's content sniffing
treats a lone CR as a sign of binary data, so .gitattributes itself was classed
-text (git ls-files --eol reported i/-text): the one file in the repository
that the new LF policy could not normalise.

The rules themselves were never affected - the byte sat inside a comment, and
deploy.bat and the sources were already checking out with the intended endings.

The comment now says "a trailing CR byte" in words. .gitattributes reports
i/lf w/lf, and `git add --renormalize .` stages nothing else.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01LU1NRL7fAaZTtFMTTPn2b1

.gitattributes

@@ -0,0 +1,20 @@
+# Line endings: LF in the repository and in every working tree, on every OS.
+#
+# This file is the policy, not each machine's git config. Git for Windows installs
+# with core.autocrlf=true, which checks text out as CRLF; an attribute here beats
+# that setting, so a fresh clone gets LF regardless of how its machine is set up.
+#
+# It matters beyond tidiness. tools/branding-sites.tsv is read line by line with
+# `read`, and under CRLF every row's last field gained a trailing CR byte - so the
+# branding checker reported all 29 sites as missing on Windows while passing on the
+# Linux CI runner. text=auto leaves genuinely binary files alone.
+* text=auto eol=lf
+
+# Shell scripts are pinned explicitly as well: a strict POSIX sh (dash, CI
+# containers) rejects a CRLF shebang outright rather than misbehaving quietly.
+*.sh text eol=lf
+
+# The exception. cmd.exe misparses LF-only batch files around labels and long
+# lines, so these alone are checked out CRLF. The repository copy is still LF.
+*.bat text eol=crlf
+*.cmd text eol=crlf

.github/workflows/ci.yaml

@@ -0,0 +1,71 @@
+name: CI
+
+on:
+  push:
+    branches: [ master ]
+    paths:
+      - 'src/**'
+      - 'xtask/**'
+      - 'Cargo.toml'
+      - 'Cargo.lock'
+      - 'bundler.toml'
+      - 'tools/**'
+      # This workflow validates itself: a broken step, a moved script path or a
+      # wrong runner label then fails loudly on the commit that caused it, rather
+      # than surfacing later against an unrelated source change. Note the limit -
+      # it checks the job body, not the trigger block above. Break `on:` and the
+      # symptom is silence, which looks like success.
+      - '.github/workflows/**'
+  # Mirrors the push filter. Without it a PR touching only the README would run a
+  # full build - the branch filter alone constrains where, not what.
+  pull_request:
+    branches: [ master ]
+    paths:
+      - 'src/**'
+      - 'xtask/**'
+      - 'Cargo.toml'
+      - 'Cargo.lock'
+      - 'bundler.toml'
+      - 'tools/**'
+      - '.github/workflows/**'
+  workflow_dispatch:
+
+# Target the self-hosted Rust/audio runner registered to the `musiikki` org.
+#
+# The runner is host-mode, so the rustup toolchain installed for the
+# `gitea-runner` user is used directly — nothing installs per run, and the cargo
+# registry cache stays warm between jobs.
+#
+# Adapted from musiikki/nih-plug-template. The template gates VST3 behind an
+# opt-in `vst3` feature and so builds twice; this plugin always ships VST3
+# (nih_plug is taken with default features), so one build covers both formats.
+
+jobs:
+  build:
+    name: Build
+    runs-on: rust-audio
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Toolchain
+        run: |
+          cargo --version
+          rustc --version
+          echo "CARGO_HOME=${CARGO_HOME:?not set on this runner}"
+
+      # Cheap and needs no toolchain, so it runs first: a rename that only
+      # landed in half the files is worth catching before spending a build on it.
+      - name: Branding consistency
+        run: sh tools/check-branding.sh
+
+      - name: Build
+        run: cargo build --release
+
+      - name: Test
+        run: cargo test --release
+
+      # Proves the xtask bundler still works, which a plain `cargo build` does
+      # not exercise — the bundle step is where bundler.toml and the crate name
+      # have to agree.
+      - name: Bundle
+        run: cargo xtask bundle bari_206 --release

Cargo.lock

@@ -147,6 +147,14 @@ dependencies = [
  "windows-link",
 ]
 
+[[package]]
+name = "bari_206"
+version = "0.1.0"
+dependencies = [
+ "nih_plug",
+ "nih_plug_egui",
+]
+
 [[package]]
 name = "baseview"
 version = "0.1.0"
@@ -337,14 +345,6 @@ dependencies = [
  "objc",
 ]
 
-[[package]]
-name = "codename_206"
-version = "0.1.0"
-dependencies = [
- "nih_plug",
- "nih_plug_egui",
-]
-
 [[package]]
 name = "combine"
 version = "4.6.7"

Cargo.toml

@@ -1,8 +1,8 @@
 [package]
-name = "codename_206"
+name = "bari_206"
 version = "0.1.0"
 edition = "2021"
-authors = ["Mikkeli Matlock <matlockib@gmail.com>"]
+authors = ["Mikkeli Matlock <mikkeli@novoyuuparosk.org>"]
 homepage = "https://github.com/mikkeli/codename-206"
 description = "A VST3/CLAP multiband compressor/limiter with a custom gain-curve display"
 # VST3 is on by default in nih_plug, and its bindings (vst3-sys) are GPLv3. Any
@@ -17,6 +17,14 @@ members = ["xtask"]
 # `cdylib` is the plugin binary; `lib` (rlib) lets `cargo test` link the unit tests.
 crate-type = ["cdylib", "lib"]
 
+# Future-incompatibility warnings are deferred hard errors: rustc is telling you
+# this code stops compiling on some later release. Denying the group turns that
+# into a build failure the day it appears, rather than 16 of them accumulating
+# unnoticed until a toolchain bump breaks the build on a day you did not choose.
+# Style and clippy lints are deliberately untouched - they stay warnings.
+[lints.rust]
+future_incompatible = { level = "deny", priority = -1 }
+
 [dependencies]
 # Pinned to the exact commit of the local ./nih-plug reference clone so the build
 # is reproducible and matches the examples we read from. Bump the `rev` together

LICENSE

@@ -632,7 +632,7 @@ state the exclusion of warranty; and each file should have at least
 the "copyright" line and a pointer to where the full notice is found.
 
     <one line to give the program's name and a brief idea of what it does.>
-    Copyright (C) <year>  <name of author>
+    Copyright (C) 2026  Mikkeli Matlock
 
     This program is free software: you can redistribute it and/or modify
     it under the terms of the GNU General Public License as published by
@@ -652,7 +652,7 @@ Also add information on how to contact you by electronic and paper mail.
   If the program does terminal interaction, make it output a short
 notice like this when it starts in an interactive mode:
 
-    <program>  Copyright (C) <year>  <name of author>
+    <program>  Copyright (C) 2026  Mikkeli Matlock
     This program comes with ABSOLUTELY NO WARRANTY; for details type `show w'.
     This is free software, and you are welcome to redistribute it
     under certain conditions; type `show c' for details.

NOTICE

@@ -0,0 +1,37 @@
+Bari 206
+Copyright 2026 Mikkeli Matlock
+
+Licensed under the GNU General Public License v3.0 or later.
+See LICENSE for the full terms.
+
+--------------------------------------------------------------------------------
+Third-party material
+--------------------------------------------------------------------------------
+
+The plugin scaffolding derives from the NIH-plug cookiecutter template and
+NIH-plug's example plugins, by Robbert van der Helm:
+
+    https://github.com/robbert-vdh/nih-plug-template
+    https://github.com/robbert-vdh/nih-plug
+
+Those portions are licensed under the ISC License:
+
+    ISC License
+
+    Copyright (c) 2022 Robbert van der Helm
+
+    Permission to use, copy, modify, and/or distribute this software for any
+    purpose with or without fee is hereby granted, provided that the above
+    copyright notice and this permission notice appear in all copies.
+
+    THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+    WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+    MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
+    SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+    WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
+    OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
+    CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+
+ISC is GPL-compatible, so this notice is retained rather than superseded.
+
+"VST" is a trademark of Steinberg Media Technologies GmbH.

README.md

@@ -1,4 +1,4 @@
-# Codename 206
+# Bari 206
 
 *Called 206 because the Peugeot 206 has a 'maxi' variant. You'll know this is a Maximizer knockoff if you can follow that trail of thoughts.*  
 Multiband Compressor / Limiter VST3 — Project Plan  
@@ -163,8 +163,8 @@ The project is already scaffolded (NIH-plug + nih_plug_egui, pinned to a fixed g
 
 ```powershell
 # Build + bundle the VST3 and CLAP
-cargo xtask bundle codename_206 --release
-# Output: target\bundled\Codename 206.vst3  and  Codename 206.clap
+cargo xtask bundle bari_206 --release
+# Output: target\bundled\Bari 206.vst3  and  Bari 206.clap
 ```
 
 ### Deployment
@@ -184,7 +184,7 @@ Use the provided script (no need to remember the details):
 `deploy.bat` is a double-click wrapper around the same script.
 
 After deploying, in FL Studio: **Options → Manage plugins → tick "Rescan previously failed
-plugins" → Find installed plugins**, then search for **Codename 206**. (The rescan-failed step
+plugins" → Find installed plugins**, then search for **Bari 206**. (The rescan-failed step
 is essential — without it FL silently skips a plugin it has seen before.)
 
 > **Known issue (deferred):** the **CLAP** build shows its name/vendor/type correctly in FL, but
@@ -277,9 +277,34 @@ the editor being open:
 Never pass DSP state to the UI directly.
  
 ### VST3 licensing
-You must accept Steinberg's VST3 SDK licence before distributing VST3 binaries.
-NIH-plug's VST3 bindings are GPLv3; if you distribute, the plugin must also be GPLv3
-(or you need a commercial Steinberg licence). CLAP has no such restriction.
+This plugin is **GPL-3.0-or-later** (see `LICENSE`, and `NOTICE` for attribution).
+
+`nih_export_vst3!()` links `vst3-sys`, which is GPLv3-or-later by its own authors' choice —
+they describe their port as a derivative of Steinberg's SDK that "was not made in isolation".
+That is what makes a distributed VST3 build GPL-licensed, and it holds regardless of any
+question about Steinberg's own rights.
+
+No Steinberg SDK source is vendored or redistributed here, so there is nothing to accept at
+build time. Separately from copyright, **"VST" is a trademark of Steinberg Media Technologies
+GmbH**; describing a distributed product as a VST plugin is governed by their trademark terms,
+which no source licence resolves. CLAP carries neither encumbrance.
+ 
+---
+ 
+## CI
+
+`.github/workflows/ci.yaml` gates pushes and PRs on the branding check, a release build,
+`cargo test`, and a bundle — enough to catch a rename that only half-landed, a build break,
+or a `bundler.toml` that no longer matches the crate name.
+
+It targets `runs-on: rust-audio`, a self-hosted host-mode runner registered to the `musiikki`
+org. That label is org-scoped: a fork outside `musiikki` will not see the runner and its jobs
+will queue indefinitely rather than fail.
+
+Plugin performance is deliberately not gated. Realtime cost is only meaningful against an
+audio deadline, and `Plugin::process()` cannot be called from a test at all — `ProcessContext`
+requires a `&Transport`, whose constructor and fields are `pub(crate)` to nih_plug. The DSP
+types under `src/dsp/` take no nih-plug context and are directly testable if you need it.
 
 ---
 

bundler.toml

@@ -3,5 +3,5 @@
 # [package_name]
 # name = "Human Readable Plugin Name"  # defaults to <package_name>
 
-[codename_206]
-name = "Codename 206"
+[bari_206]
+name = "Bari 206"

deploy.ps1

@@ -1,6 +1,6 @@
 <#
 .SYNOPSIS
-    Build Codename 206 and install the VST3 (and CLAP) into the system plugin folders.
+    Build Bari 206 and install the VST3 (and CLAP) into the system plugin folders.
 
 .DESCRIPTION
     FL Studio scans `C:\Program Files\Common Files\VST3` by default and ignores
@@ -25,7 +25,7 @@
 param(
     [switch]$SkipBuild,
     [switch]$User,
-    [string]$Package = "codename_206"
+    [string]$Package = "bari_206"
 )
 
 $ErrorActionPreference = "Stop"
@@ -42,8 +42,8 @@ if (-not $SkipBuild) {
     if ($LASTEXITCODE -ne 0) { throw "cargo xtask bundle failed (exit $LASTEXITCODE)" }
 }
 
-$vst3Name = "Codename 206.vst3"
-$clapName = "Codename 206.clap"
+$vst3Name = "Bari 206.vst3"
+$clapName = "Bari 206.clap"
 $bundled  = Join-Path $root "target\bundled"
 $vst3Src  = Join-Path $bundled $vst3Name
 $clapSrc  = Join-Path $bundled $clapName

src/dsp/biquad.rs

@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-3.0-or-later
 //! Generic second-order IIR biquad, Transposed Direct Form II.
 //!
 //! Coefficient formulas are the RBJ Audio EQ Cookbook

src/dsp/compressor.rs

@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-3.0-or-later
 //! Single full-band feed-forward compressor with look-ahead.
 //!
 //! Design follows Giannoulis, Massberg & Reiss, "Digital Dynamic Range Compressor
@@ -23,21 +24,36 @@ pub const MAX_LOOKAHEAD_MS: f32 = 5.0;
 /// Most channels we ever process in one frame (our audio layouts are mono/stereo).
 const MAX_CHANNELS: usize = 2;
 
-/// ~ -240 dBFS; keeps `log10` away from zero without affecting audible levels.
+/// ~ -240 dBFS; keeps the level conversion away from zero without affecting audible levels.
 const LEVEL_EPS: f32 = 1e-12;
 
+/// `ln(x) * LOG10_GAIN_TO_DB == log10(x) * 20`, but a bare `ln()` runs faster than `log10()` on
+/// most architectures (mirrors nih-plug's `util::gain_to_db_fast`). Used in the per-sample level
+/// detector, called 4x/sample (once per band + 'All').
+const LOG10_GAIN_TO_DB: f32 = std::f32::consts::LOG10_E * 20.0;
+
+/// `exp(x * DB_TO_GAIN_EXP) == 10.0f32.powf(x / 20.0)`, but `exp()` runs faster than a general
+/// `powf()` on most architectures (mirrors nih-plug's `util::db_to_gain_fast`) — `powf` has to
+/// handle an arbitrary runtime base, while this bakes `ln(10)` in as a constant. Used for the
+/// per-sample wet gain, called 4x/sample.
+const DB_TO_GAIN_EXP: f32 = std::f32::consts::LN_10 / 20.0;
+
 /// Silence-floor anchor for the below-threshold shaping: at/below this level the gain change is 0
 /// (silence stays silence), and the low region fans up/down from here toward the threshold. Matches
 /// the editor gain-curve's display floor.
 const LOW_ANCHOR_DB: f32 = -60.0;
 
-/// Exponential curvature (1/dB) for the low shaper at `low_curve` = 1. Bends the low gain toward a
-/// bounded saturation so the serial composition doesn't blow up. 0 = straight line.
-const LOW_CURVE_K_MAX: f32 = 0.1;
+/// Max bulge (dB) the low-shaper curvature adds at the MIDDLE of the low region, at `|low_curve|`=1.
+/// Bipolar: positive bulges up (boost the quiet middle), negative bulges down (suppress). Zero at
+/// both ends (silence floor and the knee), so it never moves those anchors.
+const LOW_BULGE_MAX_DB: f32 = 12.0;
 
 /// Hardcoded RMS averaging window (one-pole time constant). Deliberately small; can be
 /// promoted to a parameter later.
-const RMS_WINDOW_MS: f32 = 5.0;
+/// Default RMS averaging time constant for tests that do not care which band they model.
+/// Real instances pass a per-band value - see the `RMS_WINDOW_MS` table in `lib.rs`.
+#[cfg(test)]
+const RMS_WINDOW_DEFAULT_MS: f32 = 20.0;
 
 // Denormals (the exponentially-decaying envelope/RMS tails and the IIR filter state) are handled
 // by the CPU's Flush-To-Zero mode, which NIH-plug enables around `process()`/`reset()` via its
@@ -112,12 +128,23 @@ impl Compressor {
 
     /// Allocate delay buffers for the worst-case look-ahead. Call from `initialize()`,
     /// where allocation is allowed — never from `process()`.
-    pub fn prepare(&mut self, sample_rate: f32, num_channels: usize, max_lookahead_ms: f32) {
+    /// `rms_window_ms` is the time constant of the RMS detector's one-pole average. It is a
+    /// design constant per band rather than a user param: the squared signal carries a component
+    /// at twice the fundamental, so a window that does not span a cycle leaves the detector
+    /// rippling at 2f and the gain intermodulating with the bass. The needed window is therefore
+    /// set by how low the band goes, which the band - not the compressor - knows.
+    pub fn prepare(
+        &mut self,
+        sample_rate: f32,
+        num_channels: usize,
+        max_lookahead_ms: f32,
+        rms_window_ms: f32,
+    ) {
         self.sample_rate = sample_rate;
         self.fixed_delay = (max_lookahead_ms * 0.001 * sample_rate).ceil() as usize;
         // +1 so the oldest (output) sample and the newest (write) sample never alias.
         self.capacity = self.fixed_delay + 1;
-        self.rms_coef = Self::time_to_coef(RMS_WINDOW_MS, sample_rate);
+        self.rms_coef = Self::time_to_coef(rms_window_ms, sample_rate);
         let channels = num_channels.clamp(1, MAX_CHANNELS);
         self.delay = vec![vec![0.0; self.capacity]; channels];
         self.reset();
@@ -161,21 +188,23 @@ impl Compressor {
         }
     }
 
-    /// Low-level shaper gain in dB, anchored at the silence floor ([`LOW_ANCHOR_DB`]): 0 at/below
-    /// the floor, rising with slope `low_slope - 1` and bending toward a bounded saturation set by
-    /// `low_curve` (0..1; 0 = straight line). This reshapes the level the compressor then sees.
-    fn low_gain_db(level_db: f32, low_slope: f32, low_curve: f32) -> f32 {
+    /// Low-level shaper gain in dB. Anchored at BOTH the silence floor ([`LOW_ANCHOR_DB`]) and the
+    /// knee (threshold). `low_slope` tilts the straight line between those anchors (1 = unity);
+    /// `low_curve` (-1..1) bulges that line in the middle without moving either endpoint — positive
+    /// bulges up (boost the quiet middle), negative down (suppress). Reshapes the level the
+    /// compressor then sees.
+    fn low_gain_db(level_db: f32, threshold_db: f32, low_slope: f32, low_curve: f32) -> f32 {
         let d = level_db - LOW_ANCHOR_DB;
         if d <= 0.0 {
             return 0.0;
         }
-        let m = low_slope - 1.0;
-        let k = low_curve * LOW_CURVE_K_MAX;
-        if k <= 1e-6 {
-            m * d // straight line (curvature off)
-        } else {
-            (m / k) * (1.0 - (-k * d).exp()) // saturates to m/k (bounded)
-        }
+        let span = (threshold_db - LOW_ANCHOR_DB).max(1.0); // floor -> threshold width
+        let t = (d / span).min(1.0); // normalized position, clamped at the knee
+        // Straight line anchored at the floor (t=0 -> 0) and the knee (t=1 -> (slope-1)*span).
+        let slope_line = (low_slope - 1.0) * span * t;
+        // Bipolar bulge: 0 at both ends, peaks (4·t·(1-t) = 1) at the middle.
+        let bulge = low_curve * LOW_BULGE_MAX_DB * 4.0 * t * (1.0 - t);
+        slope_line + bulge
     }
 
     /// Full static curve, **serial**: the low shaper reshapes the level, then the compressor's
@@ -190,7 +219,7 @@ impl Compressor {
         low_slope: f32,
         low_curve: f32,
     ) -> f32 {
-        let low = Self::low_gain_db(level_db, low_slope, low_curve);
+        let low = Self::low_gain_db(level_db, threshold_db, low_slope, low_curve);
         low + Self::comp_gain_db(level_db + low, threshold_db, ratio, knee_db)
     }
 
@@ -226,8 +255,12 @@ impl Compressor {
 
         // 2) Tap positions (circular). Output is always `fixed_delay` old; the detector reads
         //    `l` samples newer than the output, i.e. `l` samples into the output's future.
-        let out_pos = (self.write_pos + self.capacity - self.fixed_delay) % self.capacity;
-        let det_pos = (self.write_pos + self.capacity - (self.fixed_delay - l)) % self.capacity;
+        // `wrap_add` instead of `%`: capacity is rarely a power of two, so a plain modulo forces
+        // an integer division here; a conditional subtract is cheaper and behaves identically
+        // given the add is always <= capacity (true for every offset computed in this function).
+        let out_pos = wrap_add(self.write_pos, self.capacity - self.fixed_delay, self.capacity);
+        let det_pos =
+            wrap_add(self.write_pos, self.capacity - (self.fixed_delay - l), self.capacity);
 
         // 3) Linked peak detector at the look-ahead tap.
         let mut peak = 0.0f32;
@@ -241,7 +274,7 @@ impl Compressor {
         //    active (regardless of mode) so switching peak<->RMS is seamless.
         self.mean_sq = self.rms_coef * self.mean_sq + (1.0 - self.rms_coef) * peak * peak;
         let detector = if set.use_rms { self.mean_sq.sqrt() } else { peak };
-        let level_db = 20.0 * (detector + LEVEL_EPS).log10();
+        let level_db = (detector + LEVEL_EPS).ln() * LOG10_GAIN_TO_DB;
         // Desired attenuation in dB, as a positive quantity.
         let target = -Self::gain_computer(
             level_db,
@@ -258,7 +291,7 @@ impl Compressor {
         self.y1 = target.max(set.release_coef * self.y1 + (1.0 - set.release_coef) * target);
         self.yl = set.attack_coef * self.yl + (1.0 - set.attack_coef) * self.y1;
 
-        let wet_gain = 10.0f32.powf((set.makeup_db - self.yl) / 20.0);
+        let wet_gain = ((set.makeup_db - self.yl) * DB_TO_GAIN_EXP).exp();
 
         // 5) Dry/wet mix (parallel compression). Both paths use the same delayed input, so the
         //    blend is phase-aligned. mix = 0 -> dry passthrough (clean bypass), mix = 1 -> wet.
@@ -269,7 +302,19 @@ impl Compressor {
         }
 
         // 6) Advance the write head.
-        self.write_pos = (self.write_pos + 1) % self.capacity;
+        self.write_pos = wrap_add(self.write_pos, 1, self.capacity);
+    }
+}
+
+/// Wrap `pos + add` into `[0, capacity)`, assuming `add <= capacity` — a conditional subtract in
+/// place of `%`, since `capacity` is rarely a power of two (so `%` costs a real integer division).
+#[inline]
+fn wrap_add(pos: usize, add: usize, capacity: usize) -> usize {
+    let sum = pos + add;
+    if sum >= capacity {
+        sum - capacity
+    } else {
+        sum
     }
 }
 
@@ -306,21 +351,22 @@ mod tests {
     }
 
     #[test]
-    fn low_shaper_is_serial_into_threshold() {
-        // Serial: the low shaper reshapes the level, then the threshold sees the shaped level.
-        // 30 dB above the -60 floor, 12 dB below threshold (hard knee, no curve).
-        let (lvl, thr) = (-30.0, -18.0);
-        // Unity slope -> just the compressor (below threshold here -> 0).
-        assert_close(Compressor::gain_computer(lvl, thr, 4.0, 0.0, 1.0, 0.0), 0.0, 1e-6);
-        // Boost (slope 2, straight) lifts -30 by 30 dB to 0 dB -> 18 dB over threshold, comp pulls
-        // back (1/4 - 1) * 18 = -13.5 -> net 30 - 13.5 = 16.5.
-        assert_close(Compressor::gain_computer(lvl, thr, 4.0, 0.0, 2.0, 0.0), 16.5, 1e-3);
+    fn low_shaper_serial_slope_and_bipolar_bulge() {
+        let thr = -18.0;
+        // Serial slope-only (no curve): boost lifts -30 by 30 dB to 0 dB -> 18 dB over threshold,
+        // comp pulls back (1/4 - 1)*18 = -13.5 -> net 16.5.
+        assert_close(Compressor::gain_computer(-30.0, thr, 4.0, 0.0, 2.0, 0.0), 16.5, 1e-3);
         // Cut (slope 0.5) -> -15 dB; shaped to -45, still below threshold -> net -15.
-        assert_close(Compressor::gain_computer(lvl, thr, 4.0, 0.0, 0.5, 0.0), -15.0, 1e-3);
-        // Curvature bounds the low gain: slope 2 + full curve saturates the boost (~9.5 dB) so it
-        // no longer crosses the threshold.
-        let g = Compressor::gain_computer(lvl, thr, 4.0, 0.0, 2.0, 1.0);
-        assert!((8.0..11.0).contains(&g), "expected bounded low boost ~9.5, got {g}");
+        assert_close(Compressor::gain_computer(-30.0, thr, 4.0, 0.0, 0.5, 0.0), -15.0, 1e-3);
+
+        // Curvature is a BIPOLAR bulge at the middle of the low region (unity slope here).
+        let mid = -39.0; // middle of [-60, -18]
+        let flat = Compressor::gain_computer(mid, thr, 4.0, 0.0, 1.0, 0.0);
+        let up = Compressor::gain_computer(mid, thr, 4.0, 0.0, 1.0, 1.0);
+        let down = Compressor::gain_computer(mid, thr, 4.0, 0.0, 1.0, -1.0);
+        assert!(up > flat && flat > down, "bipolar bulge expected: {down} < {flat} < {up}");
+        // Endpoints are unaffected by curvature (silence anchored).
+        assert_close(Compressor::gain_computer(-60.0, thr, 4.0, 0.0, 1.0, 1.0), 0.0, 1e-6);
     }
 
     #[test]
@@ -347,7 +393,7 @@ mod tests {
         // Constant 0.5 (-6.02 dBFS) into a -18 dB / 2:1 / hard-knee comp:
         // reduction = -0.5 * (−6.02 − −18) = −5.99 dB, so output ≈ 0.5 * 10^(−5.99/20).
         let mut comp = Compressor::new();
-        comp.prepare(SR, 1, MAX_LOOKAHEAD_MS);
+        comp.prepare(SR, 1, MAX_LOOKAHEAD_MS, RMS_WINDOW_DEFAULT_MS);
         let set = settings(-18.0, 2.0, 0.0);
         let mut out = [0.0f32];
         for _ in 0..SR as usize {
@@ -367,7 +413,7 @@ mod tests {
 
         fn output_rms(use_rms: bool) -> f32 {
             let mut comp = Compressor::new();
-            comp.prepare(SR, 1, MAX_LOOKAHEAD_MS);
+            comp.prepare(SR, 1, MAX_LOOKAHEAD_MS, RMS_WINDOW_DEFAULT_MS);
             let mut set = settings(-30.0, 4.0, 0.0);
             set.use_rms = use_rms;
             set.attack_coef = Compressor::time_to_coef(1.0, SR);
@@ -401,7 +447,7 @@ mod tests {
         // knob must NOT change that (this is what keeps live adjustment from renegotiating
         // latency and crashing the host).
         let mut comp = Compressor::new();
-        comp.prepare(SR, 1, 0.5); // small max so the fixed delay is quick to test
+        comp.prepare(SR, 1, 0.5, RMS_WINDOW_DEFAULT_MS); // small max so the fixed delay is quick to test
         let d = comp.latency() as usize;
         assert!(d > 0);
 
@@ -423,4 +469,65 @@ mod tests {
             }
         }
     }
+
+    /// Measure peak-to-peak gain-reduction ripple for a steady sine, with the ballistics
+    /// disabled so the gain follows the detector directly. Squaring puts a component at 2f in
+    /// the detector, so a window that does not span a cycle leaves the gain wobbling at 2f -
+    /// which is intermodulation, heard as growl on bass.
+    fn gr_ripple_db(rms_window_ms: f32, freq: f32) -> f32 {
+        let mut c = Compressor::new();
+        c.prepare(SR, 1, MAX_LOOKAHEAD_MS, rms_window_ms);
+        let set = CompressorSettings {
+            threshold_db: -40.0, ratio: 8.0, knee_db: 0.0,
+            // coef 0 = no attack/release smoothing, so yl == the detector's target.
+            attack_coef: 0.0, release_coef: 0.0,
+            makeup_db: 0.0, mix: 1.0, lookahead_samples: 0,
+            use_rms: true, low_slope: 1.0, low_curve: 0.0,
+        };
+        let mut out = [0.0f32];
+        // Settle well past the longest window under test.
+        let settle = (SR * 0.5) as usize;
+        for i in 0..settle {
+            let x = (i as f32 / SR * freq * std::f32::consts::TAU).sin();
+            c.process(&[x], &mut out, &set);
+        }
+        let (mut lo, mut hi) = (f32::MAX, f32::MIN);
+        for i in settle..settle + (SR / freq * 4.0) as usize {
+            let x = (i as f32 / SR * freq * std::f32::consts::TAU).sin();
+            c.process(&[x], &mut out, &set);
+            let gr = c.gain_reduction_db();
+            lo = lo.min(gr);
+            hi = hi.max(gr);
+        }
+        hi - lo
+    }
+
+    /// The per-band RMS windows in `lib.rs` exist to keep this ripple down; without a test the
+    /// next person to "tune" them has nothing telling them what they are for.
+    #[test]
+    fn rms_window_suppresses_low_frequency_ripple() {
+        // The LOW band's 50 ms window against the lowest content it can be asked to carry.
+        let low_band = gr_ripple_db(50.0, 30.0);
+        assert!(low_band < 1.0, "50 ms window rippled {low_band:.2} dB at 30 Hz, expected < 1 dB");
+
+        // A short window on the same signal must be visibly worse - this is what the per-band
+        // table is avoiding, and it keeps the assertion above from passing for the wrong reason.
+        let short = gr_ripple_db(5.0, 30.0);
+        assert!(
+            short > 3.0 * low_band,
+            "5 ms ({short:.2} dB) should ripple far more than 50 ms ({low_band:.2} dB)"
+        );
+
+        // Ripple must fall monotonically as the window grows.
+        let mut prev = f32::MAX;
+        for w in [5.0, 10.0, 20.0, 35.0, 50.0] {
+            let r = gr_ripple_db(w, 30.0);
+            assert!(r < prev, "ripple did not fall from the previous window at {w} ms ({r:.2} dB)");
+            prev = r;
+        }
+
+        // The HIGH band's short window is fine because nothing up there ripples.
+        let high_band = gr_ripple_db(10.0, 5_000.0);
+        assert!(high_band < 0.1, "10 ms window rippled {high_band:.2} dB at 5 kHz");
+    }
 }

src/dsp/crossover.rs

@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-3.0-or-later
 //! 3-band Linkwitz-Riley (LR4, 24 dB/oct) crossover filterbank.
 //!
 //! Each crossover splits into a low-passed band output and a high-passed remainder that feeds

src/dsp/limiter.rs

@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-3.0-or-later
 //! Look-ahead brickwall peak limiter (base-rate).
 //!
 //! Guarantees the output never exceeds the ceiling. A short fixed look-ahead lets the gain ramp
@@ -8,7 +9,7 @@
 //! Detection is stereo-linked (one gain for all channels). This stage limits **sample** peaks at
 //! the base rate; true-peak (inter-sample) limiting via oversampling is a later addition.
 
-use super::oversampler::Oversampler;
+use super::oversampler::{self, Oversampler};
 
 const MAX_CHANNELS: usize = 2;
 /// Fixed look-ahead — also this stage's constant latency contribution.
@@ -27,32 +28,118 @@ fn time_to_coef(time_ms: f32, sample_rate: f32) -> f32 {
     }
 }
 
+/// Wrap `pos + add` into `[0, capacity)`, assuming `add <= capacity` — a conditional subtract in
+/// place of `%`, since `capacity` is rarely a power of two (so `%` costs a real integer division).
+#[inline]
+fn wrap_add(pos: usize, add: usize, capacity: usize) -> usize {
+    let sum = pos + add;
+    if sum >= capacity {
+        sum - capacity
+    } else {
+        sum
+    }
+}
+
+/// O(1)-amortized fixed-window sliding maximum (the classic monotonic-deque algorithm), in place
+/// of rescanning the whole window every sample. Values are pushed one at a time; each push returns
+/// the max over the last `window` pushes (inclusive of the one just pushed).
+///
+/// Backed by two preallocated ring buffers sized to `window` (never grows past that: entries are
+/// evicted once their age reaches `window`, and a strictly-decreasing run of un-evicted entries
+/// still ages out within `window` pushes) — so `push` never allocates, keeping it RT-safe.
+struct SlidingMax {
+    val: Vec<f32>,
+    seq: Vec<u64>,
+    cap: usize,
+    head: usize,
+    len: usize,
+    next_seq: u64,
+}
+
+impl SlidingMax {
+    fn new() -> Self {
+        Self { val: Vec::new(), seq: Vec::new(), cap: 0, head: 0, len: 0, next_seq: 0 }
+    }
+
+    fn prepare(&mut self, window: usize) {
+        self.cap = window.max(1);
+        self.val = vec![0.0; self.cap];
+        self.seq = vec![0; self.cap];
+        self.reset();
+    }
+
+    fn reset(&mut self) {
+        self.head = 0;
+        self.len = 0;
+        self.next_seq = 0;
+    }
+
+    /// Push a new value; return the maximum over the last `cap` pushes (including this one).
+    fn push(&mut self, value: f32) -> f32 {
+        let t = self.next_seq;
+
+        // Values can never be the max while the new one is still in the window, so drop them.
+        while self.len > 0 {
+            let back = (self.head + self.len - 1) % self.cap;
+            if self.val[back] <= value {
+                self.len -= 1;
+            } else {
+                break;
+            }
+        }
+
+        let back = (self.head + self.len) % self.cap;
+        self.val[back] = value;
+        self.seq[back] = t;
+        self.len += 1;
+
+        // Evict entries that have aged out of the window.
+        while self.seq[self.head] + self.cap as u64 <= t {
+            self.head = (self.head + 1) % self.cap;
+            self.len -= 1;
+        }
+
+        self.next_seq = t + 1;
+        self.val[self.head]
+    }
+}
+
 pub struct Limiter {
     /// Per-channel audio delay ring.
     delay: Vec<Vec<f32>>,
-    /// Linked `|x|` history, same length as the delay ring (for the sliding maximum).
-    peaks: Vec<f32>,
+    /// O(1)-amortized sliding-window maximum over the linked `|x|` history (replaces an O(window)
+    /// full-rescan every sample).
+    sliding_max: SlidingMax,
     capacity: usize,
     write_pos: usize,
     fixed_delay: usize,
     /// Current smoothed gain (<= 1).
     gain: f32,
     attack_coef: f32,
+    /// `10^(-TRUE_PEAK_MARGIN_DB/20)`, precomputed once (the margin is a fixed constant, so
+    /// there's no reason to recompute this `powf` on every sample).
+    margin_gain: f32,
     /// 4× interpolator for true-peak (inter-sample) detection.
     oversampler: Oversampler,
+    /// Sliding max of the sample peak over the interpolator's FIR support, which bounds what
+    /// its next evaluation can possibly return. Lets `process` skip the evaluation entirely
+    /// when that bound is already under the ceiling.
+    support_max: SlidingMax,
 }
 
 impl Default for Limiter {
     fn default() -> Self {
         Self {
             delay: Vec::new(),
-            peaks: Vec::new(),
+            sliding_max: SlidingMax::new(),
             capacity: 0,
             write_pos: 0,
             fixed_delay: 0,
             gain: 1.0,
             attack_coef: 0.0,
+            margin_gain: 1.0,
             oversampler: Oversampler::new(),
+            support_max: SlidingMax::new(),
         }
     }
 }
@@ -67,9 +154,11 @@ impl Limiter {
         self.fixed_delay = (LOOKAHEAD_MS * 0.001 * sample_rate).ceil() as usize;
         self.capacity = self.fixed_delay + 1;
         self.attack_coef = time_to_coef(ATTACK_MS, sample_rate);
+        self.margin_gain = 10.0f32.powf(-TRUE_PEAK_MARGIN_DB / 20.0);
         let channels = num_channels.clamp(1, MAX_CHANNELS);
         self.delay = vec![vec![0.0; self.capacity]; channels];
-        self.peaks = vec![0.0; self.capacity];
+        self.sliding_max.prepare(self.capacity);
+        self.support_max.prepare(oversampler::SUPPORT_LEN);
         self.oversampler.prepare(channels);
         self.reset();
     }
@@ -78,7 +167,8 @@ impl Limiter {
         for ch in &mut self.delay {
             ch.iter_mut().for_each(|s| *s = 0.0);
         }
-        self.peaks.iter_mut().for_each(|p| *p = 0.0);
+        self.sliding_max.reset();
+        self.support_max.reset();
         self.oversampler.reset();
         self.write_pos = 0;
         self.gain = 1.0;
@@ -107,24 +197,37 @@ impl Limiter {
         for &x in &input[..n] {
             sample_peak = sample_peak.max(x.abs());
         }
-        let peak = sample_peak.max(self.oversampler.max_true_peak(&input[..n]));
 
         // Target a hair below the ceiling so the (slightly under-read) true peak stays under it.
-        let target_ceiling = ceiling * 10.0f32.powf(-TRUE_PEAK_MARGIN_DB / 20.0);
+        let target_ceiling = ceiling * self.margin_gain;
+
+        // The polyphase evaluation is ~PHASES*TAPS multiply-adds per channel and runs on every
+        // sample, which makes it the most expensive single thing in the chain. It is also
+        // skippable: the interpolator is linear, so over its FIR support
+        //     |true peak| <= peak_gain * max|history|
+        // and when that bound sits under the ceiling the true peak provably cannot reach it.
+        // The limiter's target would be 1.0 for this sample either way, so feeding the sample
+        // peak instead cannot change the outcome - `sliding_max` still sees any genuinely loud
+        // neighbour through that neighbour's own evaluation.
+        //
+        // The history must still be fed on every sample, or later evaluations read holes.
+        self.oversampler.push(&input[..n]);
+        let support_max = self.support_max.push(sample_peak);
+        let peak = if support_max * self.oversampler.peak_gain() <= target_ceiling {
+            sample_peak
+        } else {
+            sample_peak.max(self.oversampler.evaluate(n))
+        };
 
         // Write into the ring.
         for ch in 0..n {
             self.delay[ch][self.write_pos] = input[ch];
         }
-        self.peaks[self.write_pos] = peak;
 
         // Sliding maximum over the look-ahead window (= the whole ring). Because the oldest sample
         // (the one we output now) is in this window, `ceiling / window_max` applied to it can never
         // exceed the ceiling, and the gain has pre-dropped for any louder sample still to come.
-        let mut window_max = 0.0f32;
-        for &p in &self.peaks {
-            window_max = window_max.max(p);
-        }
+        let window_max = self.sliding_max.push(peak);
         let target = if window_max > target_ceiling {
             target_ceiling / window_max
         } else {
@@ -139,12 +242,14 @@ impl Limiter {
         };
 
         // Output the delayed sample, clamped to the ceiling as the hard guarantee.
-        let out_pos = (self.write_pos + 1) % self.capacity; // oldest sample = fixed_delay ago
+        // Conditional subtract instead of `%`: capacity is rarely a power of two, and the add
+        // here (1) is always <= capacity, so a plain compare-and-subtract is enough.
+        let out_pos = wrap_add(self.write_pos, 1, self.capacity); // oldest sample = fixed_delay ago
         for ch in 0..n {
             output[ch] = (self.delay[ch][out_pos] * self.gain).clamp(-ceiling, ceiling);
         }
 
-        self.write_pos = (self.write_pos + 1) % self.capacity;
+        self.write_pos = wrap_add(self.write_pos, 1, self.capacity);
     }
 }
 
@@ -159,6 +264,31 @@ mod tests {
         time_to_coef(50.0, SR)
     }
 
+    #[test]
+    fn sliding_max_matches_naive_full_rescan() {
+        // A small xorshift-ish PRNG (no extra deps) exercising both rising and falling runs.
+        let mut state = 0x1234_5678u32;
+        let mut next = || {
+            state ^= state << 13;
+            state ^= state >> 17;
+            state ^= state << 5;
+            (state % 1000) as f32 / 1000.0
+        };
+
+        let window = 7usize;
+        let mut sm = SlidingMax::new();
+        sm.prepare(window);
+        let mut history: Vec<f32> = Vec::new();
+
+        for _ in 0..2_000 {
+            let v = next();
+            history.push(v);
+            let start = history.len().saturating_sub(window);
+            let expected = history[start..].iter().cloned().fold(0.0f32, f32::max);
+            assert_eq!(sm.push(v), expected);
+        }
+    }
+
     #[test]
     fn never_exceeds_ceiling_on_spikes() {
         // Mostly silence with occasional large spikes — output must never exceed the ceiling.

src/dsp/mod.rs

@@ -1,4 +1,5 @@
-//! DSP building blocks for Codename 206.
+// SPDX-License-Identifier: GPL-3.0-or-later
+//! DSP building blocks for Bari 206.
 //!
 //! The signal chain: a `crossover` filterbank splits into bands, each band (plus the summed
 //! 'All' channel) runs a `compressor`, and a `limiter` (with a true-peak `oversampler` detector)

src/dsp/oversampler.rs

@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-3.0-or-later
 //! 4× polyphase interpolation for **true-peak (inter-sample) detection only**.
 //!
 //! A band-limited signal can overshoot its sample values between samples, so the digital sample
@@ -16,6 +17,9 @@
 
 const PHASES: usize = 4;
 const TAPS_PER_PHASE: usize = 12;
+/// Length of the FIR support, i.e. how many past input frames an evaluation reads. A caller
+/// bounding the true peak needs the max over exactly this many frames.
+pub const SUPPORT_LEN: usize = TAPS_PER_PHASE;
 const MAX_CHANNELS: usize = 2;
 
 /// Build the normalised polyphase coefficients: a windowed-sinc prototype split into `PHASES`
@@ -52,17 +56,32 @@ fn build_coefficients() -> [[f32; TAPS_PER_PHASE]; PHASES] {
     coeffs
 }
 
+/// Largest L1 norm across phases: `max_phase sum |c|`. Bounds the interpolator's output for a
+/// bounded input, which is what makes the [`Oversampler::peak_gain`] early-out sound.
+fn build_peak_gain(coeffs: &[[f32; TAPS_PER_PHASE]; PHASES]) -> f32 {
+    coeffs
+        .iter()
+        .map(|row| row.iter().map(|c| c.abs()).sum::<f32>())
+        .fold(0.0f32, f32::max)
+}
+
 pub struct Oversampler {
     coeffs: [[f32; TAPS_PER_PHASE]; PHASES],
     /// Per-channel circular history of the last `TAPS_PER_PHASE` input samples.
     history: Vec<[f32; TAPS_PER_PHASE]>,
     pos: usize,
+    /// Largest L1 norm across the phases. Since every interpolated sample is a dot product of
+    /// one phase with the history, `|interpolated| <= peak_gain * max|history|` - a hard bound,
+    /// which lets a caller prove the true peak cannot reach a ceiling without evaluating it.
+    peak_gain: f32,
 }
 
 impl Default for Oversampler {
     fn default() -> Self {
+        let coeffs = build_coefficients();
         Self {
-            coeffs: build_coefficients(),
+            peak_gain: build_peak_gain(&coeffs),
+            coeffs,
             history: Vec::new(),
             pos: 0,
         }
@@ -89,30 +108,63 @@ impl Oversampler {
 
     /// Feed one input frame; return the maximum inter-sample magnitude across all channels and the
     /// 4× grid (the reconstructed samples are not kept).
-    pub fn max_true_peak(&mut self, input: &[f32]) -> f32 {
+    /// Upper bound on `|interpolated|` for an input bounded by 1.0. See [`Self::peak_gain`].
+    #[inline(always)]
+    pub fn peak_gain(&self) -> f32 {
+        self.peak_gain
+    }
+
+    /// Feed one input frame into the history. Cheap - a write per channel plus a counter.
+    /// Must be called for EVERY frame even when [`Self::evaluate`] is skipped, or the FIR
+    /// history develops holes and later evaluations read stale samples.
+    #[inline]
+    pub fn push(&mut self, input: &[f32]) {
         let n = input.len().min(self.history.len());
         let slot = self.pos % TAPS_PER_PHASE;
         for ch in 0..n {
             self.history[ch][slot] = input[ch];
         }
+        self.pos += 1;
+    }
+
+    /// The actual polyphase evaluation: `PHASES * TAPS_PER_PHASE` multiply-adds per channel.
+    /// This is the expensive half, and the only half a caller can skip.
+    #[inline]
+    pub fn evaluate(&self, channels: usize) -> f32 {
+        let n = channels.min(self.history.len());
+        // The tap index only depends on `pos` and `k`, not on `phase` or `ch` - hoist it out of
+        // those loops instead of recomputing (and re-dividing) it PHASES*MAX_CHANNELS times over.
+        // `pos` already advanced past the newest sample in push(), hence the -1.
+        let base = self.pos + TAPS_PER_PHASE - 1;
+        let mut idx = [0usize; TAPS_PER_PHASE];
+        for (k, slot) in idx.iter_mut().enumerate() {
+            // k = 0 is the newest sample, increasing k goes back in time.
+            *slot = (base - k) % TAPS_PER_PHASE;
+        }
 
         let mut peak = 0.0f32;
         for ch in 0..n {
             let hist = &self.history[ch];
             for phase in &self.coeffs {
                 let mut acc = 0.0f32;
-                for (k, &c) in phase.iter().enumerate() {
-                    // k = 0 is the newest sample, increasing k goes back in time.
-                    let idx = (self.pos + TAPS_PER_PHASE - k) % TAPS_PER_PHASE;
-                    acc += c * hist[idx];
+                for (&c, &i) in phase.iter().zip(idx.iter()) {
+                    acc += c * hist[i];
                 }
                 peak = peak.max(acc.abs());
             }
         }
-
-        self.pos += 1;
         peak
     }
+
+    /// Push a frame and evaluate it unconditionally. The real path splits these so the
+    /// evaluation can be skipped (see `Limiter::process`); this is kept for tests that want
+    /// the true peak of every frame regardless of any ceiling.
+    #[cfg(test)]
+    pub fn max_true_peak(&mut self, input: &[f32]) -> f32 {
+        let n = input.len().min(self.history.len());
+        self.push(input);
+        self.evaluate(n)
+    }
 }
 
 #[cfg(test)]
@@ -146,4 +198,38 @@ mod tests {
         }
         assert!((last - 0.5).abs() < 0.02, "amplitude not preserved: {last}");
     }
+
+    /// The early-out in `Limiter::process` is only sound if `evaluate()` can never exceed
+    /// `peak_gain * max|history|`. Assert that directly against adversarial input - full-scale
+    /// square waves and alternating impulses maximise the interpolator's overshoot.
+    #[test]
+    fn evaluate_never_exceeds_peak_gain_bound() {
+        let mut os = Oversampler::default();
+        os.prepare(2);
+        let mut rng: u32 = 0xC0FF_EE01;
+        let mut worst_ratio = 0.0f32;
+        for i in 0..20_000 {
+            rng = rng.wrapping_mul(1_664_525).wrapping_add(1_013_904_223);
+            // Mix of adversarial shapes: alternating full scale, impulses, and noise.
+            let x = match i % 3 {
+                0 => if (i / 3) % 2 == 0 { 1.0 } else { -1.0 },
+                1 => if i % 97 == 0 { 1.0 } else { 0.0 },
+                _ => (rng >> 8) as f32 / (1 << 23) as f32 - 1.0,
+            };
+            let frame = [x, -x];
+            os.push(&frame);
+            let got = os.evaluate(2);
+            // Bound uses the max over the FIR support, which for these inputs is at most 1.0.
+            let bound = os.peak_gain() * 1.0;
+            assert!(
+                got <= bound + 1e-4,
+                "evaluate() = {got} exceeded peak_gain bound {bound} at i={i}"
+            );
+            if bound > 0.0 {
+                worst_ratio = worst_ratio.max(got / bound);
+            }
+        }
+        // Sanity: the bound must be reachable enough to be useful, not vacuously huge.
+        assert!(worst_ratio > 0.3, "bound looks far too loose (worst ratio {worst_ratio})");
+    }
 }

src/editor/crossover.rs

@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-3.0-or-later
 //! Draggable crossover handles — replaces the two plain crossover sliders.
 //!
 //! A horizontal log-frequency strip split into LOW / MID / HIGH by two draggable handles, plus a
@@ -9,7 +10,8 @@ use nih_plug_egui::egui::{
     self, pos2, vec2, Align2, Color32, CornerRadius, DragValue, FontId, Painter, Rect, Sense, Stroke,
 };
 
-use crate::params::Codename206Params;
+use crate::params::Bari206Params;
+use super::palette;
 
 /// Height of the handle strip.
 const GRAPH_H: f32 = 54.0;
@@ -29,7 +31,7 @@ fn fmt_hz(hz: f32) -> String {
     }
 }
 
-pub(super) fn draw(ui: &mut egui::Ui, params: &Codename206Params, setter: &ParamSetter) {
+pub(super) fn draw(ui: &mut egui::Ui, params: &Bari206Params, setter: &ParamSetter) {
     let lo = params.crossover_low_hz.value();
     let hi = params.crossover_high_hz.value();
     // Each param's own min/max (normalized 0/1 map to the range ends).
@@ -54,19 +56,19 @@ pub(super) fn draw(ui: &mut egui::Ui, params: &Codename206Params, setter: &Param
     let xhi = x_for(hi);
 
     // Three band regions.
-    p.rect_filled(Rect::from_min_max(pos2(left, top), pos2(xlo, bottom)), CornerRadius::ZERO, Color32::from_rgb(28, 38, 52));
-    p.rect_filled(Rect::from_min_max(pos2(xlo, top), pos2(xhi, bottom)), CornerRadius::ZERO, Color32::from_rgb(30, 48, 36));
-    p.rect_filled(Rect::from_min_max(pos2(xhi, top), pos2(right, bottom)), CornerRadius::ZERO, Color32::from_rgb(52, 38, 30));
+    p.rect_filled(Rect::from_min_max(pos2(left, top), pos2(xlo, bottom)), CornerRadius::ZERO, palette::CHANNELS[0].strip);
+    p.rect_filled(Rect::from_min_max(pos2(xlo, top), pos2(xhi, bottom)), CornerRadius::ZERO, palette::CHANNELS[1].strip);
+    p.rect_filled(Rect::from_min_max(pos2(xhi, top), pos2(right, bottom)), CornerRadius::ZERO, palette::CHANNELS[2].strip);
 
     let band_label = |cx: f32, t: &str| {
-        p.text(pos2(cx, top + 2.0), Align2::CENTER_TOP, t, FontId::proportional(11.0), Color32::from_gray(160));
+        p.text(pos2(cx, top + 2.0), Align2::CENTER_TOP, t, FontId::proportional(11.0), palette::TEXT);
     };
     band_label((left + xlo) * 0.5, "LOW");
     band_label((xlo + xhi) * 0.5, "MID");
     band_label((xhi + right) * 0.5, "HIGH");
 
-    handle(ui, &p, setter, "xover_lo", xlo, lo, &params.crossover_low_hz, lo_min, lo_upper, left, width, top, bottom, Color32::from_rgb(120, 170, 230));
-    handle(ui, &p, setter, "xover_hi", xhi, hi, &params.crossover_high_hz, hi_lower, hi_max, left, width, top, bottom, Color32::from_rgb(230, 150, 120));
+    handle(ui, &p, setter, "xover_lo", xlo, lo, &params.crossover_low_hz, lo_min, lo_upper, left, width, top, bottom, palette::CHANNELS[0].handle);
+    handle(ui, &p, setter, "xover_hi", xhi, hi, &params.crossover_high_hz, hi_lower, hi_max, left, width, top, bottom, palette::CHANNELS[2].handle);
 
     // Number boxes (double-click to type). Clamped to the same dynamic limits.
     ui.horizontal(|ui| {
@@ -128,9 +130,9 @@ fn handle(
         setter.end_set_parameter(param);
     }
 
-    let col = if resp.dragged() || resp.hovered() { Color32::WHITE } else { color };
-    p.line_segment([pos2(x, top), pos2(x, bottom)], Stroke::new(2.0, col));
-    p.text(pos2(x, bottom - 1.0), Align2::CENTER_BOTTOM, fmt_hz(hz), FontId::proportional(10.0), Color32::from_gray(220));
+    let col = if resp.dragged() || resp.hovered() { palette::TEXT_HOVER } else { color };
+    p.line_segment([pos2(x, top), pos2(x, bottom)], Stroke::new(2.0_f32, col));
+    p.text(pos2(x, bottom - 1.0), Align2::CENTER_BOTTOM, fmt_hz(hz), FontId::proportional(10.0), palette::TEXT_BRIGHT);
 }
 
 /// Set a param to `value` clamped to `[min, max]`, wrapped in its own gesture (for the number box).

src/editor/gain_curve.rs

@@ -1,19 +1,24 @@
-//! Static gain-curve display (visualisation only): output level vs input level for the channel
-//! currently selected in the plot. Plots the full channel transfer for the wet path:
-//! `out = (in + pre_gain) + gain_reduction(in + pre_gain) + makeup`. Mix is not folded in (the
-//! curve shows the wet/100% path, matching the GR-meter convention); output is clamped at 0 dBFS.
+// SPDX-License-Identifier: GPL-3.0-or-later
+//! Static gain-curve display: output level vs input level for the channel currently selected in
+//! the plot. Plots the wet transfer `out = (in + pre_gain) + gain_reduction(...) + makeup` (mix not
+//! folded in; output clamped at 0 dBFS), plus a live **operating-point fill** under the curve up to
+//! the channel's current input level — its right edge rides the curve (width = input, height = out).
 
-use nih_plug_egui::egui::{self, pos2, vec2, Align2, Color32, CornerRadius, FontId, Sense, Stroke};
+use nih_plug::prelude::util;
+use nih_plug_egui::egui::{self, pos2, vec2, Align2, CornerRadius, FontId, Sense, Stroke};
+use std::sync::atomic::Ordering;
 
 use crate::dsp::compressor::Compressor;
-use crate::params::Codename206Params;
+use crate::meters::Meters;
+use crate::params::Bari206Params;
+use super::palette;
 
 /// Side length of the square plot.
 const CURVE_SIZE: f32 = 150.0;
 /// dB extent of both axes (bottom/left = FLOOR_DB, top/right = 0 dBFS).
 const FLOOR_DB: f32 = -60.0;
 
-pub(super) fn draw(ui: &mut egui::Ui, params: &Codename206Params, selected: usize) {
+pub(super) fn draw(ui: &mut egui::Ui, params: &Bari206Params, selected: usize, meters: &Meters) {
     let labels = ["LOW", "MID", "HIGH", "ALL"];
     let ch = selected.min(3);
     let cp = match ch {
@@ -33,7 +38,7 @@ pub(super) fn draw(ui: &mut egui::Ui, params: &Codename206Params, selected: usiz
     ui.label(format!("Curve: {}", labels[ch]));
     let (rect, _) = ui.allocate_exact_size(vec2(CURVE_SIZE, CURVE_SIZE), Sense::hover());
     let p = ui.painter_at(rect);
-    p.rect_filled(rect, CornerRadius::ZERO, Color32::from_rgb(16, 16, 20));
+    p.rect_filled(rect, CornerRadius::ZERO, palette::SURFACE);
 
     let inset = 2.0;
     let (left, right, top, bottom) =
@@ -43,11 +48,18 @@ pub(super) fn draw(ui: &mut egui::Ui, params: &Codename206Params, selected: usiz
     let x_for = |db: f32| left + (db - FLOOR_DB) / -FLOOR_DB * w;
     let y_for = |db: f32| bottom - (db - FLOOR_DB) / -FLOOR_DB * h;
 
+    // -6 dBFS reference lines on both axes.
+    let g6 = palette::GRID_FAINT;
+    let x6 = x_for(-6.0);
+    let y6 = y_for(-6.0);
+    p.line_segment([pos2(x6, top), pos2(x6, bottom)], Stroke::new(1.0_f32, g6));
+    p.line_segment([pos2(left, y6), pos2(right, y6)], Stroke::new(1.0_f32, g6));
+
     // Unity reference (out = in), bottom-left to top-right.
-    p.line_segment([pos2(left, bottom), pos2(right, top)], Stroke::new(1.0, Color32::from_gray(45)));
+    p.line_segment([pos2(left, bottom), pos2(right, top)], Stroke::new(1.0_f32, palette::GRID));
     // Threshold marker on the input axis — shifted left by pre-gain (the comp sees in + pre).
     let tx = x_for((threshold - pre).clamp(FLOOR_DB, 0.0));
-    p.line_segment([pos2(tx, top), pos2(tx, bottom)], Stroke::new(1.0, Color32::from_rgb(80, 60, 45)));
+    p.line_segment([pos2(tx, top), pos2(tx, bottom)], Stroke::new(1.0_f32, palette::THRESHOLD_LINE));
 
     // Full wet transfer: drive into the comp, then makeup. (Mix not folded in.)
     let n = 96;
@@ -59,9 +71,38 @@ pub(super) fn draw(ui: &mut egui::Ui, params: &Codename206Params, selected: usiz
         let out_db = (driven + gr + makeup).clamp(FLOOR_DB, 0.0);
         pts.push(pos2(x_for(in_db), y_for(out_db)));
     }
-    p.add(egui::Shape::line(pts, Stroke::new(1.6, Color32::from_rgb(120, 200, 160))));
+    // Operating-point fill: shade under the curve from the floor up to the current input level.
+    let driven_now = util::gain_to_db(meters.input_level[ch].load(Ordering::Relaxed));
+    let ext_in = (driven_now - pre).clamp(FLOOR_DB, 0.0); // external input -> curve x
+    let x_now = x_for(ext_in);
+    let fill_col = palette::with_alpha(palette::CURVE, 45);
+    for seg in pts.windows(2) {
+        let a = seg[0];
+        let mut b = seg[1];
+        if a.x >= x_now {
+            break;
+        }
+        if b.x > x_now {
+            let f = ((x_now - a.x) / (b.x - a.x)).clamp(0.0, 1.0); // clip the last quad at x_now
+            b = pos2(x_now, a.y + (b.y - a.y) * f);
+        }
+        p.add(egui::Shape::convex_polygon(
+            vec![pos2(a.x, bottom), a, b, pos2(b.x, bottom)],
+            fill_col,
+            Stroke::NONE,
+        ));
+    }
 
-    // Corner dB ticks.
-    p.text(pos2(left + 1.0, top + 1.0), Align2::LEFT_TOP, "0", FontId::proportional(9.0), Color32::from_gray(90));
-    p.text(pos2(left + 1.0, bottom - 1.0), Align2::LEFT_BOTTOM, "-60", FontId::proportional(9.0), Color32::from_gray(90));
+    p.add(egui::Shape::line(pts, Stroke::new(1.6_f32, palette::CURVE)));
+
+    // Operating-point dot, on the curve at the current input.
+    let driven = ext_in + pre;
+    let gr = Compressor::gain_computer(driven, threshold, ratio, knee, low_slope, low_curve);
+    let out_op = (driven + gr + makeup).clamp(FLOOR_DB, 0.0);
+    p.circle_filled(pos2(x_now, y_for(out_op)), 3.0, palette::OPERATING_POINT);
+
+    // Corner dB ticks + the -6 dB reference.
+    p.text(pos2(left + 1.0, top + 1.0), Align2::LEFT_TOP, "0", FontId::proportional(9.0), palette::TEXT_DIM);
+    p.text(pos2(left + 1.0, bottom - 1.0), Align2::LEFT_BOTTOM, "-60", FontId::proportional(9.0), palette::TEXT_DIM);
+    p.text(pos2(x6 + 2.0, bottom - 1.0), Align2::LEFT_BOTTOM, "-6", FontId::proportional(9.0), palette::TEXT_DIM);
 }

src/editor/meter.rs

@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-3.0-or-later
 //! Per-channel level + gain-reduction meters, each with its own latching ceiling/over lamp.
 //!
 //! Each channel is a `|L | GR | R|` cluster (output level left/right, mono gain reduction in the
@@ -14,6 +15,7 @@ use std::sync::atomic::Ordering;
 
 use super::METER_FLOOR_DB;
 use crate::meters::{Meters, NUM_CHANNELS};
+use super::palette;
 
 /// Full-scale of the gain-reduction bar (fills downward from the top).
 const GR_FULL_DB: f32 = 24.0;
@@ -46,7 +48,7 @@ pub(super) fn draw(ui: &mut egui::Ui, meters: &Meters, state: &mut MeterState) {
     let (rect, _) =
         ui.allocate_exact_size(vec2(ui.available_width(), METER_PANEL_H), Sense::hover());
     let p = ui.painter_at(rect);
-    p.rect_filled(rect, CornerRadius::ZERO, Color32::from_rgb(20, 20, 24));
+    p.rect_filled(rect, CornerRadius::ZERO, palette::SURFACE_RAISED);
 
     let top = rect.top() + 22.0; // leave a row at the top for the lamps
     let bottom = rect.bottom() - 18.0; // and a row at the bottom for the labels
@@ -57,6 +59,22 @@ pub(super) fn draw(ui: &mut egui::Ui, meters: &Meters, state: &mut MeterState) {
 
     for i in 0..NUM_CHANNELS {
         let cell_left = rect.left() + i as f32 * cell_w;
+
+        // Channel chrome. The four clusters are otherwise identical and told apart only by the
+        // label underneath, which is the one place channel identity is hardest to read. A dark
+        // wash behind the cell plus an accent rule under the bars fixes that without touching
+        // the bars themselves - see `palette`: hue is chrome, functional colour is data.
+        let cell = Rect::from_min_max(
+            pos2(cell_left + 1.0, rect.top()),
+            pos2(cell_left + cell_w - 1.0, rect.bottom()),
+        );
+        p.rect_filled(cell, CornerRadius::ZERO, palette::CHANNELS[i].chrome);
+        p.rect_filled(
+            Rect::from_min_max(pos2(cell.left(), bottom + 2.0), pos2(cell.right(), bottom + 4.0)),
+            CornerRadius::ZERO,
+            palette::CHANNELS[i].edge,
+        );
+
         let group_w = bar_w * 3.0 + gap * 2.0;
         let bx = cell_left + (cell_w - group_w) * 0.5;
 
@@ -70,16 +88,16 @@ pub(super) fn draw(ui: &mut egui::Ui, meters: &Meters, state: &mut MeterState) {
         let gr_db = meters.gain_reduction_db[i].load(Ordering::Relaxed);
         let gr_frac = (gr_db / GR_FULL_DB).clamp(0.0, 1.0);
 
-        v_bar(&p, bx, bar_w, top, bottom, l_frac, level_color(l_db), false);
-        v_bar(&p, bx + bar_w + gap, bar_w, top, bottom, gr_frac, Color32::from_rgb(240, 150, 60), true);
-        v_bar(&p, bx + 2.0 * (bar_w + gap), bar_w, top, bottom, r_frac, level_color(r_db), false);
+        v_bar(&p, bx, bar_w, top, bottom, l_frac, palette::level_color(l_db), false);
+        v_bar(&p, bx + bar_w + gap, bar_w, top, bottom, gr_frac, palette::SIGNAL_GR, true);
+        v_bar(&p, bx + 2.0 * (bar_w + gap), bar_w, top, bottom, r_frac, palette::level_color(r_db), false);
 
         p.text(
             pos2(cell_left + cell_w * 0.5, rect.bottom() - 2.0),
             Align2::CENTER_BOTTOM,
             labels[i],
             FontId::proportional(12.0),
-            Color32::from_gray(200),
+            palette::TEXT_BRIGHT,
         );
 
         // Per-channel lamp: latch on output reaching 0 dBFS; the ALL channel also latches when the
@@ -108,9 +126,9 @@ pub(super) fn draw(ui: &mut egui::Ui, meters: &Meters, state: &mut MeterState) {
             }
         }
         let lamp = if state.ceiling_trigger[i].is_some() {
-            Color32::from_rgb(255, 40, 40)
+            palette::LAMP_ON
         } else {
-            Color32::from_rgb(40, 12, 12)
+            palette::LAMP_OFF
         };
         p.circle_filled(lamp_center, 5.0, lamp);
     }
@@ -119,7 +137,7 @@ pub(super) fn draw(ui: &mut egui::Ui, meters: &Meters, state: &mut MeterState) {
 /// Draw a vertical bar within `[top, bottom]`. `frac` is 0..1; `from_top` fills downward from the
 /// top (gain reduction) instead of upward from the bottom (level).
 fn v_bar(p: &Painter, x: f32, w: f32, top: f32, bottom: f32, frac: f32, fill: Color32, from_top: bool) {
-    let track = Color32::from_rgb(34, 34, 40);
+    let track = palette::TRACK;
     p.rect_filled(Rect::from_min_max(pos2(x, top), pos2(x + w, bottom)), CornerRadius::ZERO, track);
 
     let h = (bottom - top) * frac.clamp(0.0, 1.0);
@@ -130,14 +148,3 @@ fn v_bar(p: &Painter, x: f32, w: f32, top: f32, bottom: f32, frac: f32, fill: Co
     };
     p.rect_filled(filled, CornerRadius::ZERO, fill);
 }
-
-/// Level-bar colour: green below -6 dB, yellow approaching, red near 0 dBFS.
-fn level_color(db: f32) -> Color32 {
-    if db >= -1.0 {
-        Color32::from_rgb(235, 70, 60)
-    } else if db >= -6.0 {
-        Color32::from_rgb(230, 200, 70)
-    } else {
-        Color32::from_rgb(90, 200, 110)
-    }
-}

src/editor/mod.rs

@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-3.0-or-later
 //! egui editor: assembly + control layout.
 //!
 //! The aggregator. Builds the editor window and lays out the heading, the meter panel
@@ -16,12 +17,13 @@ use nih_plug_egui::{
 use std::sync::Arc;
 
 use crate::meters::Meters;
-use crate::params::{Codename206Params, CompressorParams};
-use crate::Codename206;
+use crate::params::{Bari206Params, CompressorParams};
+use crate::Bari206;
 
 mod crossover;
 mod gain_curve;
 mod meter;
+mod palette;
 mod plot;
 
 /// Bottom of the dB scale shared by the meters and the plot (top is 0 dBFS).
@@ -35,12 +37,12 @@ struct EditorState {
 }
 
 /// Build the plugin editor over shared handles to the params and meter state.
-pub(crate) fn create(params: Arc<Codename206Params>, meters: Arc<Meters>) -> Option<Box<dyn Editor>> {
+pub(crate) fn create(params: Arc<Bari206Params>, meters: Arc<Meters>) -> Option<Box<dyn Editor>> {
     let egui_state = params.editor_state.clone();
     create_egui_editor(
         params.editor_state.clone(),
         EditorState::default(),
-        |_, _| {},
+        |egui_ctx, _| palette::apply_visuals(egui_ctx),
         move |egui_ctx, setter, state| {
             // Keep frames coming so the meters animate and the lamp can time out while open.
             egui_ctx.request_repaint();
@@ -78,13 +80,13 @@ pub(crate) fn create(params: Arc<Codename206Params>, meters: Arc<Meters>) -> Opt
                 .min_size(Vec2::new(480.0, 320.0))
                 .show(egui_ctx, egui_state.as_ref(), |ui| {
                     egui::ScrollArea::vertical().show(ui, |ui| {
-                        ui.heading(Codename206::NAME);
+                        ui.heading(Bari206::NAME);
                         meter::draw(ui, &meters, &mut state.meter);
                         ui.separator();
                         // Gain curve (left, square) beside the scrolling plot (right, fills the rest).
                         let selected = state.plot.selected;
                         ui.horizontal_top(|ui| {
-                            ui.vertical(|ui| gain_curve::draw(ui, &params, selected));
+                            ui.vertical(|ui| gain_curve::draw(ui, &params, selected, &meters));
                             ui.vertical(|ui| plot::draw(ui, &meters, &mut state.plot));
                         });
                         ui.separator();

src/editor/palette.rs

@@ -0,0 +1,265 @@
+// SPDX-License-Identifier: GPL-3.0-or-later
+//! The plugin's colour system.
+//!
+//! # The rule
+//!
+//! **Channel hue is chrome; functional colour is data.** Before picking a colour, ask what the
+//! pixel is for. Is it showing a *value* — a level, a reduction, a clip? Then it comes from the
+//! functional palette, and it means the same thing in every channel. Is it telling you *which
+//! channel you are looking at*? Then it comes from that channel's hue, and it never touches the
+//! data itself.
+//!
+//! This is what keeps the two systems from fighting. An earlier version of this UI used blue,
+//! green and orange for LOW/MID/HIGH in the crossover *and* for input/output/gain-reduction in
+//! the scope, so orange meant "the high band" in one widget and "gain reduction" in the one next
+//! to it.
+//!
+//! # The two tiers
+//!
+//! 1. **Seeds** — the short, hand-picked list in the first half of this file. This is the part
+//!    you edit. Everything else is derived from it.
+//! 2. **Derived** — [`Channel`] palettes built from a hue by [`channel`]. Change a hue and every
+//!    tint, edge and strip using it moves with it.
+//!
+//! All derivation is `const fn`, so the whole table is computed at compile time and costs nothing
+//! at runtime. That is also why it uses plain HSV rather than `ecolor::Hsva`, whose conversion is
+//! not `const`.
+//!
+//! # Editing this file
+//!
+//! * To recolour a channel, change one `HUE_*` constant. Never hand-edit a derived value.
+//! * To retune the meter's headroom ramp, edit [`LEVEL_OK`] / [`LEVEL_WARN`] / [`LEVEL_HOT`] and
+//!   the thresholds in [`level_color`]. Both are deliberately literal rather than interpolated,
+//!   so you can set each one by eye without fighting a gradient.
+//! * To change how loudly channel identity reads, edit the `(saturation, value)` pairs in
+//!   [`channel`].
+//! * Anything new belongs here and must be reachable from a seed — a colour written at a call
+//!   site is the next magic number.
+
+use nih_plug_egui::egui::Color32;
+
+// ===========================================================================
+// TIER 1 — SEEDS. This is the part to edit.
+// ===========================================================================
+
+// --- Channel identity ------------------------------------------------------
+// Hues in degrees: 0 = red, 120 = green, 240 = blue. Only the hue is chosen here; saturation and
+// brightness are decided per role by `channel()`, so a channel reads as the same colour whether
+// it is a 12%-brightness background wash or a full-strength drag handle.
+//
+// Keep neighbours far enough apart to survive being dimmed — most chrome lives at low
+// saturation, where close hues merge. Roughly 60–90 degrees apart works; below ~40 does not.
+pub const HUE_LOW: f32 = 233.0; // blue
+pub const HUE_MID: f32 = 20.0; // orange
+pub const HUE_HIGH: f32 = 155.0; // blueish green
+pub const HUE_ALL: f32 = 280.0; // violet — the aggregate, distinct from its three inputs
+
+// --- Functional colours ----------------------------------------------------
+// Outside the hue system on purpose: these mean the same thing in every channel, so they must
+// NOT be derived from a channel hue. Red is always "you have hit a limit".
+
+/// Meter bar with comfortable headroom.
+pub const LEVEL_OK: Color32 = Color32::from_rgb(90, 200, 110);
+/// Meter bar approaching full scale.
+pub const LEVEL_WARN: Color32 = Color32::from_rgb(230, 200, 70);
+/// Meter bar at or near full scale.
+pub const LEVEL_HOT: Color32 = Color32::from_rgb(235, 70, 60);
+
+/// Latched over/ceiling lamp, lit.
+pub const LAMP_ON: Color32 = Color32::from_rgb(255, 40, 40);
+/// The same lamp unlit — dark red rather than grey, so it reads as "off", not "absent".
+pub const LAMP_OFF: Color32 = Color32::from_rgb(40, 12, 12);
+/// Ceiling-hit tick marks along the top edge of the scope.
+pub const CLIP: Color32 = Color32::from_rgb(235, 45, 45);
+
+// Scope traces. The scope is tabbed — one channel at a time — so these never compete with a
+// channel hue: the tab chrome says which channel, these three say what each line is.
+pub const SIGNAL_IN: Color32 = Color32::from_rgb(90, 170, 235);
+pub const SIGNAL_OUT: Color32 = Color32::from_rgb(90, 200, 110);
+pub const SIGNAL_GR: Color32 = Color32::from_rgb(240, 150, 60);
+
+/// The transfer curve in the gain-curve display, and its translucent fill.
+pub const CURVE: Color32 = Color32::from_rgb(120, 200, 160);
+/// The live operating-point dot riding that curve — near-white, so it reads on top of the fill.
+pub const OPERATING_POINT: Color32 = Color32::from_rgb(235, 240, 235);
+/// Threshold marker on the gain curve. Dim on purpose: a reference line, not data.
+pub const THRESHOLD_LINE: Color32 = Color32::from_rgb(80, 60, 45);
+
+// --- Neutrals --------------------------------------------------------------
+// Eight ad-hoc greys collapsed to six named steps. If you need another, add it here rather than
+// reaching for `from_gray` at a call site.
+
+/// Data panels — the scope and the gain curve.
+pub const SURFACE: Color32 = Color32::from_rgb(16, 16, 20);
+/// The meter panel, one step lighter so the cluster reads as its own surface. These were two
+/// different blacks by accident before; they are two on purpose now. Set this equal to
+/// [`SURFACE`] if you would rather they sat flush.
+pub const SURFACE_RAISED: Color32 = Color32::from_rgb(20, 20, 24);
+/// The empty part of a meter bar.
+pub const TRACK: Color32 = Color32::from_rgb(34, 34, 40);
+
+/// Structural lines — the unity diagonal, panel edges.
+pub const GRID: Color32 = Color32::from_gray(45);
+/// Reference lines that should recede — dB gridlines, −6 dB marks.
+pub const GRID_FAINT: Color32 = Color32::from_gray(38);
+
+/// Axis numbers and other text that must not compete with the data.
+pub const TEXT_DIM: Color32 = Color32::from_gray(90);
+/// Body text — band names on the crossover strip.
+pub const TEXT: Color32 = Color32::from_gray(160);
+/// Emphasised text — channel labels, readouts.
+pub const TEXT_BRIGHT: Color32 = Color32::from_gray(210);
+/// Hover and drag feedback, where the point is to be unmistakable.
+pub const TEXT_HOVER: Color32 = Color32::WHITE;
+
+// ===========================================================================
+// TIER 2 — DERIVED. Generated from the seeds above; do not hand-edit.
+// ===========================================================================
+
+/// One channel's colours, all derived from a single hue.
+pub struct Channel {
+    /// Background wash behind a channel's cell. Very dark — it must associate the bars drawn on
+    /// top of it with a channel without competing with them.
+    pub chrome: Color32,
+    /// Band strip on the crossover widget: between [`Channel::chrome`] and [`Channel::edge`].
+    pub strip: Color32,
+    /// Accent rule under a meter cell, and the scope's tab underline. Bright enough to identify
+    /// at a glance.
+    pub edge: Color32,
+    /// Full strength — drag handles and anything else the user grabs.
+    pub handle: Color32,
+}
+
+/// Build a channel's palette from its hue.
+///
+/// The `(saturation, value)` pairs below decide how loudly channel identity reads. Raise
+/// `CHROME`'s value and the cell washes get more obvious; lower it and they recede into the
+/// panel background. `CHROME` is deliberately near the floor: it sits *behind* meter bars.
+pub const fn channel(hue: f32) -> Channel {
+    const CHROME: (f32, f32) = (0.45, 0.115);
+    const STRIP: (f32, f32) = (0.42, 0.20);
+    const EDGE: (f32, f32) = (0.60, 0.55);
+    const HANDLE: (f32, f32) = (0.55, 0.90);
+    Channel {
+        chrome: hsv(hue, CHROME.0, CHROME.1),
+        strip: hsv(hue, STRIP.0, STRIP.1),
+        edge: hsv(hue, EDGE.0, EDGE.1),
+        handle: hsv(hue, HANDLE.0, HANDLE.1),
+    }
+}
+
+/// Indexed by the `LOW`/`MID`/`HIGH`/`ALL` consts in `lib.rs`, so `CHANNELS[i]` lines up with
+/// `meters.level_l[i]` and friends without a lookup step.
+pub const CHANNELS: [Channel; 4] = [
+    channel(HUE_LOW),
+    channel(HUE_MID),
+    channel(HUE_HIGH),
+    channel(HUE_ALL),
+];
+
+/// HSV to RGB, `const` so [`CHANNELS`] is built at compile time.
+///
+/// `h` in degrees (wrapped), `s` and `v` in `0..=1`. The standard sextant algorithm, written out
+/// here only because `ecolor::Hsva`'s conversion is not a `const fn`.
+pub const fn hsv(h: f32, s: f32, v: f32) -> Color32 {
+    // Wrap into 0..360. A loop rather than `%` because float remainder is not available in a
+    // const context on this toolchain; hues are small numbers, so this costs nothing.
+    let mut h = h;
+    while h < 0.0 {
+        h += 360.0;
+    }
+    while h >= 360.0 {
+        h -= 360.0;
+    }
+    let sector = h / 60.0;
+    let i = sector as i32;
+    let f = sector - i as f32;
+    let p = v * (1.0 - s);
+    let q = v * (1.0 - s * f);
+    let t = v * (1.0 - s * (1.0 - f));
+    let (r, g, b) = match i {
+        0 => (v, t, p),
+        1 => (q, v, p),
+        2 => (p, v, t),
+        3 => (p, q, v),
+        4 => (t, p, v),
+        _ => (v, p, q),
+    };
+    Color32::from_rgb(to_u8(r), to_u8(g), to_u8(b))
+}
+
+/// Clamping float-to-byte, `const` for the same reason as [`hsv`].
+const fn to_u8(x: f32) -> u8 {
+    let v = x * 255.0 + 0.5;
+    if v <= 0.0 {
+        0
+    } else if v >= 255.0 {
+        255
+    } else {
+        v as u8
+    }
+}
+
+/// Meter bar colour for an output level in dB.
+///
+/// Functional, not per-channel: −6 dB means the same thing in every band. Thresholds and colours
+/// are both literal so either can be tuned by eye.
+pub fn level_color(db: f32) -> Color32 {
+    if db >= -1.0 {
+        LEVEL_HOT
+    } else if db >= -6.0 {
+        LEVEL_WARN
+    } else {
+        LEVEL_OK
+    }
+}
+
+/// The same colour at `a`/255 opacity, for translucent fills under a trace.
+///
+/// Not `const`: `Color32::from_rgba_unmultiplied` is not a `const fn`, and the premultiplied
+/// constructor that is would push the multiply out to every call site.
+pub fn with_alpha(c: Color32, a: u8) -> Color32 {
+    Color32::from_rgba_unmultiplied(c.r(), c.g(), c.b(), a)
+}
+
+/// Apply the palette to egui's own widgets, so `ParamSlider`, labels and separators sit in the
+/// same world as the hand-painted ones instead of on stock egui defaults.
+///
+/// Call once when the editor is created. Widget colours are per interaction state: `weak_bg_fill`
+/// is an unfilled slider track, `bg_fill` the filled portion. Interactive states borrow the ALL
+/// channel's hue, since egui widgets are not per-band — change that to a dedicated accent seed if
+/// you would rather they were neutral.
+pub fn apply_visuals(ctx: &nih_plug_egui::egui::Context) {
+    use nih_plug_egui::egui::{Stroke, Visuals};
+
+    let accent = &CHANNELS[3];
+    let mut v = Visuals::dark();
+
+    v.panel_fill = SURFACE;
+    v.window_fill = SURFACE;
+    v.extreme_bg_color = SURFACE;
+    v.faint_bg_color = SURFACE_RAISED;
+
+    let w = &mut v.widgets;
+    w.noninteractive.bg_fill = SURFACE_RAISED;
+    w.noninteractive.weak_bg_fill = SURFACE_RAISED;
+    w.noninteractive.bg_stroke = Stroke::new(1.0_f32, GRID_FAINT);
+    w.noninteractive.fg_stroke = Stroke::new(1.0_f32, TEXT);
+
+    w.inactive.bg_fill = TRACK;
+    w.inactive.weak_bg_fill = TRACK;
+    w.inactive.bg_stroke = Stroke::new(1.0_f32, GRID);
+    w.inactive.fg_stroke = Stroke::new(1.0_f32, TEXT_BRIGHT);
+
+    w.hovered.bg_fill = accent.edge;
+    w.hovered.weak_bg_fill = accent.strip;
+    w.hovered.bg_stroke = Stroke::new(1.0_f32, accent.edge);
+    w.hovered.fg_stroke = Stroke::new(1.0_f32, TEXT_HOVER);
+
+    w.active.bg_fill = accent.handle;
+    w.active.weak_bg_fill = accent.edge;
+    w.active.bg_stroke = Stroke::new(1.0_f32, accent.handle);
+    w.active.fg_stroke = Stroke::new(1.0_f32, TEXT_HOVER);
+
+    ctx.set_visuals(v);
+}

src/editor/plot.rs

@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-3.0-or-later
 //! Rolling input/output/gain-reduction plot with per-channel tabs and a flow-speed selector.
 //!
 //! Histories for all four channels run continuously (cheap), so switching tabs shows that
@@ -11,15 +12,16 @@ use nih_plug_egui::egui::{self, pos2, vec2, Align2, Color32, CornerRadius, FontI
 
 use super::METER_FLOOR_DB;
 use crate::meters::{Meters, BUCKET_HZ, NUM_CHANNELS};
+use super::palette;
 
 /// Height of the plot panel.
 const PLOT_PANEL_H: f32 = 150.0;
 /// Number of columns held in the history ring.
 const PLOT_N: usize = 256;
 
-const COLOR_IN: Color32 = Color32::from_rgb(90, 170, 235);
-const COLOR_OUT: Color32 = Color32::from_rgb(90, 200, 110);
-const COLOR_GR: Color32 = Color32::from_rgb(240, 150, 60);
+const COLOR_IN: Color32 = palette::SIGNAL_IN;
+const COLOR_OUT: Color32 = palette::SIGNAL_OUT;
+const COLOR_GR: Color32 = palette::SIGNAL_GR;
 
 /// Rolling history for all channels: a per-channel ring of (in_db, out_db, gr_db) columns.
 struct PlotHistory {
@@ -155,7 +157,7 @@ pub(super) fn draw(ui: &mut egui::Ui, meters: &Meters, state: &mut PlotState) {
     let (rect, _) =
         ui.allocate_exact_size(vec2(ui.available_width(), PLOT_PANEL_H), Sense::hover());
     let p = ui.painter_at(rect);
-    p.rect_filled(rect, CornerRadius::ZERO, Color32::from_rgb(16, 16, 20));
+    p.rect_filled(rect, CornerRadius::ZERO, palette::SURFACE);
 
     let (top, bottom, left, right) =
         (rect.top() + 4.0, rect.bottom() - 4.0, rect.left() + 4.0, rect.right() - 4.0);
@@ -168,13 +170,13 @@ pub(super) fn draw(ui: &mut egui::Ui, meters: &Meters, state: &mut PlotState) {
     // Gridlines (dB).
     for &g in &[0.0f32, -12.0, -24.0, -48.0] {
         let y = y_for_db(g);
-        p.line_segment([pos2(left, y), pos2(right, y)], Stroke::new(1.0, Color32::from_gray(40)));
+        p.line_segment([pos2(left, y), pos2(right, y)], Stroke::new(1.0_f32, palette::GRID_FAINT));
         p.text(
             pos2(left + 2.0, y),
             Align2::LEFT_BOTTOM,
             format!("{g:.0}"),
             FontId::proportional(9.0),
-            Color32::from_gray(90),
+            palette::TEXT_DIM,
         );
     }
 
@@ -192,7 +194,7 @@ pub(super) fn draw(ui: &mut egui::Ui, meters: &Meters, state: &mut PlotState) {
                 // Fill as a strip of per-segment convex quads down to the baseline. A single
                 // concave polygon mis-tessellates in egui (it fans from one corner, leaving stray
                 // triangles), so build convex pieces — one box per time unit — instead.
-                let fill_col = Color32::from_rgba_unmultiplied(color.r(), color.g(), color.b(), 40);
+                let fill_col = palette::with_alpha(color, 40);
                 for seg in pts.windows(2) {
                     let (a, b) = (seg[0], seg[1]);
                     p.add(egui::Shape::convex_polygon(
@@ -202,7 +204,7 @@ pub(super) fn draw(ui: &mut egui::Ui, meters: &Meters, state: &mut PlotState) {
                     ));
                 }
             }
-            p.add(egui::Shape::line(pts, Stroke::new(1.5, color)));
+            p.add(egui::Shape::line(pts, Stroke::new(1.5_f32, color)));
         };
         draw_series(&state.history.in_db[c], &|db| db, COLOR_IN, true);
         draw_series(&state.history.out_db[c], &|db| db, COLOR_OUT, true);
@@ -213,7 +215,7 @@ pub(super) fn draw(ui: &mut egui::Ui, meters: &Meters, state: &mut PlotState) {
         // hit the ceiling (global — shown on every channel's view). One column wide, so runs of
         // hits merge into a continuous segment and a lone hit is just a dot. Nothing otherwise.
         let dx = width / (PLOT_N - 1) as f32;
-        let marker = Color32::from_rgb(235, 45, 45);
+        let marker = palette::CLIP;
         for k in 0..len {
             let idx = (write + PLOT_N - len + k) % PLOT_N;
             if state.history.hit[idx] {

src/lib.rs

@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-3.0-or-later
 use nih_plug::prelude::*;
 use std::sync::Arc;
 
@@ -10,7 +11,7 @@ use dsp::compressor::{Compressor, MAX_LOOKAHEAD_MS};
 use dsp::crossover::Crossover;
 use dsp::limiter::Limiter;
 use meters::Meters;
-use params::{build_settings, Codename206Params};
+use params::{build_settings, Bari206Params};
 
 /// Peak-meter fall: after this long of silence the bars decay by 12 dB. (Matches nih-plug's
 /// gain-gui example feel.)
@@ -22,13 +23,28 @@ const MID: usize = 1;
 const HIGH: usize = 2;
 const ALL: usize = 3;
 
-/// Codename 206 — Stage 3: 3-band crossover + per-band compressors summed into an 'All' channel.
+/// RMS detector time constants, one per channel, indexed by the consts above.
+///
+/// Squaring the detector signal puts a component at twice the fundamental, so a one-pole that
+/// does not span a cycle leaves the detector rippling and the gain intermodulating with the
+/// bass. Measured peak-to-peak detector ripple at a 5 ms window was 4.4 dB at 30 Hz and 2.7 dB
+/// at 50 Hz - squarely in the low band, whose crossover reaches down to 30 Hz. The cost of a
+/// longer window is response time (95% of a step: ~12 ms at 5 ms, ~117 ms at 50 ms), so each
+/// band gets only as much as its frequency range actually needs:
+///
+/// * LOW  - 50 ms: 30 Hz ripple drops to 0.46 dB, and slow is the wanted behaviour down here.
+/// * MID  - 20 ms: enough for body without dulling the band that carries most transients.
+/// * HIGH - 10 ms: nothing up here ripples, so keep it responsive.
+/// * ALL  - 35 ms: full-band, so it must cover the low content too.
+const RMS_WINDOW_MS: [f32; 4] = [50.0, 20.0, 10.0, 35.0];
+
+/// Bari 206 — Stage 3: 3-band crossover + per-band compressors summed into an 'All' channel.
 ///
 /// Signal: input → LR4 crossover → {low, mid, high} each through their own compressor → sum →
 /// 'All' compressor → output. Bypassing low+mid+high collapses it to a plain full-band comp
 /// driven by the 'All' channel (the crossover sums flat).
-struct Codename206 {
-    params: Arc<Codename206Params>,
+struct Bari206 {
+    params: Arc<Bari206Params>,
     sample_rate: f32,
     crossover: Crossover,
     /// Compressors indexed by [`LOW`], [`MID`], [`HIGH`], [`ALL`].
@@ -56,10 +72,10 @@ struct Codename206 {
 /// Limiter gain reduction (dB) above which a plot bucket is flagged as hitting the ceiling.
 const CEILING_HIT_GR_DB: f32 = 0.1;
 
-impl Default for Codename206 {
+impl Default for Bari206 {
     fn default() -> Self {
         Self {
-            params: Arc::new(Codename206Params::default()),
+            params: Arc::new(Bari206Params::default()),
             sample_rate: 48_000.0,
             crossover: Crossover::new(),
             comps: [Compressor::new(), Compressor::new(), Compressor::new(), Compressor::new()],
@@ -76,14 +92,14 @@ impl Default for Codename206 {
     }
 }
 
-impl Codename206 {
+impl Bari206 {
     fn lookahead_samples(&self) -> usize {
         (self.params.look_ahead_ms.value() * 0.001 * self.sample_rate).round() as usize
     }
 }
 
-impl Plugin for Codename206 {
-    const NAME: &'static str = "206 prototype";
+impl Plugin for Bari206 {
+    const NAME: &'static str = "Bari 206";
     const VENDOR: &'static str = "Novoyuuparosk";
     const URL: &'static str = env!("CARGO_PKG_HOMEPAGE");
     const EMAIL: &'static str = "mikkeli@novoyuuparosk.org";
@@ -139,8 +155,8 @@ impl Plugin for Codename206 {
         self.scope_bucket_len =
             ((self.sample_rate / meters::BUCKET_HZ as f32).round() as usize).max(1);
 
-        for comp in &mut self.comps {
-            comp.prepare(self.sample_rate, channels, MAX_LOOKAHEAD_MS);
+        for (i, comp) in self.comps.iter_mut().enumerate() {
+            comp.prepare(self.sample_rate, channels, MAX_LOOKAHEAD_MS, RMS_WINDOW_MS[i]);
         }
         self.crossover.prepare(channels);
         self.crossover.update(
@@ -211,9 +227,47 @@ impl Plugin for Codename206 {
         let num_samples = buffer.samples();
         let mut lvl_l = [0.0f32; meters::NUM_CHANNELS];
         let mut lvl_r = [0.0f32; meters::NUM_CHANNELS];
+        let mut inp = [0.0f32; meters::NUM_CHANNELS]; // mono input level (detector / gain-curve x)
         let mut gr = [0.0f32; meters::NUM_CHANNELS];
         let mut lim_gr = 0.0f32;
 
+        // Params only change on block boundaries here (we do not split blocks on events), so a
+        // smoother that is idle now stays idle for this whole block. When every smoother feeding
+        // a channel is idle - the overwhelming common case, i.e. nobody is touching a knob -
+        // its per-sample values are constants, so lift them out of the sample loop entirely.
+        // That removes 5 Smoother::next() calls and a db_to_gain per channel per sample.
+        let chan_static = |p: &params::CompressorParams| {
+            !p.pre_gain_db.smoothed.is_smoothing()
+                && !p.makeup_db.smoothed.is_smoothing()
+                && !p.mix.smoothed.is_smoothing()
+                && !p.low_slope.smoothed.is_smoothing()
+                && !p.low_curve.smoothed.is_smoothing()
+        };
+        let band_static = [
+            chan_static(&self.params.low),
+            chan_static(&self.params.mid),
+            chan_static(&self.params.high),
+        ];
+        let all_static = chan_static(&self.params.all);
+        let mut band_pre = [1.0f32; 3];
+        for b in 0..3 {
+            if band_static[b] {
+                band_pre[b] = util::db_to_gain_fast(band_params[b].pre_gain_db.smoothed.next());
+                band_set[b].makeup_db = band_params[b].makeup_db.smoothed.next();
+                band_set[b].mix = band_params[b].mix.smoothed.next();
+                band_set[b].low_slope = band_params[b].low_slope.smoothed.next();
+                band_set[b].low_curve = band_params[b].low_curve.smoothed.next();
+            }
+        }
+        let mut all_pre_static = 1.0f32;
+        if all_static {
+            all_pre_static = util::db_to_gain_fast(self.params.all.pre_gain_db.smoothed.next());
+            all_set.makeup_db = self.params.all.makeup_db.smoothed.next();
+            all_set.mix = self.params.all.mix.smoothed.next();
+            all_set.low_slope = self.params.all.low_slope.smoothed.next();
+            all_set.low_curve = self.params.all.low_curve.smoothed.next();
+        }
+
         let mut in_frame = [0.0f32; 2];
         let mut band_in = [[0.0f32; 2]; 3];
         let mut band_out = [[0.0f32; 2]; 3];
@@ -239,14 +293,20 @@ impl Plugin for Codename206 {
             // Drive + compress each band (per-sample smoothed pre-gain & makeup), then sum.
             summed[..n].fill(0.0);
             for b in 0..3 {
-                let pre = util::db_to_gain(band_params[b].pre_gain_db.smoothed.next());
-                for ch in 0..n {
-                    band_in[b][ch] *= pre;
-                }
+                // `_fast` skips the below-(-100dB) branch, which pre_gain_db's -24..+36 range
+                // never reaches, in exchange for a cheaper exp() instead of a general powf().
+                let pre = if band_static[b] {
+                    band_pre[b]
+                } else {
                     band_set[b].makeup_db = band_params[b].makeup_db.smoothed.next();
                     band_set[b].mix = band_params[b].mix.smoothed.next();
                     band_set[b].low_slope = band_params[b].low_slope.smoothed.next();
                     band_set[b].low_curve = band_params[b].low_curve.smoothed.next();
+                    util::db_to_gain_fast(band_params[b].pre_gain_db.smoothed.next())
+                };
+                for ch in 0..n {
+                    band_in[b][ch] *= pre;
+                }
                 self.comps[b].process(&band_in[b][..n], &mut band_out[b][..n], &band_set[b]);
                 for ch in 0..n {
                     summed[ch] += band_out[b][ch];
@@ -257,6 +317,7 @@ impl Plugin for Codename206 {
                     let out_r = band_out[b][r].abs();
                     // Wet gain reduction (what the comp computes), independent of the mix.
                     let g = self.comps[b].gain_reduction_db();
+                    inp[b] = inp[b].max(in_mono);
                     lvl_l[b] = lvl_l[b].max(out_l);
                     lvl_r[b] = lvl_r[b].max(out_r);
                     gr[b] = gr[b].max(g);
@@ -269,14 +330,18 @@ impl Plugin for Codename206 {
             }
 
             // 'All' aggregate channel over the summed bands (driven before its compressor).
-            let all_pre = util::db_to_gain(self.params.all.pre_gain_db.smoothed.next());
-            for ch in 0..n {
-                summed[ch] *= all_pre;
-            }
+            let all_pre = if all_static {
+                all_pre_static
+            } else {
                 all_set.makeup_db = self.params.all.makeup_db.smoothed.next();
                 all_set.mix = self.params.all.mix.smoothed.next();
                 all_set.low_slope = self.params.all.low_slope.smoothed.next();
                 all_set.low_curve = self.params.all.low_curve.smoothed.next();
+                util::db_to_gain_fast(self.params.all.pre_gain_db.smoothed.next())
+            };
+            for ch in 0..n {
+                summed[ch] *= all_pre;
+            }
             self.comps[ALL].process(&summed[..n], &mut out_frame[..n], &all_set);
 
             // Output brickwall limiter.
@@ -287,6 +352,7 @@ impl Plugin for Codename206 {
                 let out_l = out_frame[0].abs();
                 let out_r = out_frame[r].abs();
                 let g = self.comps[ALL].gain_reduction_db();
+                inp[ALL] = inp[ALL].max(in_mono);
                 lvl_l[ALL] = lvl_l[ALL].max(out_l);
                 lvl_r[ALL] = lvl_r[ALL].max(out_r);
                 gr[ALL] = gr[ALL].max(g);
@@ -327,6 +393,7 @@ impl Plugin for Codename206 {
             for i in 0..meters::NUM_CHANNELS {
                 meters::decay_store(&self.meters.level_l[i], lvl_l[i], w);
                 meters::decay_store(&self.meters.level_r[i], lvl_r[i], w);
+                meters::decay_store(&self.meters.input_level[i], inp[i], w);
                 meters::decay_store(&self.meters.gain_reduction_db[i], gr[i], w);
             }
             meters::decay_store(&self.meters.limiter_gr_db, lim_gr, w);
@@ -336,8 +403,8 @@ impl Plugin for Codename206 {
     }
 }
 
-impl ClapPlugin for Codename206 {
-    const CLAP_ID: &'static str = "com.mikkeli.codename-206";
+impl ClapPlugin for Bari206 {
+    const CLAP_ID: &'static str = "org.novoyuuparosk.bari-206";
     const CLAP_DESCRIPTION: Option<&'static str> =
         Some("Multiband compressor/limiter (stage 3: 3-band + 'All' channel)");
     const CLAP_MANUAL_URL: Option<&'static str> = Some(Self::URL);
@@ -351,11 +418,11 @@ impl ClapPlugin for Codename206 {
     ];
 }
 
-impl Vst3Plugin for Codename206 {
-    const VST3_CLASS_ID: [u8; 16] = *b"Codename206Maxi!";
+impl Vst3Plugin for Bari206 {
+    const VST3_CLASS_ID: [u8; 16] = *b"Bari206Multiband";
     const VST3_SUBCATEGORIES: &'static [Vst3SubCategory] =
         &[Vst3SubCategory::Fx, Vst3SubCategory::Dynamics];
 }
 
-nih_export_clap!(Codename206);
-nih_export_vst3!(Codename206);
+nih_export_clap!(Bari206);
+nih_export_vst3!(Bari206);

src/meters.rs

@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-3.0-or-later
 //! Lock-free meter state shared from the audio thread to the editor.
 //!
 //! Two feeds, both written by `process()` (single producer) and read by the editor (single
@@ -26,6 +27,9 @@ pub struct Meters {
     pub level_l: [AtomicF32; NUM_CHANNELS],
     /// Right output level per channel (== left for mono signals).
     pub level_r: [AtomicF32; NUM_CHANNELS],
+    /// Mono **input** level per channel (post pre-gain = what the compressor detects). Drives the
+    /// gain-curve operating-point fill. Peak-with-decay.
+    pub input_level: [AtomicF32; NUM_CHANNELS],
     /// Compressor gain reduction per channel in **dB (>= 0)**. Mono by design — detection is
     /// stereo-linked, so the same gain applies to both channels.
     pub gain_reduction_db: [AtomicF32; NUM_CHANNELS],
@@ -40,6 +44,7 @@ impl Default for Meters {
         Self {
             level_l: std::array::from_fn(|_| AtomicF32::new(0.0)),
             level_r: std::array::from_fn(|_| AtomicF32::new(0.0)),
+            input_level: std::array::from_fn(|_| AtomicF32::new(0.0)),
             gain_reduction_db: std::array::from_fn(|_| AtomicF32::new(0.0)),
             limiter_gr_db: AtomicF32::new(0.0),
             scope: ScopeRing::default(),
@@ -55,6 +60,7 @@ impl Meters {
         for i in 0..NUM_CHANNELS {
             self.level_l[i].store(0.0, Ordering::Relaxed);
             self.level_r[i].store(0.0, Ordering::Relaxed);
+            self.input_level[i].store(0.0, Ordering::Relaxed);
             self.gain_reduction_db[i].store(0.0, Ordering::Relaxed);
         }
         self.limiter_gr_db.store(0.0, Ordering::Relaxed);

src/params.rs

@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-3.0-or-later
 //! Plugin parameters and their layout.
 //!
 //! Holds the global controls plus four `CompressorParams` blocks (low/mid/high + the 'All'
@@ -22,7 +23,7 @@ pub enum DetectionMode {
 }
 
 #[derive(Params)]
-pub struct Codename206Params {
+pub struct Bari206Params {
     #[persist = "editor-state"]
     pub editor_state: Arc<EguiState>,
 
@@ -71,7 +72,8 @@ pub struct CompressorParams {
     /// Low shaper slope at the silence floor (1 = unity; >1 fans up/boost, <1 fans down/cut).
     #[id = "lowslope"]
     pub low_slope: FloatParam,
-    /// Low shaper curvature (0 = straight line, 1 = max bend toward a bounded saturation).
+    /// Low shaper curvature (−1..1): bipolar mid-bulge, 0 = straight. +bulges up (boost quiet
+    /// middle), − bulges down (suppress). Endpoints (silence + knee) stay fixed.
     #[id = "lowcurve"]
     pub low_curve: FloatParam,
     #[id = "attack"]
@@ -85,7 +87,7 @@ pub struct CompressorParams {
     pub mix: FloatParam,
 }
 
-impl Default for Codename206Params {
+impl Default for Bari206Params {
     fn default() -> Self {
         Self {
             editor_state: EguiState::from_size(760, 520),
@@ -182,7 +184,7 @@ impl Default for CompressorParams {
             .with_smoother(SmoothingStyle::Linear(20.0))
             .with_value_to_string(formatters::v2s_f32_rounded(2)),
 
-            low_curve: FloatParam::new("Low Curve", 0.0, FloatRange::Linear { min: 0.0, max: 1.0 })
+            low_curve: FloatParam::new("Low Curve", 0.0, FloatRange::Linear { min: -1.0, max: 1.0 })
                 .with_smoother(SmoothingStyle::Linear(20.0))
                 .with_value_to_string(formatters::v2s_f32_percentage(0))
                 .with_string_to_value(formatters::s2v_f32_percentage()),

tools/brand-plugin.sh

@@ -0,0 +1,355 @@
+#!/bin/sh
+# SPDX-License-Identifier: GPL-3.0-or-later
+# brand-plugin.sh - rename this plugin, everywhere, in one go.
+#
+# check-branding.sh tells you what disagrees. This changes it. They share
+# branding.conf: this script rewrites that file and every copy of the old values
+# in tracked files, then runs the checker and reports what it says. A run that
+# ends with the checker green is a rename that landed.
+#
+# Dry run by default:
+#   sh brand-plugin.sh --display "Bari 206"
+#   sh brand-plugin.sh --display "Bari 206" --vendor Novoyuuparosk --apply
+#
+# Options:
+#   --display NAME    the product name, with spaces and capitals. Everything
+#                     else that can be derived, is derived from this.
+#   --pkg NAME        override the derived Cargo package name.
+#   --vendor NAME     --email ADDR    --homepage URL
+#   --description D   --clap-description D
+#   --struct NAME     override the derived Rust type name.
+#   --allow-identity-change   permit CLAP_ID / VST3_CLASS_ID to move. See below.
+#   --apply           actually write. Without it, nothing is modified.
+
+set -u
+# Resolve the repo root: these live in tools/, every path they touch is
+# repo-relative, and they must behave the same wherever they are invoked from.
+cd "$(dirname "$0")/.." || exit 1
+[ -f tools/branding.conf ] || { printf 'tools/branding.conf not found\n' >&2; exit 1; }
+# shellcheck disable=SC1091
+. ./tools/branding.conf
+
+OLD_PKG="$PKG"; OLD_DISPLAY="$DISPLAY"; OLD_PLUGIN_NAME="$PLUGIN_NAME"
+OLD_VENDOR="$VENDOR"; OLD_EMAIL="$EMAIL"; OLD_HOMEPAGE="$HOMEPAGE"; OLD_AUTHOR="$AUTHOR"
+OLD_DESCRIPTION="$DESCRIPTION"; OLD_CLAP_DESCRIPTION="$CLAP_DESCRIPTION"
+OLD_CLAP_ID="$CLAP_ID"; OLD_VST3="$VST3_CLASS_ID"
+OLD_STRUCT="$STRUCT"; OLD_PARAMS_STRUCT="$PARAMS_STRUCT"
+
+new_display=""; new_pkg=""; new_vendor=""; new_email=""; new_homepage=""
+new_description=""; new_clap_description=""; new_struct=""; new_author=""
+new_clap_id=""; new_vst3=""; apply=0; allow_identity=0
+
+while [ $# -gt 0 ]; do
+  case "$1" in
+    --display)           new_display="${2:?}"; shift 2 ;;
+    --pkg)               new_pkg="${2:?}"; shift 2 ;;
+    --vendor)            new_vendor="${2:?}"; shift 2 ;;
+    --author)            new_author="${2:?}"; shift 2 ;;
+    --email)             new_email="${2:?}"; shift 2 ;;
+    --homepage)          new_homepage="${2:?}"; shift 2 ;;
+    --description)       new_description="${2:?}"; shift 2 ;;
+    --clap-description)  new_clap_description="${2:?}"; shift 2 ;;
+    --struct)            new_struct="${2:?}"; shift 2 ;;
+    --clap-id)           new_clap_id="${2:?}"; shift 2 ;;
+    --vst3-class-id)     new_vst3="${2:?}"; shift 2 ;;
+    --allow-identity-change) allow_identity=1; shift ;;
+    --apply)             apply=1; shift ;;
+    -h|--help)           sed -n '3,25p' "$0"; exit 0 ;;
+    *) printf 'unknown option: %s\n' "$1" >&2; exit 2 ;;
+  esac
+done
+
+# Interactive when nothing was passed and there is a terminal to ask at. Every
+# prompt offers the current value; Enter keeps it, so a run that answers nothing
+# is a no-op rather than a surprise. Optional fields additionally accept "-" to
+# clear them.
+ask() { # ask VARNAME PROMPT CURRENT
+  printf '  %s [%s]: ' "$2" "$3" > /dev/tty
+  IFS= read -r _reply < /dev/tty || _reply=""
+  [ -n "$_reply" ] || _reply="$3"
+  [ "$_reply" = "-" ] && _reply=""
+  eval "$1=\$_reply"
+}
+if [ -z "$new_display" ] && [ -t 0 ] && [ -c /dev/tty ]; then
+  printf 'branding this plugin - Enter keeps the current value, "-" clears an optional one\n\n'
+  ask new_display          "display name    " "$OLD_DISPLAY"
+  ask new_vendor           "vendor (org)    " "$OLD_VENDOR"
+  ask new_author           "cargo author    " "$OLD_AUTHOR"
+  ask new_email            "email           " "$OLD_EMAIL"
+  ask new_homepage         "homepage        " "$OLD_HOMEPAGE"
+  ask new_description      "cargo description" "$OLD_DESCRIPTION"
+  ask new_clap_description "clap description" "$OLD_CLAP_DESCRIPTION"
+  printf '\n'
+fi
+[ -n "$new_display" ] || { printf 'nothing to do: pass --display "New Name" (or run interactively)\n' >&2; exit 2; }
+
+# --- derivation -------------------------------------------------------------
+# Package name: lowercase, every run of non-alphanumerics becomes one separator,
+# ends trimmed. Cargo accepts both hyphens and underscores in a package name and
+# converts to underscores for the built artifact, which nih_plug_xtask already
+# accounts for; underscores are used here to match the Rust convention.
+derive_pkg() {
+  printf '%s' "$1" | tr '[:upper:]' '[:lower:]' \
+    | sed -e 's/[^a-z0-9]\{1,\}/_/g' -e 's/^_//' -e 's/_$//'
+}
+# Rust type name: CamelCase, non-alphanumerics dropped entirely.
+derive_struct() {
+  printf '%s' "$1" | sed -e 's/[^A-Za-z0-9]\{1,\}/ /g' \
+    | awk '{for(i=1;i<=NF;i++) printf "%s%s", toupper(substr($i,1,1)), substr($i,2); print ""}'
+}
+[ -n "$new_pkg" ]    || new_pkg=$(derive_pkg "$new_display")
+[ -n "$new_struct" ] || new_struct=$(derive_struct "$new_display")
+new_params_struct="${new_struct}Params"
+[ -n "$new_vendor" ]      || new_vendor="$OLD_VENDOR"
+[ -n "$new_author" ]      || new_author="$OLD_AUTHOR"
+[ -n "$new_email" ]       || new_email="$OLD_EMAIL"
+[ -n "$new_homepage" ]    || new_homepage="$OLD_HOMEPAGE"
+[ -n "$new_description" ] || new_description="$OLD_DESCRIPTION"
+[ -n "$new_clap_description" ] || new_clap_description="$OLD_CLAP_DESCRIPTION"
+
+# --- validation -------------------------------------------------------------
+fail=0
+die() { printf '  INVALID  %s\n' "$1"; fail=$((fail+1)); }
+
+case "$new_pkg" in
+  "")        die "derived package name is empty" ;;
+  [0-9]*)    die "package name \"$new_pkg\" starts with a digit - cargo rejects this outright" ;;
+esac
+case "$new_pkg" in
+  test|core|std|alloc|proc_macro)
+    die "package name \"$new_pkg\" collides with a built-in crate" ;;
+  as|break|const|continue|crate|dyn|else|enum|extern|false|fn|for|if|impl|in|let|loop|match|mod|move|mut|pub|ref|return|self|static|struct|super|trait|true|type|unsafe|use|where|while|async|await|box|do|final|macro|override|priv|typeof|unsized|virtual|yield|try)
+    die "package name \"$new_pkg\" is a Rust keyword - cargo rejects this" ;;
+esac
+# bundler.toml uses the package name as a TOML bare key.
+case "$new_pkg" in *[!a-zA-Z0-9_-]*) die "package name \"$new_pkg\" is not a valid TOML bare key" ;; esac
+case "$new_struct" in ""|[0-9]*) die "derived type name \"$new_struct\" is not a valid Rust identifier" ;; esac
+
+# --- frozen identity --------------------------------------------------------
+identity_note=""
+if [ -n "$new_clap_id" ] || [ -n "$new_vst3" ]; then
+  if [ "$allow_identity" -eq 0 ]; then
+    die "CLAP_ID / VST3_CLASS_ID are frozen identity; pass --allow-identity-change to move them"
+  fi
+fi
+[ -n "$new_clap_id" ] || new_clap_id="$OLD_CLAP_ID"
+[ -n "$new_vst3" ]    || new_vst3="$OLD_VST3"
+
+# VST3_CLASS_ID is a fixed 16-byte array, so it cannot simply be derived. Propose
+# one from the new name and let a human decide - it is frozen the moment it ships.
+proposed_vst3=$(printf '%s' "${new_struct}Plugin000000000000" | cut -c1-16)
+n=$(printf '%s' "$new_vst3" | wc -c | tr -d ' ')
+[ "$n" -eq 16 ] || die "VST3_CLASS_ID \"$new_vst3\" is $n bytes, must be exactly 16"
+
+case "$new_clap_id" in
+  *\ *|*[A-Z]*) die "CLAP_ID \"$new_clap_id\" must be lowercase with no spaces" ;;
+  *.*) ;;
+  *) die "CLAP_ID \"$new_clap_id\" should be dotted reverse-DNS" ;;
+esac
+
+# CLAP_DESCRIPTION is user-facing: keep development history out of it.
+for hist in "$CODENAME" "$OLD_DISPLAY" "$OLD_PKG"; do
+  case "$new_clap_description" in
+    *"$hist"*) die "CLAP_DESCRIPTION still mentions \"$hist\" - it is shown to users, who never knew the development name" ;;
+  esac
+done
+
+# --- plan -------------------------------------------------------------------
+printf 'rename plan\n\n'
+row() { [ "$2" = "$3" ] && printf '  %-18s %s (unchanged)\n' "$1" "$2" || printf '  %-18s %s  ->  %s\n' "$1" "$2" "$3"; }
+row "package"        "$OLD_PKG"             "$new_pkg"
+row "display"        "$OLD_DISPLAY"         "$new_display"
+row "Plugin::NAME"   "$OLD_PLUGIN_NAME"     "$new_display"
+row "vendor"         "$OLD_VENDOR"          "$new_vendor"
+row "cargo author"   "$OLD_AUTHOR"          "$new_author"
+row "email"          "$OLD_EMAIL"           "$new_email"
+row "homepage"       "$OLD_HOMEPAGE"        "$new_homepage"
+row "description"    "$OLD_DESCRIPTION"     "$new_description"
+row "clap desc"      "$OLD_CLAP_DESCRIPTION" "$new_clap_description"
+row "struct"         "$OLD_STRUCT"          "$new_struct"
+row "params struct"  "$OLD_PARAMS_STRUCT"   "$new_params_struct"
+row "CLAP_ID"        "$OLD_CLAP_ID"         "$new_clap_id"
+row "VST3_CLASS_ID"  "$OLD_VST3"            "$new_vst3"
+printf '\n  repo codename stays %s - fixed at creation, never renamed\n' "$CODENAME"
+if [ "$new_vst3" = "$OLD_VST3" ]; then
+  printf '  suggested VST3_CLASS_ID for this name (16 bytes): "%s"\n' "$proposed_vst3"
+  printf '    apply with --vst3-class-id "%s" --allow-identity-change, and only before first release\n' "$proposed_vst3"
+fi
+
+if [ "$fail" -ne 0 ]; then
+  printf '\n%d problem(s); nothing written.\n' "$fail"
+  exit 1
+fi
+
+if [ "$apply" -eq 0 ]; then
+  printf '\nDry run. Re-run with --apply to write these changes.\n'
+  exit 0
+fi
+
+# --- apply ------------------------------------------------------------------
+# Three scratch files, one trap: the regenerated site table, the rows carried
+# through from the old one, and the value-substitution pairs.
+gen="$(mktemp)"; keep="$(mktemp)"; subst_file="$(mktemp)"
+trap 'rm -f "$gen" "$keep" "$subst_file"' EXIT
+
+T="$(printf '\t')"
+{
+  printf 'req%spkg.cargo%sCargo.toml%sname = "%s"\n'            "$T" "$T" "$T" "$new_pkg"
+  printf 'req%spkg.bundler%sbundler.toml%s[%s]\n'               "$T" "$T" "$T" "$new_pkg"
+  printf 'opt%spkg.lock%sCargo.lock%sname = "%s"\n'             "$T" "$T" "$T" "$new_pkg"
+  printf 'opt%spkg.ci%s.github/workflows/ci.yaml%scargo xtask bundle %s\n' "$T" "$T" "$T" "$new_pkg"
+  printf 'opt%spkg.readme%sREADME.md%scargo xtask bundle %s\n'  "$T" "$T" "$T" "$new_pkg"
+  printf 'req%sdisplay.bundler%sbundler.toml%sname = "%s"\n'    "$T" "$T" "$T" "$new_display"
+  printf 'opt%sdisplay.notice%sNOTICE%s%s\n'                    "$T" "$T" "$T" "$new_display"
+  printf 'req%sname.plugin%s%s%sconst NAME: &'"'"'static str = "%s"\n'        "$T" "$T" "$LIB_FILE" "$T" "$new_display"
+  printf 'req%svendor.plugin%s%s%sconst VENDOR: &'"'"'static str = "%s"\n'    "$T" "$T" "$LIB_FILE" "$T" "$new_vendor"
+  printf 'req%semail.plugin%s%s%sconst EMAIL: &'"'"'static str = "%s"\n'      "$T" "$T" "$LIB_FILE" "$T" "$new_email"
+  printf 'req%sauthors.cargo%sCargo.toml%sauthors = ["%s <%s>"]\n' "$T" "$T" "$T" "$new_author" "$new_email"
+  printf 'req%shomepage.cargo%sCargo.toml%shomepage = "%s"\n'   "$T" "$T" "$T" "$new_homepage"
+  printf 'req%surl.plugin%s%s%sconst URL: &'"'"'static str = env!("CARGO_PKG_HOMEPAGE")\n' "$T" "$T" "$LIB_FILE" "$T"
+  printf 'req%sdescription.cargo%sCargo.toml%sdescription = "%s"\n' "$T" "$T" "$T" "$new_description"
+  # Narrowest distinctive fragment, not the whole statement: rustfmt wraps a long
+  # CLAP_DESCRIPTION onto its own line, and a pattern spanning the assignment
+  # would then never match a correctly formatted file.
+  printf 'req%sdescription.clap%s%s%sSome("%s")\n' "$T" "$T" "$LIB_FILE" "$T" "$new_clap_description"
+  printf 'req%sclapid.plugin%s%s%sconst CLAP_ID: &'"'"'static str = "%s"\n'  "$T" "$T" "$LIB_FILE" "$T" "$new_clap_id"
+  printf 'req%svst3id.plugin%s%s%sconst VST3_CLASS_ID: [u8; 16] = *b"%s"\n'  "$T" "$T" "$LIB_FILE" "$T" "$new_vst3"
+  printf 'req%sstruct.def%s%s%sstruct %s {\n'                   "$T" "$T" "$LIB_FILE" "$T" "$new_struct"
+  printf 'req%sstruct.plugin%s%s%simpl Plugin for %s {\n'       "$T" "$T" "$LIB_FILE" "$T" "$new_struct"
+  printf 'req%sstruct.clap%s%s%simpl ClapPlugin for %s {\n'     "$T" "$T" "$LIB_FILE" "$T" "$new_struct"
+  printf 'req%sstruct.vst3%s%s%simpl Vst3Plugin for %s {\n'     "$T" "$T" "$LIB_FILE" "$T" "$new_struct"
+  printf 'req%sstruct.exportclap%s%s%snih_export_clap!(%s);\n'  "$T" "$T" "$LIB_FILE" "$T" "$new_struct"
+  printf 'req%sstruct.exportvst3%s%s%snih_export_vst3!(%s);\n'  "$T" "$T" "$LIB_FILE" "$T" "$new_struct"
+  printf 'req%sparams.def%s%s%sstruct %s {\n'                   "$T" "$T" "$PARAMS_FILE" "$T" "$new_params_struct"
+  printf 'req%sparams.default%s%s%simpl Default for %s {\n'     "$T" "$T" "$PARAMS_FILE" "$T" "$new_params_struct"
+  printf 'req%sparams.field%s%s%sparams: Arc<%s>,\n'            "$T" "$T" "$LIB_FILE" "$T" "$new_params_struct"
+  printf 'opt%sdeploy.pkg%sdeploy.ps1%s$Package = "%s"\n'       "$T" "$T" "$T" "$new_pkg"
+  printf 'opt%sdeploy.vst3%sdeploy.ps1%s$vst3Name = "%s.vst3"\n' "$T" "$T" "$T" "$new_display"
+  printf 'opt%sdeploy.clap%sdeploy.ps1%s$clapName = "%s.clap"\n' "$T" "$T" "$T" "$new_display"
+} > "$gen"
+
+# Pass 1 - site-directed. Each owned row in the existing table carries the OLD
+# resolved literal for its site; the regenerated row carries the new one. Rewriting
+# by that pair is unambiguous, which plain value substitution is not: AUTHOR
+# defaults to VENDOR, so both fields can hold the same old string and a global
+# replace cannot tell which occurrence belongs to which. This must run BEFORE
+# pass 2, or the global replace consumes the old literals first and leaves the
+# precise rewrite with nothing to match.
+sites="tools/branding-sites.tsv"
+T="$(printf '\t')"
+if [ -f "$sites" ]; then
+  while IFS="$T" read -r ok_ oo_ of_ op_; do
+    case "$ok_" in ''|\#*) continue ;; esac
+    np_=$(awk -F"$T" -v o="$oo_" '$2==o {print $4; exit}' "$gen")
+    [ -n "$np_" ] || continue
+    [ "$np_" != "$op_" ] || continue
+    [ -f "$of_" ] || continue
+    esc_o=$(printf '%s' "$op_" | sed 's/[][\.*^$/|&]/\\&/g')
+    esc_n=$(printf '%s' "$np_" | sed 's/[\\/&|]/\\&/g')
+    tmp_=$(mktemp)
+    sed "s|$esc_o|$esc_n|g" "$of_" > "$tmp_" && cat "$tmp_" > "$of_"
+    rm -f "$tmp_"
+  done < "$sites"
+  printf '  pass 1: rewrote known sites from the table\n'
+fi
+
+# Pass 2 - value substitution, for everything the table does not enumerate:
+# doc comments, use sites in other modules, prose in the README.
+# Longest values first: a shorter spelling can be a substring of a longer one
+# (the package name inside a URL, say), and replacing it first would corrupt the
+# longer match. branding.conf is excluded and rewritten wholesale below, so its
+# STALE list is never rewritten into meaninglessness.
+{
+  printf '%s\t%s\n' "$OLD_CLAP_ID" "$new_clap_id"
+  printf '%s\t%s\n' "$OLD_HOMEPAGE" "$new_homepage"
+  printf '%s\t%s\n' "$OLD_CLAP_DESCRIPTION" "$new_clap_description"
+  printf '%s\t%s\n' "$OLD_DESCRIPTION" "$new_description"
+  printf '%s\t%s\n' "$OLD_PARAMS_STRUCT" "$new_params_struct"
+  printf '%s\t%s\n' "$OLD_VST3" "$new_vst3"
+  printf '%s\t%s\n' "$OLD_PLUGIN_NAME" "$new_display"
+  printf '%s\t%s\n' "$OLD_DISPLAY" "$new_display"
+  printf '%s\t%s\n' "$OLD_STRUCT" "$new_struct"
+  printf '%s\t%s\n' "$OLD_EMAIL" "$new_email"
+  printf '%s\t%s\n' "$OLD_AUTHOR" "$new_author"
+  printf '%s\t%s\n' "$OLD_VENDOR" "$new_vendor"
+  printf '%s\t%s\n' "$OLD_PKG" "$new_pkg"
+} | awk -F'\t' '$1 != $2 { print length($1)"\t"$0 }' | sort -rn | cut -f2- > "$subst_file"
+
+changed=0
+git ls-files 2>/dev/null | while IFS= read -r f; do
+  [ -f "$f" ] || continue
+  # branding.conf alone is excluded: it is rewritten wholesale below, and its
+  # STALE list names every retired spelling by design. The site table IS
+  # substituted, so hand-added custom rows track the rename; owned rows are
+  # regenerated afterwards regardless.
+  case "$f" in tools/branding.conf) continue ;; esac
+  before=$(cat "$f")
+  after="$before"
+  while IFS="$(printf '\t')" read -r old new; do
+    [ -n "$old" ] || continue
+    after=$(printf '%s' "$after" | sed "s|$(printf '%s' "$old" | sed 's/[][\.*^$/|&]/\\&/g')|$(printf '%s' "$new" | sed 's/[\\/&|]/\\&/g')|g")
+  done < "$subst_file"
+  if [ "$before" != "$after" ]; then printf '%s\n' "$after" > "$f"; printf '  rewrote %s\n' "$f"; fi
+done
+
+# branding.conf last, with the retired spellings appended to STALE so the next
+# run of the checker sweeps for anything this pass missed.
+# Deduplicated: two fields can retire to the same spelling - DISPLAY and
+# PLUGIN_NAME are commonly identical - and listing it twice makes the checker
+# report the same drift twice. Note that neither this script nor the checker
+# contains a branding literal anywhere: both read every name from
+# branding.conf, so a rename never has to rewrite its own tooling.
+retired=$(cut -f1 "$subst_file" | awk '!seen[$0]++')
+sed -e "s|^PKG=.*|PKG=\"$new_pkg\"|" \
+    -e "s|^DISPLAY=.*|DISPLAY=\"$new_display\"|" \
+    -e "s|^PLUGIN_NAME=.*|PLUGIN_NAME=\"$new_display\"|" \
+    -e "s|^VENDOR=.*|VENDOR=\"$new_vendor\"|" \
+    -e "s|^# *AUTHOR=.*|AUTHOR=\"$new_author\"|" \
+    -e "s|^AUTHOR=.*|AUTHOR=\"$new_author\"|" \
+    -e "s|^EMAIL=.*|EMAIL=\"$new_email\"|" \
+    -e "s|^HOMEPAGE=.*|HOMEPAGE=\"$new_homepage\"|" \
+    -e "s|^DESCRIPTION=.*|DESCRIPTION=\"$new_description\"|" \
+    -e "s|^CLAP_DESCRIPTION=.*|CLAP_DESCRIPTION=\"$new_clap_description\"|" \
+    -e "s|^CLAP_ID=.*|CLAP_ID=\"$new_clap_id\"|" \
+    -e "s|^VST3_CLASS_ID=.*|VST3_CLASS_ID=\"$new_vst3\"|" \
+    -e "s|^STRUCT=.*|STRUCT=\"$new_struct\"|" \
+    -e "s|^PARAMS_STRUCT=.*|PARAMS_STRUCT=\"$new_params_struct\"|" \
+    tools/branding.conf > tools/branding.conf.new
+if [ -n "$retired" ]; then
+  { sed '$ s/"$//' tools/branding.conf.new; printf '%s"\n' "$retired"; } > tools/branding.conf
+else
+  # Nothing retired (a no-op rename, or a regeneration): leave STALE untouched
+  # rather than appending a blank line to it on every run.
+  cat tools/branding.conf.new > tools/branding.conf
+fi
+rm -f tools/branding.conf.new
+if [ "$new_author" = "$new_vendor" ]; then
+  # Identical to VENDOR, so re-comment it: the conf should keep showing that this
+  # value derives rather than pinning a duplicate that then has to be maintained.
+  tmp_c=$(mktemp)
+  sed "s|^AUTHOR=.*|# AUTHOR=\"$new_author\"|" tools/branding.conf > "$tmp_c" && cat "$tmp_c" > tools/branding.conf
+  rm -f "$tmp_c"
+fi
+printf '  rewrote tools/branding.conf (retired spellings appended to STALE)\n'
+
+# Regenerate the site table. Rows whose owner this script recognises are
+# rewritten with the new resolved literals; every other row - anything marked
+# custom, or added by hand for a file this template does not ship - is carried
+# through untouched. Clobbering those silently is how a tool stops being trusted.
+sites="tools/branding-sites.tsv"
+
+owned=$(cut -f2 "$gen")
+if [ -f "$sites" ]; then
+  grep '^#' "$sites" > "$keep" 2>/dev/null || : > "$keep"
+  while IFS="$T" read -r k o f pat; do
+    case "$k" in ''|\#*) continue ;; esac
+    printf '%s\n' "$owned" | grep -qxF "$o" || printf '%s%s%s%s%s%s%s\n' "$k" "$T" "$o" "$T" "$f" "$T" "$pat" >> "$keep"
+  done < "$sites"
+else
+  : > "$keep"
+fi
+{ cat "$keep"; cat "$gen"; } > "$sites"
+printf '  rewrote %s (%s owned rows, %s preserved)\n' "$sites" "$(wc -l < "$gen" | tr -d ' ')" "$(grep -cv '^#' "$keep" 2>/dev/null || echo 0)"
+
+printf '\nverifying with check-branding.sh\n\n'
+sh tools/check-branding.sh

tools/branding-sites.tsv

@@ -0,0 +1,29 @@
+req	pkg.cargo	Cargo.toml	name = "bari_206"
+req	pkg.bundler	bundler.toml	[bari_206]
+opt	pkg.lock	Cargo.lock	name = "bari_206"
+opt	pkg.ci	.github/workflows/ci.yaml	cargo xtask bundle bari_206
+opt	pkg.readme	README.md	cargo xtask bundle bari_206
+req	display.bundler	bundler.toml	name = "Bari 206"
+opt	display.notice	NOTICE	Bari 206
+req	name.plugin	src/lib.rs	const NAME: &'static str = "Bari 206"
+req	vendor.plugin	src/lib.rs	const VENDOR: &'static str = "Novoyuuparosk"
+req	email.plugin	src/lib.rs	const EMAIL: &'static str = "mikkeli@novoyuuparosk.org"
+req	authors.cargo	Cargo.toml	authors = ["Mikkeli Matlock <mikkeli@novoyuuparosk.org>"]
+req	homepage.cargo	Cargo.toml	homepage = "https://github.com/mikkeli/codename-206"
+req	url.plugin	src/lib.rs	const URL: &'static str = env!("CARGO_PKG_HOMEPAGE")
+req	description.cargo	Cargo.toml	description = "A VST3/CLAP multiband compressor/limiter with a custom gain-curve display"
+req	description.clap	src/lib.rs	Some("Multiband compressor/limiter (stage 3: 3-band + 'All' channel)")
+req	clapid.plugin	src/lib.rs	const CLAP_ID: &'static str = "org.novoyuuparosk.bari-206"
+req	vst3id.plugin	src/lib.rs	const VST3_CLASS_ID: [u8; 16] = *b"Bari206Multiband"
+req	struct.def	src/lib.rs	struct Bari206 {
+req	struct.plugin	src/lib.rs	impl Plugin for Bari206 {
+req	struct.clap	src/lib.rs	impl ClapPlugin for Bari206 {
+req	struct.vst3	src/lib.rs	impl Vst3Plugin for Bari206 {
+req	struct.exportclap	src/lib.rs	nih_export_clap!(Bari206);
+req	struct.exportvst3	src/lib.rs	nih_export_vst3!(Bari206);
+req	params.def	src/params.rs	struct Bari206Params {
+req	params.default	src/params.rs	impl Default for Bari206Params {
+req	params.field	src/lib.rs	params: Arc<Bari206Params>,
+opt	deploy.pkg	deploy.ps1	$Package = "bari_206"
+opt	deploy.vst3	deploy.ps1	$vst3Name = "Bari 206.vst3"
+opt	deploy.clap	deploy.ps1	$clapName = "Bari 206.clap"

tools/branding.conf

@@ -0,0 +1,66 @@
+# SPDX-License-Identifier: GPL-3.0-or-later
+# branding.conf - this plugin's canonical identity.
+#
+# Managed by tools/brand-plugin.sh, read by tools/check-branding.sh. Hand-editing
+# works and is sometimes the quickest thing, but the helper is what keeps this
+# file, the source tree and tools/branding-sites.tsv agreeing with each other.
+# Edit here and you are on the hook for running the checker afterwards.
+
+# --- derivations ------------------------------------------------------------
+_derive_pkg() {
+  printf '%s' "$1" | tr '[:upper:]' '[:lower:]' \
+    | sed -e 's/[^a-z0-9]\{1,\}/_/g' -e 's/^_//' -e 's/_$//'
+}
+_derive_struct() {
+  printf '%s' "$1" | sed -e 's/[^A-Za-z0-9]\{1,\}/ /g' \
+    | awk '{for(i=1;i<=NF;i++) printf "%s%s", toupper(substr($i,1,1)), substr($i,2); print ""}'
+}
+
+# --- the names ---------------------------------------------------------------
+PLUGIN_NAME="Bari 206"
+VENDOR="Novoyuuparosk"
+EMAIL="mikkeli@novoyuuparosk.org"
+AUTHOR="Mikkeli Matlock"
+HOMEPAGE="https://github.com/mikkeli/codename-206"
+DESCRIPTION="A VST3/CLAP multiband compressor/limiter with a custom gain-curve display"
+
+# What the plugin does *now*. No codename, no development stage.
+CLAP_DESCRIPTION="Multiband compressor/limiter (stage 3: 3-band + 'All' channel)"
+
+# --- frozen identity ---------------------------------------------------------
+# Hosts key saved projects and presets off these two. Never move them after the
+# first release: every existing session silently loses the plugin.
+CLAP_ID="org.novoyuuparosk.bari-206"
+VST3_CLASS_ID="Bari206Multiband"
+
+# --- fixed at repo creation --------------------------------------------------
+# The repo keeps its development codename while the plugin carries the product
+# name. Recorded only so it can be kept out of user-facing text.
+CODENAME="codename-206"
+
+LIB_FILE="src/lib.rs"
+PARAMS_FILE="src/params.rs"
+
+# --- derived unless overridden -----------------------------------------------
+# PKG, STRUCT and PARAMS_STRUCT all derive correctly from PLUGIN_NAME here, so
+# none is pinned. DISPLAY defaults to PLUGIN_NAME.
+: "${AUTHOR:=$VENDOR}"
+: "${DISPLAY:=$PLUGIN_NAME}"
+: "${PKG:=$(_derive_pkg "$PLUGIN_NAME")}"
+: "${STRUCT:=$(_derive_struct "$PLUGIN_NAME")}"
+: "${PARAMS_STRUCT:=${STRUCT}Params}"
+
+# --- retired spellings -------------------------------------------------------
+STALE="codename_206
+Codename 206
+Codename206
+Codename206Params
+Codename206Maxi!
+206 prototype
+com.mikkeli.codename-206
+bari_206
+Bari 206
+Bari206
+Bari206Params
+Bari206Multiband
+org.novoyuuparosk.bari-206"

tools/check-branding.sh

@@ -0,0 +1,188 @@
+#!/bin/sh
+# SPDX-License-Identifier: GPL-3.0-or-later
+# check-branding.sh - verify the plugin's branding/identity strings agree everywhere.
+#
+# Plugin branding is duplicated across the build manifest, the bundler manifest,
+# the source, the docs and (once you add one) the deploy script. Nothing makes
+# them agree, so a rename drifts silently: the bundle builds under one name and
+# the deploy script looks for another. This asserts they match, and that the
+# identity constants are legal.
+#
+# In a template this matters more than usual: renaming is the first thing you do
+# with this repo, and it touches every file below. Run this immediately after,
+# and the STALE machinery will list whatever you missed.
+#
+# Usage: sh tools/check-branding.sh          (exit 0 = consistent, 1 = drift found)
+#
+# The canonical identity lives in branding.conf, shared with brand-plugin.sh.
+# Edit it there, then run this to find every copy that still holds the old value.
+
+set -u
+# Resolve the repo root: these live in tools/, every path they touch is
+# repo-relative, and they must behave the same wherever they are invoked from.
+cd "$(dirname "$0")/.." || exit 1
+
+if [ ! -f tools/branding.conf ]; then
+  printf 'tools/branding.conf not found\n' >&2
+  exit 1
+fi
+# shellcheck disable=SC1091
+. ./tools/branding.conf
+
+# Every canonical spelling concatenated, for the substring test below.
+CANONICAL_BLOB="$PKG
+$DESCRIPTION
+$CLAP_DESCRIPTION
+$STRUCT
+$PARAMS_STRUCT
+$DISPLAY
+$PLUGIN_NAME
+$VENDOR
+$EMAIL
+$HOMEPAGE
+$CLAP_ID
+$VST3_CLASS_ID"
+
+pass=0; fail=0; skip=0
+ok()   { pass=$((pass+1)); printf '  ok    %s\n' "$1"; }
+bad()  { fail=$((fail+1)); printf '  FAIL  %s\n' "$1"; [ $# -gt 1 ] && printf '        %s\n' "$2"; return 0; }
+note() { skip=$((skip+1)); printf '  skip  %s\n' "$1"; }
+# Reported for awareness only - never counted, never fails the run.
+info() { printf '  --    %s\n' "$1"; }
+
+# has FILE PATTERN -> fixed-string search
+has() { grep -qF "$2" "$1" 2>/dev/null; }
+
+check() { # check LABEL FILE LITERAL
+  if [ ! -f "$2" ]; then bad "$1" "missing file: $2"; return; fi
+  if has "$2" "$3"; then ok "$1"; else bad "$1" "$2 does not contain: $3"; fi
+}
+
+# Same as check, but a missing file is "not applicable yet" rather than drift.
+# The template ships without a deploy script; this starts checking once you add one.
+opt_check() { # opt_check LABEL FILE LITERAL
+  if [ ! -f "$2" ]; then note "$1 ($2 not present)"; return; fi
+  if has "$2" "$3"; then ok "$1"; else bad "$1" "$2 does not contain: $3"; fi
+}
+
+printf 'branding check (canonical: %s / "%s")\n\n' "$PKG" "$DISPLAY"
+
+# --- consistency: every site in the table holds its resolved literal ----------
+# The table is data, so adding a site is a row rather than a shell edit, and the
+# same script runs unmodified across every plugin built from this template.
+SITES="tools/branding-sites.tsv"
+if [ ! -f "$SITES" ]; then
+  bad "site table" "$SITES not found - run tools/brand-plugin.sh to generate it"
+else
+  printf 'sites\n'
+  while IFS="$(printf '\t')" read -r kind owner file pattern; do
+    case "$kind" in ''|\#*) continue ;; esac
+    [ -n "$pattern" ] || continue
+    label="$owner"
+    if [ ! -f "$file" ]; then
+      case "$kind" in
+        opt) note "$label ($file not present)" ;;
+        *)   bad  "$label" "missing file: $file" ;;
+      esac
+      continue
+    fi
+    if has "$file" "$pattern"; then ok "$label"
+    else bad "$label" "$file does not contain: $pattern"; fi
+  done < "$SITES"
+fi
+
+# --- validity: rules the table cannot express --------------------------------
+printf '\nvalidity\n'
+
+# VST3 class IDs are a fixed 16-byte array. A wrong length is a compile error,
+# but saying so here is clearer than reading rustc on it.
+n=$(printf '%s' "$VST3_CLASS_ID" | wc -c | tr -d ' ')
+if [ "$n" -eq 16 ]; then ok "VST3_CLASS_ID is 16 bytes"
+else bad "VST3_CLASS_ID is 16 bytes" "got $n bytes: \"$VST3_CLASS_ID\""; fi
+
+# CLAP IDs are reverse-DNS by convention and compared verbatim by hosts, so a
+# stray space or capital is a silent identity change between machines.
+case "$CLAP_ID" in
+  *\ *|*[A-Z]*) bad "CLAP_ID is reverse-DNS safe" "no spaces or capitals allowed: \"$CLAP_ID\"" ;;
+  *.*)          ok  "CLAP_ID is reverse-DNS safe" ;;
+  *)            bad "CLAP_ID is reverse-DNS safe" "expected dotted reverse-DNS, got: \"$CLAP_ID\"" ;;
+esac
+
+# An overridden package name is legitimate - the derivation is sometimes invalid
+# - but a display rename that forgot the package is not, and looks identical
+# from here. Reported, never failed.
+derived_pkg=$(_derive_pkg "$PLUGIN_NAME")
+[ "$PKG" = "$derived_pkg" ] || info "PKG \"$PKG\" differs from the derivation of PLUGIN_NAME (\"$derived_pkg\") - fine if deliberate"
+
+# CLAP_DESCRIPTION is shown to users in a host's plugin browser. "Free of
+# development history" is a judgement a script cannot make, but the failure it
+# produces is mechanical: a retired name or the repo codename surviving in it.
+hygiene_hits=""
+while IFS= read -r s_entry; do
+  [ -n "$s_entry" ] || continue
+  case "$CANONICAL_BLOB" in *"$s_entry"*) continue ;; esac
+  case "$CLAP_DESCRIPTION" in *"$s_entry"*) hygiene_hits="$hygiene_hits \"$s_entry\"" ;; esac
+done <<HYGIENE_LIST
+$STALE
+$CODENAME
+HYGIENE_LIST
+if [ -z "$hygiene_hits" ]; then ok "CLAP_DESCRIPTION carries no retired name or codename"
+else bad "CLAP_DESCRIPTION carries no retired name or codename" "found:$hygiene_hits"; fi
+
+printf '\nstale spellings\n'
+# File list for the scan below. Prefer git, so build output and any vendored
+# tree stay out of it. Fall back to find when this is not a checkout - an
+# exported tarball, or a CI step that fetched without git metadata - because
+# `git ls-files` there returns nothing, and an empty list would report every
+# stale spelling as absent. A check that passes hardest when it can see least
+# is worse than no check.
+if git rev-parse --is-inside-work-tree >/dev/null 2>&1; then
+  file_list() { git ls-files; }
+  scan_source="git"
+else
+  file_list() { find . -path ./.git -prune -o -path ./target -prune -o -type f -print | sed 's|^\./||'; }
+  scan_source="find (not a git checkout)"
+fi
+info "scanning tracked files via $scan_source"
+# Fed by here-doc rather than a pipe on purpose: a piped `while` runs in a
+# subshell, and the pass/fail counters it increments would be discarded.
+while IFS= read -r s; do
+  [ -n "$s" ] || continue
+
+  # Still part of a canonical value? Then it is current branding, not a leftover.
+  # This is what lets the list ship pre-seeded: entries arm themselves as you
+  # rename. Substring, not equality, because placeholders nest - "your-domain"
+  # lives inside the canonical CLAP_ID, and "YOUR-USERNAME" inside the homepage.
+  # Over-skipping is the safe direction: a false FAIL on a name you still use
+  # would train you to ignore this section.
+  case "$CANONICAL_BLOB" in
+    *"$s"*) note "\"$s\" (still canonical)"; continue ;;
+  esac
+
+  # These two name every retired spelling by definition - the STALE list lives in
+  # branding.conf and this script reads it - so neither can ever be a real hit.
+  hits=$(file_list 2>/dev/null | while read -r f; do
+           case "$f" in tools/check-branding.sh|tools/branding.conf) continue ;; esac
+           [ -f "$f" ] && grep -lF "$s" "$f" 2>/dev/null
+         done)
+  if [ -z "$hits" ]; then ok "no occurrences of \"$s\""
+  else bad "no occurrences of \"$s\"" "still present in: $(echo "$hits" | tr '\n' ' ')"; fi
+done <<STALE_LIST
+$STALE
+STALE_LIST
+
+# Template scaffolding, not drift: TODOs are legitimate while you are still
+# building. Reported so a finished plugin does not quietly ship with them.
+# `grep -c` prints 0 AND exits 1 when there are no matches, so `|| echo 0`
+# would append a second zero and make the count unparseable. Swallow the
+# status instead, and default an empty result (missing file) to zero.
+todos=$(grep -c 'TODO' src/lib.rs 2>/dev/null || :)
+[ -n "$todos" ] || todos=0
+printf '\nscaffolding\n'
+if [ "$todos" -eq 0 ]; then ok "no TODO markers left in src/lib.rs"
+else info "$todos TODO marker(s) still in src/lib.rs (not a failure)"; fi
+
+printf '\n%d passed, %d failed' "$pass" "$fail"
+[ "$skip" -gt 0 ] && printf ', %d skipped' "$skip"
+printf '\n'
+[ "$fail" -eq 0 ] || exit 1

xtask/src/main.rs

@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-3.0-or-later
 fn main() -> nih_plug_xtask::Result<()> {
     nih_plug_xtask::main()
 }