feat: stable note tracking, NOTE pitch source and unsure fallback

Producers found the tracked plugins jumpy: the shared tracker switched notes
after 10 ms and retuned every 5 ms, so growls and formant basses flickered
and every tracked plugin acted on wrong notes.

Shared tracker (common-dsp):
- A new note needs a steady read for 40 ms; an octave down 80 ms, an octave
  up 200 ms (an octave-up read still fits the note's period and counts as
  agreeing). Inside a note the tuning only moves past a 0.25 semitone
  deadband. Follow bends keeps the old fast behaviour as an option.
- A trust score turns the note unsure while reads disagree; Tracker::active
  and NoteState report it, and Fallback latches "step back" across note ends.
- Notes end when the window start stays below the gate's release level for
  20 ms, so short gaps between notes are seen without waiting for the gate.
- PitchSource replaces the old (midi, gate, glide) arguments: Audio, MIDI or
  Note mode (a set note, no detection), plus a key lock (minor, major, root
  only) that snaps reads to the key.
- stems.rs: synthetic stems (growls, wobble, reese, formant, 808 slide,
  layered drop, noise riser) and a score; examples/tracker_report scores the
  corpus or real WAV stems. On the corpus the old behaviour makes up to 28
  extra note starts per second; the stable default makes none.

Plugins:
- Anvil, Lathe, Temper, Knurl, Planish, Braze and Forge gain the NOTE pitch
  source, the key lock and Follow bends (shared common-params crate and a
  shared header switch in common-ui).
- Unsure tracking: Anvil brings the original sub back in place of the sine,
  Lathe passes the audio through, Knurl fades its texture out; Temper,
  Planish and Braze hold their last sure tuning. Readouts show the note only
  when it is sure.
- Anvil gains Mode: Replace or Enhance (keeps the original sub and adds the
  sine under it).
- Planish slides its band edges over 6 ms on a new note instead of snapping.
- Ballast defaults to Grid parts, which need no tracking.

Cargo.lock

@@ -108,11 +108,15 @@ checksum = "4e7648175b45a9a48536d676f68d918270699102aa8dab5496df06904c914600"
 [[package]]
 name = "common-dsp"
 version = "0.1.0"
+dependencies = [
+ "serde",
+]
 
 [[package]]
 name = "common-ui"
 version = "0.1.0"
 dependencies = [
+ "common-dsp",
  "egui",
 ]
 

Cargo.toml

@@ -1,7 +1,7 @@
 [workspace]
 resolver = "2"
 members = ["plugins/common/ui", "plugins/common/dsp", "plugins/anvil/core", "plugins/anvil/ui", "plugins/lathe/core", "plugins/lathe/ui", "plugins/temper/core", "plugins/temper/ui", "plugins/weld/core", "plugins/weld/ui", "plugins/knurl/core", "plugins/knurl/ui", "plugins/planish/core", "plugins/planish/ui", "plugins/braze/core", "plugins/braze/ui", "plugins/quench/core", "plugins/quench/ui", "plugins/ballast/core", "plugins/ballast/ui", "plugins/forge/core", "plugins/forge/ui", "plugins/crucible/core", "plugins/crucible/ui", "plugins/rivet/core", "plugins/rivet/midi", "plugins/rivet/preview", "plugins/rivet/app", "plugins/patina/core", "plugins/patina/render", "plugins/patina/ui"]
-exclude = ["plugins/rivet/plugin", "tools/editor-check", "plugins/patina/plugin", "plugins/anvil/plugin", "plugins/crucible/plugin", "plugins/lathe/plugin", "plugins/temper/plugin", "plugins/weld/plugin", "plugins/knurl/plugin", "plugins/planish/plugin"]
+exclude = ["plugins/common/params", "plugins/rivet/plugin", "tools/editor-check", "plugins/patina/plugin", "plugins/anvil/plugin", "plugins/crucible/plugin", "plugins/lathe/plugin", "plugins/temper/plugin", "plugins/weld/plugin", "plugins/knurl/plugin", "plugins/planish/plugin"]
 
 [workspace.package]
 edition = "2021"

plugins/anvil/core/src/lib.rs

@@ -10,6 +10,10 @@
 //! only the harmonics the patch lacks are filled: a harmonic the patch already has would
 //! meet the added one at an unrelated phase and could cancel.
 //!
+//! The sine only plays while the note is sure. While tracking is unsure, the original sub
+//! comes back in its place (Replace) or the added sine fades out (Enhance), so a wrong guess
+//! never plays a wrong sub note.
+//!
 //! Kick lock reads the kick from the sidechain. Hits are found on the undelayed sidechain,
 //! so with the lookahead each hit ducks the sub exactly when the delayed kick plays, and
 //! restarts the sub's phase at the kick plus an offset, also before the kick. The audition
@@ -18,9 +22,9 @@
 mod settings;
 use common_dsp::meter::HarmonicMeter;
 use common_dsp::svf::{Svf, SvfCoef};
-use common_dsp::tracker::{NoteEvent, Tracker, TrackerConfig};
+use common_dsp::tracker::{Fallback, NoteEvent, Tracker, TrackerConfig};
 use common_dsp::{coefficient, db_to_gain, hz_to_midi, midi_to_hz, Biquad, Crossover};
-pub use settings::{Settings, Source, KICK_OFFSET_MAX};
+pub use settings::{Mode, Settings, Source, KICK_OFFSET_MAX};
 use std::f32::consts::TAU;
 
 /// Detectable fundamental range. The lowest sets the lookahead (two periods).
@@ -30,6 +34,8 @@ pub const SCOPE: usize = 256;
 const ATTACK_MS: f32 = 2.;
 const RELEASE_MS: f32 = 15.;
 const CROSSFADE_MS: f32 = 3.;
+/// Crossfade between the sine and the original sub when tracking turns unsure or sure.
+const TRUST_MS: f32 = 15.;
 /// Highest Ghost harmonic. Harmonic 10 of a 30 Hz sub is 300 Hz.
 pub const GHOST_TOP: usize = 10;
 /// Ghost harmonics shown and generated: 2..=GHOST_TOP.
@@ -76,6 +82,8 @@ pub struct AnalyzerFrame {
     pub hz: f32,
     /// MIDI note of the current sub, rounded.
     pub note: Option<u8>,
+    /// Tracking is unsure: the original sub plays instead of the sine.
+    pub neutral: bool,
     pub low_db: f32,
     pub sub_db: f32,
     /// Harmonics 2..=GHOST_TOP of the current note, peak dB relative to the sub: what the
@@ -106,6 +114,7 @@ impl Default for AnalyzerFrame {
         Self {
             hz: 0.,
             note: None,
+            neutral: false,
             low_db: -120.,
             sub_db: -120.,
             patch_harmonics: [-120.; GHOST_COUNT],
@@ -308,6 +317,11 @@ pub struct Engine {
     keep: f32,
     output: f32,
     bypass: f32,
+    fallback: Fallback,
+    neutral: bool,
+    /// 1 while the sine plays, 0 while the original sub stands in for it.
+    trust: f32,
+    trust_coef: f32,
     meter_coef: f32,
     low_power: f32,
     sub_power: f32,
@@ -355,6 +369,10 @@ impl Engine {
             keep: 0.,
             output: 1.,
             bypass: 0.,
+            fallback: Fallback::default(),
+            neutral: false,
+            trust: 1.,
+            trust_coef: coefficient(rate, TRUST_MS / 3.),
             meter_coef: coefficient(rate, 150.),
             low_power: 0.,
             sub_power: 0.,
@@ -397,7 +415,7 @@ impl Engine {
         }
         if self
             .tracker
-            .set(s.source == Source::Midi, s.gate, s.glide > 0.)
+            .set(s.pitch.source(s.source.mode(), s.gate, s.glide > 0.))
         {
             self.synth.voice.releasing = true;
         }
@@ -416,6 +434,9 @@ impl Engine {
         }
         self.tracker.reset();
         self.synth = Synth::default();
+        self.fallback.reset();
+        self.neutral = false;
+        self.trust = 1.;
         self.low_env = 0.;
         self.low_power = 0.;
         self.sub_power = 0.;
@@ -638,6 +659,7 @@ impl Engine {
         };
         let (synth, settings) = (&mut self.synth, &self.settings);
         self.tracker.process(mono, |e| synth.event(settings, e));
+        self.neutral = self.fallback.neutral(self.tracker.state());
         let len = self.delay.len();
         self.delay[self.delay_at] = x;
         self.delay_at = (self.delay_at + 1) % len;
@@ -683,8 +705,10 @@ impl Engine {
         let duck = self.kick_events();
         self.update_fill();
         let (sub, ghost) = self.oscillator();
-        let sub = sub * self.level * shape * duck;
-        let generated = sub + ghost * self.level * shape * duck;
+        self.trust += (f32::from(!self.neutral) - self.trust) * self.trust_coef;
+        let gain = self.level * shape * duck * self.trust;
+        let sub = sub * gain;
+        let generated = sub + ghost * gain;
         if self.settings.kick_lock {
             let kick_low = self.kick.low.process(kick_late);
             self.measure_kick(kick_low, sub);
@@ -699,11 +723,16 @@ impl Engine {
             self.scope_sub[self.scope_at] = generated;
             self.scope_at = (self.scope_at + 1) % (2 * SCOPE);
         }
+        // Replace keeps `keep` of the original, and all of it while the sine is out.
+        let keep = match s.mode {
+            Mode::Replace => self.keep + (1. - self.keep) * (1. - self.trust),
+            Mode::Enhance => 1.,
+        };
         let wet = |l: f32, h: f32| {
             if monitor.solo {
                 generated
             } else {
-                h + self.keep * l + generated
+                h + keep * l + generated
             }
         };
         let w = [wet(l0, h0), wet(l1, h1)];
@@ -736,6 +765,7 @@ impl Engine {
             kick_sum_db: self.kick.sum_db,
             kick_offset: self.kick.offset,
             audition_sums: self.kick.sums,
+            neutral: self.neutral,
             ..AnalyzerFrame::default()
         };
         let sub = self.level.max(1e-6);
@@ -751,7 +781,7 @@ impl Engine {
             f.ghost_harmonics[i] = rel(self.fill[i] * sub);
         }
         let v = self.synth.voice;
-        if v.amp > 0. && !v.releasing {
+        if v.amp > 0. && !v.releasing && !self.neutral {
             f.hz = v.hz;
             f.note = Some(hz_to_midi(v.hz).round().clamp(0., 127.) as u8);
         }

plugins/anvil/core/src/settings.rs

@@ -1,4 +1,5 @@
 //! Host-independent controls. Levels in dB, times in milliseconds, frequencies in Hz.
+use common_dsp::tracker::{Pitch, PitchMode};
 use serde::{Deserialize, Serialize};
 
 #[derive(Debug, Clone, Copy, Serialize, Deserialize, PartialEq, Eq, Default)]
@@ -8,12 +9,45 @@ pub enum Source {
     Audio,
     /// Notes come from MIDI note input; the audio only supplies the band above the split.
     Midi,
+    /// Note starts are detected, the pitch is the set note: nothing is guessed.
+    Note,
+}
+impl Source {
+    pub fn mode(self) -> PitchMode {
+        match self {
+            Source::Audio => PitchMode::Audio,
+            Source::Midi => PitchMode::Midi,
+            Source::Note => PitchMode::Note,
+        }
+    }
+    pub fn from_mode(mode: PitchMode) -> Self {
+        match mode {
+            PitchMode::Audio => Source::Audio,
+            PitchMode::Midi => Source::Midi,
+            PitchMode::Note => Source::Note,
+        }
+    }
+}
+
+/// What happens to the original sub.
+#[derive(Debug, Clone, Copy, Serialize, Deserialize, PartialEq, Eq, Default)]
+pub enum Mode {
+    /// The band below the split is replaced by the clean sine (plus Keep of the original).
+    #[default]
+    Replace,
+    /// The original sub stays, and the sine is added under it for weight.
+    Enhance,
 }
 
 #[derive(Debug, Clone, Copy, Serialize, Deserialize, PartialEq)]
 #[serde(deny_unknown_fields)]
 pub struct Settings {
     pub source: Source,
+    /// Note mode's note, the key lock and Follow bends.
+    #[serde(default)]
+    pub pitch: Pitch,
+    #[serde(default)]
+    pub mode: Mode,
     /// Peak level of the new sub in dBFS, the same for every note.
     pub level: f32,
     /// Crossover frequency: below it the original sub is replaced.
@@ -75,6 +109,8 @@ impl Default for Settings {
     fn default() -> Self {
         Self {
             source: Source::Audio,
+            pitch: Pitch::default(),
+            mode: Mode::Replace,
             level: -9.,
             split: 90.,
             dynamics: 0.,
@@ -99,6 +135,7 @@ impl Default for Settings {
 }
 impl Settings {
     pub fn validate(&self) -> Result<(), &'static str> {
+        self.pitch.validate()?;
         let finite = [
             self.level,
             self.split,

plugins/anvil/core/tests/dsp.rs

@@ -1,4 +1,4 @@
-use anvil_core::{Engine, Monitor, Settings, Source};
+use anvil_core::{Engine, Mode, Monitor, Settings, Source};
 use common_dsp::Saw;
 
 const RATE: f32 = 48000.;
@@ -488,3 +488,73 @@ fn the_audition_finds_where_kick_and_sub_sum() {
         );
     }
 }
+
+#[test]
+fn unsure_tracking_brings_back_the_original_sub() {
+    let (mut e, l) = engine(Settings::default());
+    // A clear note, then low noise the tracker cannot read.
+    let mut x = notes(&[(0.1, 0.6, 55., 0.5)], 0.6);
+    let mut seed = 3u32;
+    let mut lp = 0f32;
+    for _ in 0..seconds(1.5) {
+        seed ^= seed << 13;
+        seed ^= seed >> 17;
+        seed ^= seed << 5;
+        lp += 0.05 * ((seed as f32 / u32::MAX as f32 - 0.5) - lp);
+        x.push(4. * lp);
+    }
+    let solo = render(&mut e, &x, true);
+    let sine = rms(&solo[seconds(0.3) + l..seconds(0.5) + l]);
+    let unsure = rms(&solo[seconds(1.5) + l..seconds(2.0) + l]);
+    assert!(
+        db(unsure) < db(sine) - 40.,
+        "{} vs {}",
+        db(unsure),
+        db(sine)
+    );
+    // The full output carries the original low band again.
+    let (mut e, l) = engine(Settings::default());
+    let y = render(&mut e, &x, false);
+    let a = rms(&x[seconds(1.5)..seconds(2.0)]);
+    let b = rms(&y[seconds(1.5) + l..seconds(2.0) + l]);
+    assert!((db(a) - db(b)).abs() < 1., "{} vs {}", db(a), db(b));
+}
+
+#[test]
+fn enhance_keeps_the_original_and_adds_the_sine() {
+    let x = tones(&[(55., 0.3)], 1.2);
+    for (mode, keeps) in [(Mode::Replace, false), (Mode::Enhance, true)] {
+        let (mut e, l) = engine(Settings {
+            mode,
+            octave: -1,
+            ..Settings::default()
+        });
+        let y = render(&mut e, &x, false);
+        // Whole cycles of 27.5 Hz: 0.4 s.
+        let w = &y[seconds(0.5) + l..seconds(0.9) + l];
+        let original = amplitude(w, 55.);
+        let added = amplitude(w, 27.5);
+        assert!((db(added) + 9.).abs() < 1., "{mode:?}: {}", db(added));
+        if keeps {
+            assert!((db(original) - db(0.3)).abs() < 1., "{}", db(original));
+        } else {
+            assert!(db(original) < db(0.3) - 12., "{}", db(original));
+        }
+    }
+}
+
+#[test]
+fn note_mode_plays_the_set_note_whatever_the_audio() {
+    let (mut e, l) = engine(Settings {
+        source: Source::Note,
+        pitch: common_dsp::tracker::Pitch {
+            note: 29,
+            ..Default::default()
+        },
+        ..Settings::default()
+    });
+    let x = notes(&[(0.1, 1.1, 61.74, 0.5)], 1.3);
+    let y = render(&mut e, &x, true);
+    let f = frequency(&y[seconds(0.3) + l..seconds(1.0) + l]);
+    assert!((f / 43.654 - 1.).abs() < 0.005, "{f}");
+}

plugins/anvil/plugin/Cargo.lock

@@ -77,6 +77,7 @@ dependencies = [
  "anvil-core",
  "anvil-ui",
  "clap-sys",
+ "common-params",
  "crossbeam-queue",
  "nih_plug",
  "nih_plug_egui",
@@ -340,11 +341,23 @@ dependencies = [
 [[package]]
 name = "common-dsp"
 version = "0.1.0"
+dependencies = [
+ "serde",
+]
+
+[[package]]
+name = "common-params"
+version = "0.1.0"
+dependencies = [
+ "common-dsp",
+ "nih_plug",
+]
 
 [[package]]
 name = "common-ui"
 version = "0.1.0"
 dependencies = [
+ "common-dsp",
  "egui",
 ]
 

plugins/anvil/plugin/Cargo.toml

@@ -13,6 +13,7 @@ crate-type = ["cdylib", "rlib"]
 nih_plug = { git = "https://github.com/robbert-vdh/nih-plug.git", rev = "de421011f41a6d10fc8c7a6084e4f4dee0143683", default-features = false }
 nih_plug_egui = { git = "https://github.com/robbert-vdh/nih-plug.git", rev = "de421011f41a6d10fc8c7a6084e4f4dee0143683" }
 anvil-core = { path = "../core" }
+common-params = { path = "../../common/params" }
 anvil-ui = { path = "../ui" }
 crossbeam-queue = "0.3"
 

plugins/anvil/plugin/src/params.rs

@@ -1,4 +1,5 @@
-use anvil_core::{Settings, Source, KICK_OFFSET_MAX};
+use anvil_core::{Mode, Settings, Source, KICK_OFFSET_MAX};
+use common_params::PitchParams;
 use nih_plug::prelude::*;
 use nih_plug_egui::EguiState;
 use std::sync::Arc;
@@ -10,6 +11,49 @@ pub enum SourceParam {
     #[id = "midi"]
     #[name = "MIDI"]
     Midi,
+    #[id = "note"]
+    Note,
+}
+impl From<SourceParam> for Source {
+    fn from(s: SourceParam) -> Self {
+        match s {
+            SourceParam::Audio => Source::Audio,
+            SourceParam::Midi => Source::Midi,
+            SourceParam::Note => Source::Note,
+        }
+    }
+}
+impl From<Source> for SourceParam {
+    fn from(s: Source) -> Self {
+        match s {
+            Source::Audio => SourceParam::Audio,
+            Source::Midi => SourceParam::Midi,
+            Source::Note => SourceParam::Note,
+        }
+    }
+}
+#[derive(Enum, Debug, PartialEq, Eq, Clone, Copy)]
+pub enum ModeParam {
+    #[id = "replace"]
+    Replace,
+    #[id = "enhance"]
+    Enhance,
+}
+impl From<ModeParam> for Mode {
+    fn from(m: ModeParam) -> Self {
+        match m {
+            ModeParam::Replace => Mode::Replace,
+            ModeParam::Enhance => Mode::Enhance,
+        }
+    }
+}
+impl From<Mode> for ModeParam {
+    fn from(m: Mode) -> Self {
+        match m {
+            Mode::Replace => ModeParam::Replace,
+            Mode::Enhance => ModeParam::Enhance,
+        }
+    }
 }
 fn linear(name: &str, v: f32, min: f32, max: f32, unit: &'static str) -> FloatParam {
     FloatParam::new(name, v, FloatRange::Linear { min, max }).with_unit(unit)
@@ -20,6 +64,10 @@ pub struct AnvilParams {
     pub editor: Arc<EguiState>,
     #[id = "source"]
     pub source: EnumParam<SourceParam>,
+    #[nested(group = "Pitch")]
+    pub pitch: PitchParams,
+    #[id = "mode"]
+    pub mode: EnumParam<ModeParam>,
     #[id = "level"]
     pub level: FloatParam,
     #[id = "split"]
@@ -65,6 +113,8 @@ impl Default for AnvilParams {
         Self {
             editor: EguiState::from_size(anvil_ui::WIDTH, anvil_ui::HEIGHT),
             source: EnumParam::new("Pitch source", SourceParam::Audio),
+            pitch: PitchParams::default(),
+            mode: EnumParam::new("Mode", ModeParam::Replace),
             level: linear("Sub level", d.level, -30., 0., " dBFS"),
             split: FloatParam::new(
                 "Split",
@@ -114,10 +164,9 @@ impl Default for AnvilParams {
 impl AnvilParams {
     pub fn settings(&self) -> Settings {
         Settings {
-            source: match self.source.value() {
-                SourceParam::Audio => Source::Audio,
-                SourceParam::Midi => Source::Midi,
-            },
+            source: self.source.value().into(),
+            pitch: self.pitch.pitch(),
+            mode: self.mode.value().into(),
             level: self.level.value(),
             split: self.split.value(),
             dynamics: self.dynamics.value(),
@@ -206,14 +255,16 @@ impl AnvilParams {
             });
         }
         once(new.source != old.source, &|| {
-            let v = match new.source {
-                Source::Audio => SourceParam::Audio,
-                Source::Midi => SourceParam::Midi,
-            };
             setter.begin_set_parameter(&self.source);
-            setter.set_parameter(&self.source, v);
+            setter.set_parameter(&self.source, new.source.into());
             setter.end_set_parameter(&self.source);
         });
+        once(new.mode != old.mode, &|| {
+            setter.begin_set_parameter(&self.mode);
+            setter.set_parameter(&self.mode, new.mode.into());
+            setter.end_set_parameter(&self.mode);
+        });
+        self.pitch.apply(setter, &old.pitch, &new.pitch);
     }
     fn continuous(&self, i: usize) -> &FloatParam {
         [

plugins/anvil/ui/src/lib.rs

@@ -228,13 +228,9 @@ pub fn show(ui: &mut egui::Ui, settings: &mut Settings, state: &mut State) {
             state.phone = !state.phone;
         }
         ui.separator();
-        for (source, label) in [(Source::Midi, "MIDI"), (Source::Audio, "AUDIO")] {
-            let r = ui.selectable_label(settings.source == source, RichText::new(label).size(13.));
-            if r.clicked() {
-                settings.source = source;
-            }
-        }
-        caption(ui, "PITCH FROM");
+        let mut mode = settings.source.mode();
+        pitch_from(ui, &mut mode, &mut settings.pitch);
+        settings.source = Source::from_mode(mode);
     });
     ui.add_space(6.);
     let frame = state.analyzer;
@@ -284,10 +280,7 @@ fn note_panel(ui: &mut egui::Ui, settings: &Settings, frame: &AnalyzerFrame) {
         RichText::new(format!(
             "{:.0} ms lookahead · {}",
             frame.latency as f32 / frame.sample_rate * 1000.,
-            match settings.source {
-                Source::Audio => "detecting pitch",
-                Source::Midi => "following MIDI notes",
-            }
+            pitch_status(settings.source.mode(), &settings.pitch)
         ))
         .size(12.)
         .color(MUTED),

plugins/ballast/core/src/lib.rs

@@ -11,7 +11,7 @@
 mod settings;
 use common_dsp::loudness::{lufs, KWeighting};
 use common_dsp::svf::{Svf, SvfCoef};
-use common_dsp::tracker::{NoteEvent, Tracker, TrackerConfig};
+use common_dsp::tracker::{NoteEvent, PitchMode, PitchSource, Tracker, TrackerConfig};
 use common_dsp::{coefficient, db_to_gain, gain_to_db};
 pub use settings::{
     Grid, Segment, Settings, Source, FROM_MAX, FROM_MIN, RANGE_MAX, TARGET_MAX, TARGET_MIN,
@@ -216,7 +216,15 @@ impl Engine {
     }
     pub fn set_settings(&mut self, s: Settings) -> Result<(), &'static str> {
         s.validate()?;
-        self.tracker.set(s.source == Source::Midi, s.gate, false);
+        self.tracker.set(PitchSource {
+            mode: if s.source == Source::Midi {
+                PitchMode::Midi
+            } else {
+                PitchMode::Audio
+            },
+            gate_db: s.gate,
+            ..PitchSource::default()
+        });
         if s.from != self.settings.from || self.fresh {
             self.from_coef = if s.from > FROM_MIN {
                 SvfCoef::highpass(self.rate, s.from, Q)

plugins/ballast/core/src/settings.rs

@@ -22,9 +22,10 @@ pub enum Source {
 #[derive(Debug, Clone, Copy, Serialize, Deserialize, PartialEq, Eq, Default)]
 pub enum Segment {
     /// Every note start.
-    #[default]
     Notes,
     /// Every line of the host's beat grid, so a patch change on the same note counts too.
+    /// The default: a switch-up lands on the grid, and the grid needs no note tracking.
+    #[default]
     Grid,
 }
 
@@ -91,7 +92,7 @@ impl Default for Settings {
     fn default() -> Self {
         Self {
             source: Source::Audio,
-            segment: Segment::Notes,
+            segment: Segment::Grid,
             grid: Grid::Quarter,
             target: -14.,
             amount: 100.,

plugins/ballast/core/tests/dsp.rs

@@ -117,6 +117,7 @@ fn note_starts_from_the_audio_cut_the_parts() {
     let mut e = Engine::new(RATE, 2).unwrap();
     e.set_settings(Settings {
         target,
+        segment: Segment::Notes,
         ..Settings::default()
     })
     .unwrap();
@@ -151,6 +152,7 @@ fn midi_note_starts_cut_legato_parts() {
     e.set_settings(Settings {
         target,
         source: Source::Midi,
+        segment: Segment::Notes,
         ..Settings::default()
     })
     .unwrap();

plugins/ballast/plugin/Cargo.lock

@@ -340,11 +340,15 @@ dependencies = [
 [[package]]
 name = "common-dsp"
 version = "0.1.0"
+dependencies = [
+ "serde",
+]
 
 [[package]]
 name = "common-ui"
 version = "0.1.0"
 dependencies = [
+ "common-dsp",
  "egui",
 ]
 

plugins/ballast/plugin/src/params.rs

@@ -88,7 +88,7 @@ impl Default for BallastParams {
         Self {
             editor: EguiState::from_size(ballast_ui::WIDTH, ballast_ui::HEIGHT),
             source: EnumParam::new("Note source", SourceParam::Audio),
-            segment: EnumParam::new("Parts from", SegmentParam::Notes),
+            segment: EnumParam::new("Parts from", SegmentParam::Grid),
             grid: EnumParam::new("Grid", grid_param(d.grid)),
             target: linear("Target", d.target, TARGET_MIN, TARGET_MAX, " LUFS"),
             amount: linear("Amount", d.amount, 0., 100., " %"),

plugins/braze/core/src/lib.rs

@@ -181,7 +181,9 @@ impl Engine {
     }
     pub fn set_settings(&mut self, s: Settings) -> Result<(), &'static str> {
         s.validate()?;
-        self.tracker.set(s.source == Source::Midi, s.gate, true);
+        // Unsure tracking sends no events, so the beating holds its last sure note.
+        self.tracker
+            .set(s.pitch.source(s.source.mode(), s.gate, true));
         if s.low_cut != self.settings.low_cut || self.fresh {
             let q = std::f32::consts::FRAC_1_SQRT_2;
             let hz = s.low_cut.min(0.45 * self.rate);
@@ -340,7 +342,7 @@ impl Engine {
             let beat_hz = self.tempo / 60. / s.rate.quarters();
             f.ratio = 1. + (beat_hz / (s.harmonic as f64 * hz as f64)) as f32;
         }
-        if self.tracker.sounding() && hz > 0. {
+        if self.tracker.active() && hz > 0. {
             f.note = Some(hz_to_midi(hz).round().clamp(0., 127.) as u8);
         }
         f

plugins/braze/core/src/settings.rs

@@ -1,4 +1,5 @@
 //! Host-independent controls. Levels in dB, amounts in percent, angles in degrees.
+use common_dsp::tracker::{Pitch, PitchMode};
 use serde::{Deserialize, Serialize};
 
 /// Highest harmonic the beat rate can be set on.
@@ -14,6 +15,24 @@ pub enum Source {
     Audio,
     /// Notes come from MIDI note input.
     Midi,
+    /// Note starts are detected, the pitch is the set note: nothing is guessed.
+    Note,
+}
+impl Source {
+    pub fn mode(self) -> PitchMode {
+        match self {
+            Source::Audio => PitchMode::Audio,
+            Source::Midi => PitchMode::Midi,
+            Source::Note => PitchMode::Note,
+        }
+    }
+    pub fn from_mode(mode: PitchMode) -> Self {
+        match mode {
+            PitchMode::Audio => Source::Audio,
+            PitchMode::Midi => Source::Midi,
+            PitchMode::Note => Source::Note,
+        }
+    }
 }
 
 /// One beat cycle lasts this note value.
@@ -75,6 +94,9 @@ impl Rate {
 #[serde(deny_unknown_fields)]
 pub struct Settings {
     pub source: Source,
+    /// Note mode's note, the key lock and Follow bends.
+    #[serde(default)]
+    pub pitch: Pitch,
     /// How long one beat cycle of `harmonic` lasts.
     pub rate: Rate,
     /// The harmonic that beats exactly at `rate`. Harmonic n beats n/harmonic times as fast.
@@ -100,6 +122,7 @@ impl Default for Settings {
     fn default() -> Self {
         Self {
             source: Source::Audio,
+            pitch: Pitch::default(),
             rate: Rate::Eighth,
             // Harmonic 4 sits above the low cut on every bass note, and on F1 it asks for
             // about 45 cents of detune, a usual reese spread.
@@ -117,6 +140,7 @@ impl Default for Settings {
 }
 impl Settings {
     pub fn validate(&self) -> Result<(), &'static str> {
+        self.pitch.validate()?;
         let finite = [
             self.depth,
             self.low_cut,

plugins/braze/plugin/Cargo.lock

@@ -189,6 +189,7 @@ dependencies = [
  "braze-core",
  "braze-ui",
  "clap-sys",
+ "common-params",
  "crossbeam-queue",
  "nih_plug",
  "nih_plug_egui",
@@ -340,11 +341,23 @@ dependencies = [
 [[package]]
 name = "common-dsp"
 version = "0.1.0"
+dependencies = [
+ "serde",
+]
+
+[[package]]
+name = "common-params"
+version = "0.1.0"
+dependencies = [
+ "common-dsp",
+ "nih_plug",
+]
 
 [[package]]
 name = "common-ui"
 version = "0.1.0"
 dependencies = [
+ "common-dsp",
  "egui",
 ]
 

plugins/braze/plugin/Cargo.toml

@@ -13,6 +13,7 @@ crate-type = ["cdylib", "rlib"]
 nih_plug = { git = "https://github.com/robbert-vdh/nih-plug.git", rev = "de421011f41a6d10fc8c7a6084e4f4dee0143683", default-features = false }
 nih_plug_egui = { git = "https://github.com/robbert-vdh/nih-plug.git", rev = "de421011f41a6d10fc8c7a6084e4f4dee0143683" }
 braze-core = { path = "../core" }
+common-params = { path = "../../common/params" }
 braze-ui = { path = "../ui" }
 crossbeam-queue = "0.3"
 

plugins/braze/plugin/src/params.rs

@@ -1,4 +1,5 @@
 use braze_core::{Rate, Settings, Source, HARMONIC_MAX, LOW_CUT_MAX};
+use common_params::PitchParams;
 use nih_plug::prelude::*;
 use nih_plug_egui::EguiState;
 use std::sync::Arc;
@@ -10,6 +11,26 @@ pub enum SourceParam {
     #[id = "midi"]
     #[name = "MIDI"]
     Midi,
+    #[id = "note"]
+    Note,
+}
+impl From<SourceParam> for Source {
+    fn from(s: SourceParam) -> Self {
+        match s {
+            SourceParam::Audio => Source::Audio,
+            SourceParam::Midi => Source::Midi,
+            SourceParam::Note => Source::Note,
+        }
+    }
+}
+impl From<Source> for SourceParam {
+    fn from(s: Source) -> Self {
+        match s {
+            Source::Audio => SourceParam::Audio,
+            Source::Midi => SourceParam::Midi,
+            Source::Note => SourceParam::Note,
+        }
+    }
 }
 #[derive(Enum, Debug, PartialEq, Eq, Clone, Copy)]
 pub enum RateParam {
@@ -70,6 +91,8 @@ pub struct BrazeParams {
     pub editor: Arc<EguiState>,
     #[id = "source"]
     pub source: EnumParam<SourceParam>,
+    #[nested(group = "Pitch")]
+    pub pitch: PitchParams,
     #[id = "rate"]
     pub rate: EnumParam<RateParam>,
     #[id = "harmonic"]
@@ -97,6 +120,7 @@ impl Default for BrazeParams {
         Self {
             editor: EguiState::from_size(braze_ui::WIDTH, braze_ui::HEIGHT),
             source: EnumParam::new("Pitch source", SourceParam::Audio),
+            pitch: PitchParams::default(),
             rate: EnumParam::new("Rate", to_param(d.rate)),
             harmonic: IntParam::new(
                 "Harmonic",
@@ -130,10 +154,8 @@ impl BrazeParams {
     pub fn settings(&self) -> Settings {
         let rate = self.rate.value();
         Settings {
-            source: match self.source.value() {
-                SourceParam::Audio => Source::Audio,
-                SourceParam::Midi => Source::Midi,
-            },
+            source: self.source.value().into(),
+            pitch: self.pitch.pitch(),
             rate: RATES
                 .iter()
                 .find(|(p, _)| *p == rate)
@@ -207,13 +229,10 @@ impl BrazeParams {
             }
         }
         if new.source != old.source {
-            let v = match new.source {
-                Source::Audio => SourceParam::Audio,
-                Source::Midi => SourceParam::Midi,
-            };
             setter.begin_set_parameter(&self.source);
-            setter.set_parameter(&self.source, v);
+            setter.set_parameter(&self.source, new.source.into());
             setter.end_set_parameter(&self.source);
         }
+        self.pitch.apply(setter, &old.pitch, &new.pitch);
     }
 }

plugins/braze/ui/src/lib.rs

@@ -202,13 +202,9 @@ pub fn show(ui: &mut egui::Ui, settings: &mut Settings, state: &mut State) {
             settings.bypass = !settings.bypass;
         }
         ui.separator();
-        for (source, label) in [(Source::Midi, "MIDI"), (Source::Audio, "AUDIO")] {
-            let r = ui.selectable_label(settings.source == source, RichText::new(label).size(13.));
-            if r.clicked() {
-                settings.source = source;
-            }
-        }
-        caption(ui, "PITCH FROM");
+        let mut mode = settings.source.mode();
+        pitch_from(ui, &mut mode, &mut settings.pitch);
+        settings.source = Source::from_mode(mode);
     });
     ui.add_space(6.);
     let frame = state.analyzer;
@@ -279,10 +275,7 @@ fn note_panel(ui: &mut egui::Ui, settings: &Settings, frame: &AnalyzerFrame) {
         RichText::new(format!(
             "{:.0} ms lookahead · {}",
             frame.latency as f32 / frame.sample_rate * 1000.,
-            match settings.source {
-                Source::Audio => "detecting pitch",
-                Source::Midi => "following MIDI notes",
-            }
+            pitch_status(settings.source.mode(), &settings.pitch)
         ))
         .size(12.)
         .color(MUTED),

plugins/common/dsp/Cargo.toml

@@ -5,3 +5,4 @@ edition.workspace = true
 license.workspace = true
 
 [dependencies]
+serde = { workspace = true }

plugins/common/dsp/examples/tracker_report.rs

@@ -0,0 +1,118 @@
+//! Scores the note tracker on bass stems.
+//!
+//! ```text
+//! cargo run -p common-dsp --release --example tracker_report
+//! cargo run -p common-dsp --release --example tracker_report -- [--sub] [--bends]
+//!     [--note F1] [--key free|minor|major|root] stem.wav ...
+//! ```
+//! Without files it scores the synthetic corpus in `common_dsp::stems`, once with the stable
+//! default and once with Follow bends. With files, `--note` names the one note each file
+//! plays (for a wrong-note share); without it only note starts and unsure time are reported.
+use common_dsp::parse_note;
+use common_dsp::stems::{self, Score, Truth};
+use common_dsp::tracker::{PitchSource, Scale, TrackerConfig};
+use std::{env, fs, process};
+
+fn row(name: &str, s: Score) {
+    println!(
+        "{name:<14} {:>6.1}s {:>8.2} {:>8.2} {:>7.1}% {:>7.1}%",
+        s.seconds,
+        s.starts,
+        s.extra_starts,
+        s.wrong * 100.,
+        s.unsure * 100.
+    );
+}
+fn header() {
+    println!(
+        "{:<14} {:>7} {:>8} {:>8} {:>8} {:>8}",
+        "stem", "length", "starts/s", "extra/s", "wrong", "unsure"
+    );
+}
+
+fn main() {
+    let mut cfg = TrackerConfig::BASS;
+    let mut source = PitchSource::default();
+    let mut note = None;
+    let mut files = vec![];
+    let mut args = env::args().skip(1);
+    while let Some(a) = args.next() {
+        match a.as_str() {
+            "--sub" => cfg = TrackerConfig::SUB,
+            "--bends" => source.bends = true,
+            "--note" => {
+                let n = args.next().and_then(|n| parse_note(&n));
+                let Some(n) = n else {
+                    eprintln!("--note needs a note name such as F1");
+                    process::exit(2);
+                };
+                note = Some(n);
+                source.note = n;
+            }
+            "--key" => {
+                source.scale = match args.next().as_deref() {
+                    Some("free") => Scale::Free,
+                    Some("minor") => Scale::Minor,
+                    Some("major") => Scale::Major,
+                    Some("root") => Scale::Root,
+                    _ => {
+                        eprintln!("--key needs free, minor, major or root");
+                        process::exit(2);
+                    }
+                };
+            }
+            _ => files.push(a),
+        }
+    }
+    if files.is_empty() {
+        let rate = 48000.;
+        for bends in [false, true] {
+            println!(
+                "\n{}",
+                if bends {
+                    "Follow bends"
+                } else {
+                    "Stable (default)"
+                }
+            );
+            header();
+            let s = PitchSource { bends, ..source };
+            for stem in stems::all(rate) {
+                row(
+                    stem.name,
+                    stems::score(rate, cfg, s, &stem.samples, &stem.truth),
+                );
+            }
+        }
+        return;
+    }
+    header();
+    for path in files {
+        let wave = match fs::read(&path)
+            .map_err(|e| e.to_string())
+            .and_then(|b| common_dsp::wav::decode(&b).map_err(str::to_string))
+        {
+            Ok(w) => w,
+            Err(e) => {
+                eprintln!("{path}: {e}");
+                continue;
+            }
+        };
+        let channels = wave.channels as usize;
+        let mono: Vec<f32> = wave
+            .samples
+            .chunks(channels)
+            .map(|c| c.iter().sum::<f32>() / channels as f32)
+            .collect();
+        // With a known note, quiet samples are skipped rather than counted as silence.
+        let truth = match note {
+            Some(n) => vec![Truth::Note(n as f32); mono.len()],
+            None => vec![],
+        };
+        let name = path.rsplit('/').next().unwrap_or(&path);
+        row(
+            name,
+            stems::score(wave.rate as f32, cfg, source, &mono, &truth),
+        );
+    }
+}

plugins/common/dsp/src/lib.rs

@@ -1,7 +1,9 @@
-//! Shared allocation-free DSP building blocks: filters, pitch detection, notes, WAV files.
+//! Shared allocation-free DSP building blocks: filters, pitch detection, notes, WAV files,
+//! and synthetic test stems.
 pub mod loudness;
 pub mod meter;
 pub mod oversample;
+pub mod stems;
 pub mod svf;
 pub mod tracker;
 pub mod wav;
@@ -221,6 +223,20 @@ pub fn note_name(note: u8) -> String {
     ];
     format!("{}{}", NAMES[note as usize % 12], note as i32 / 12 - 1)
 }
+/// Reads a scientific note name such as "F1" or "c#2", the inverse of [`note_name`].
+pub fn parse_note(text: &str) -> Option<u8> {
+    const NAMES: [&str; 12] = [
+        "C", "C#", "D", "D#", "E", "F", "F#", "G", "G#", "A", "A#", "B",
+    ];
+    let text = text.trim();
+    let split = text.find(|c: char| c.is_ascii_digit() || c == '-')?;
+    let (pitch, octave) = text.split_at(split);
+    let class = NAMES.iter().position(|n| n.eq_ignore_ascii_case(pitch))? as i32;
+    let octave: i32 = octave.parse().ok()?;
+    u8::try_from((octave + 1) * 12 + class)
+        .ok()
+        .filter(|n| *n <= 127)
+}
 pub fn db_to_gain(db: f32) -> f32 {
     10f32.powf(db / 20.)
 }

plugins/common/dsp/src/stems.rs

@@ -0,0 +1,414 @@
+//! Synthetic bass stems with known notes, and a score for how well the tracker follows them.
+//!
+//! The stems imitate what makes real bass hard to track: FM growls, detuned reeses, moving
+//! formants over a weak fundamental, 808 slides, layered octaves and noise. They are a stand-in
+//! until real stems are collected; `examples/tracker_report.rs` scores real WAV files too.
+use crate::tracker::{NoteEvent, PitchSource, Tracker, TrackerConfig};
+use crate::{midi_to_hz, Biquad, Saw};
+use std::f32::consts::TAU;
+
+/// What the tracker should report for one input sample.
+#[derive(Clone, Copy, Debug, PartialEq)]
+pub enum Truth {
+    /// One note sounds at this fractional MIDI pitch.
+    Note(f32),
+    /// No note sounds; reporting one is wrong.
+    Silent,
+    /// A transition (attack, slide): not scored.
+    Skip,
+}
+
+pub struct Stem {
+    pub name: &'static str,
+    pub samples: Vec<f32>,
+    pub truth: Vec<Truth>,
+}
+
+/// Deterministic white noise in -1..1.
+struct Noise(u32);
+impl Noise {
+    fn sample(&mut self) -> f32 {
+        self.0 ^= self.0 << 13;
+        self.0 ^= self.0 >> 17;
+        self.0 ^= self.0 << 5;
+        self.0 as f32 / u32::MAX as f32 * 2. - 1.
+    }
+}
+
+/// Notes as (start s, end s, MIDI note). Samples outside every note are silent; the first
+/// `SKIP_S` of each note is not scored.
+const SKIP_S: f32 = 0.03;
+fn truth(rate: f32, len: usize, notes: &[(f32, f32, f32)]) -> Vec<Truth> {
+    (0..len)
+        .map(|i| {
+            let t = i as f32 / rate;
+            match notes.iter().find(|(a, b, _)| t >= *a && t < *b) {
+                Some((a, _, n)) if t - a >= SKIP_S => Truth::Note(*n),
+                Some(_) => Truth::Skip,
+                None => Truth::Silent,
+            }
+        })
+        .collect()
+}
+/// Short fade at note edges so onsets are clean.
+fn envelope(t: f32, a: f32, b: f32) -> f32 {
+    ((t - a) / 0.005).clamp(0., 1.) * ((b - t) / 0.005).clamp(0., 1.)
+}
+
+fn growl(rate: f32) -> Stem {
+    // FM: modulator at twice the carrier, index wobbling at 3 Hz, then driven.
+    let notes = [(0.1, 1.9, 29.), (2.0, 3.9, 32.)];
+    let len = (4. * rate) as usize;
+    let (mut pc, mut pm) = (0f32, 0f32);
+    let samples = (0..len)
+        .map(|i| {
+            let t = i as f32 / rate;
+            let Some(&(a, b, n)) = notes.iter().find(|(a, b, _)| t >= *a && t < *b) else {
+                return 0.;
+            };
+            let hz = midi_to_hz(n);
+            pc = (pc + hz / rate).fract();
+            pm = (pm + 2. * hz / rate).fract();
+            let index = 3. + 3. * (TAU * 3. * t).sin();
+            let x = (TAU * pc + index * (TAU * pm).sin()).sin();
+            0.5 * (2.5 * x).tanh() * envelope(t, a, b)
+        })
+        .collect();
+    Stem {
+        name: "growl",
+        samples,
+        truth: truth(rate, len, &notes),
+    }
+}
+
+fn hard_growl(rate: f32) -> Stem {
+    // FM at a 1:1 ratio, index sweeping 2–12 at 6 Hz, hard drive, then a sweeping resonance.
+    let notes = [(0.1, 1.0, 31.), (1.0, 2.0, 34.), (2.1, 3.9, 29.)];
+    let len = (4. * rate) as usize;
+    let (mut pc, mut pm) = (0f32, 0f32);
+    let mut band = Biquad::default();
+    let samples = (0..len)
+        .map(|i| {
+            let t = i as f32 / rate;
+            let Some(&(a, b, n)) = notes.iter().find(|(a, b, _)| t >= *a && t < *b) else {
+                return 0.;
+            };
+            if i % 32 == 0 {
+                let sweep = 0.5 + 0.5 * (TAU * 6. * t).sin();
+                band = retuned(band, Biquad::peak(rate, 200. + 1800. * sweep, 3., 12.));
+            }
+            let hz = midi_to_hz(n);
+            pc = (pc + hz / rate).fract();
+            pm = (pm + hz / rate).fract();
+            let index = 7. + 5. * (TAU * 6. * t).sin();
+            let x = (4. * (TAU * pc + index * (TAU * pm).sin()).sin()).tanh();
+            0.15 * band.process(x) * envelope(t, a, b)
+        })
+        .collect();
+    Stem {
+        name: "hard growl",
+        samples,
+        truth: truth(rate, len, &notes),
+    }
+}
+
+fn wobble(rate: f32) -> Stem {
+    // A saw on G1 through a resonant low-pass wobbling 80–1500 Hz at 1/8 notes of 140 BPM.
+    let notes = [(0.1, 3.9, 31.)];
+    let len = (4. * rate) as usize;
+    let mut saw = Saw::new(rate, midi_to_hz(31.));
+    let mut lp = [Biquad::default(); 2];
+    let samples = (0..len)
+        .map(|i| {
+            let t = i as f32 / rate;
+            let (a, b, _) = notes[0];
+            if t < a || t >= b {
+                return 0.;
+            }
+            if i % 32 == 0 {
+                let lfo = 0.5 - 0.5 * (TAU * (140. / 60. * 2.) * t).cos();
+                let hz = 80. * (1500f32 / 80.).powf(lfo);
+                lp[0] = retuned(lp[0], Biquad::lowpass(rate, hz, 6.));
+                lp[1] = retuned(lp[1], Biquad::lowpass(rate, hz, 0.7));
+            }
+            let y = lp[0].process(0.3 * saw.sample());
+            lp[1].process(y) * envelope(t, a, b)
+        })
+        .collect();
+    Stem {
+        name: "wobble",
+        samples,
+        truth: truth(rate, len, &notes),
+    }
+}
+
+fn reese(rate: f32) -> Stem {
+    // Two saws 12 cents apart, lowpassed; A1 then D2 legato.
+    let notes = [(0.1, 2.0, 33.), (2.0, 3.9, 38.)];
+    let len = (4. * rate) as usize;
+    let mut lp = [Biquad::lowpass(rate, 900., 0.7); 2];
+    let mut saws: Option<(f32, Saw, Saw)> = None;
+    let samples = (0..len)
+        .map(|i| {
+            let t = i as f32 / rate;
+            let Some(&(_, _, n)) = notes.iter().find(|(a, b, _)| t >= *a && t < *b) else {
+                return 0.;
+            };
+            if saws.as_ref().map(|s| s.0) != Some(n) {
+                let hz = midi_to_hz(n);
+                saws = Some((
+                    n,
+                    Saw::new(rate, hz * 2f32.powf(0.06 / 12.)),
+                    Saw::new(rate, hz * 2f32.powf(-0.06 / 12.)),
+                ));
+            }
+            let (_, a, b) = saws.as_mut().unwrap();
+            let x = 0.3 * (a.sample() + b.sample());
+            let y = lp[0].process(x);
+            let y = lp[1].process(y);
+            y * envelope(t, notes[0].0, notes[1].1)
+        })
+        .collect();
+    Stem {
+        name: "reese",
+        samples,
+        truth: truth(rate, len, &notes),
+    }
+}
+
+fn formant(rate: f32) -> Stem {
+    // A saw on E1 through two sweeping band-passes; the fundamental is 18 dB down.
+    let notes = [(0.1, 3.9, 28.)];
+    let len = (4. * rate) as usize;
+    let hz = midi_to_hz(28.);
+    let mut saw = Saw::new(rate, hz);
+    let mut phase = 0f32;
+    let mut bands = [Biquad::default(); 2];
+    let samples = (0..len)
+        .map(|i| {
+            let t = i as f32 / rate;
+            let (a, b, _) = notes[0];
+            if t < a || t >= b {
+                return 0.;
+            }
+            if i % 32 == 0 {
+                let sweep = 0.5 + 0.5 * (TAU * 1.5 * t).sin();
+                bands[0] = retuned(bands[0], Biquad::peak(rate, 300. + 500. * sweep, 4., 18.));
+                bands[1] = retuned(bands[1], Biquad::peak(rate, 900. + 900. * sweep, 4., 18.));
+            }
+            phase = (phase + hz / rate).fract();
+            let x = 0.05 * saw.sample();
+            let y = bands[0].process(x);
+            let y = bands[1].process(y);
+            (0.4 * y + 0.06 * (TAU * phase).sin()) * envelope(t, a, b)
+        })
+        .collect();
+    Stem {
+        name: "formant",
+        samples,
+        truth: truth(rate, len, &notes),
+    }
+}
+fn retuned(mut old: Biquad, new: Biquad) -> Biquad {
+    old.retune(new);
+    old
+}
+
+fn slide808(rate: f32) -> Stem {
+    // A saturated sine on C2 that slides down to G1 over 60 ms, decaying slowly.
+    let notes = [(0.1, 1.0, 36.), (1.0, 3.0, 31.)];
+    let len = (3.2 * rate) as usize;
+    let mut phase = 0f32;
+    let samples = (0..len)
+        .map(|i| {
+            let t = i as f32 / rate;
+            if !(0.1..3.0).contains(&t) {
+                return 0.;
+            }
+            let n = if t < 1. {
+                36.
+            } else {
+                36. - 5. * ((t - 1.) / 0.06).min(1.)
+            };
+            phase = (phase + midi_to_hz(n) / rate).fract();
+            let decay = (-(t - 0.1) / 2.5).exp();
+            0.6 * decay * (2. * (TAU * phase).sin()).tanh() * envelope(t, 0.1, 3.)
+        })
+        .collect();
+    let mut truth = truth(rate, len, &notes);
+    // The slide itself is not scored.
+    for (i, v) in truth.iter_mut().enumerate() {
+        let t = i as f32 / rate;
+        if (1.0..1.1).contains(&t) {
+            *v = Truth::Skip;
+        }
+    }
+    Stem {
+        name: "808 slide",
+        samples,
+        truth,
+    }
+}
+
+fn layered(rate: f32) -> Stem {
+    // Sub sine on F1 under an FM growl an octave up, plus noise: the drop's low end.
+    let notes = [(0.1, 3.9, 29.)];
+    let len = (4. * rate) as usize;
+    let hz = midi_to_hz(29.);
+    let (mut sub, mut pc, mut pm) = (0f32, 0f32, 0f32);
+    let mut noise = Noise(0x9e37_79b9);
+    let samples = (0..len)
+        .map(|i| {
+            let t = i as f32 / rate;
+            let (a, b, _) = notes[0];
+            if t < a || t >= b {
+                return 0.;
+            }
+            sub = (sub + hz / rate).fract();
+            pc = (pc + 2. * hz / rate).fract();
+            pm = (pm + 3. * hz / rate).fract();
+            let index = 2. + 2. * (TAU * 2. * t).sin();
+            let growl = (2. * (TAU * pc + index * (TAU * pm).sin()).sin()).tanh();
+            (0.3 * (TAU * sub).sin() + 0.35 * growl + 0.05 * noise.sample()) * envelope(t, a, b)
+        })
+        .collect();
+    Stem {
+        name: "layered",
+        samples,
+        truth: truth(rate, len, &notes),
+    }
+}
+
+fn riser(rate: f32) -> Stem {
+    // Low-passed noise swelling up: no note at all.
+    let len = (3. * rate) as usize;
+    let mut noise = Noise(0x1234_5678);
+    let mut lp = [Biquad::lowpass(rate, 600., 0.7); 2];
+    let samples = (0..len)
+        .map(|i| {
+            let t = i as f32 / rate;
+            let x = noise.sample() * 0.6 * (t / 3.);
+            let y = lp[0].process(x);
+            lp[1].process(y)
+        })
+        .collect();
+    Stem {
+        name: "noise riser",
+        samples,
+        truth: vec![Truth::Silent; len],
+    }
+}
+
+/// The corpus at sample rate `rate`.
+pub fn all(rate: f32) -> Vec<Stem> {
+    vec![
+        growl(rate),
+        hard_growl(rate),
+        wobble(rate),
+        reese(rate),
+        formant(rate),
+        slide808(rate),
+        layered(rate),
+        riser(rate),
+    ]
+}
+
+/// How the tracker did on one stem. Shares are of the scored samples.
+#[derive(Clone, Copy, Debug, Default, PartialEq)]
+pub struct Score {
+    pub seconds: f32,
+    /// Note starts per second beyond the stem's real notes (0 when no truth is known).
+    pub extra_starts: f32,
+    /// Note starts per second.
+    pub starts: f32,
+    /// Share of note samples where the tracker reports a sure note that is wrong by more
+    /// than half a semitone, plus silent samples where it reports a sure note.
+    pub wrong: f32,
+    /// Share of note samples where the tracker is unsure or reports no note.
+    pub unsure: f32,
+}
+
+/// Runs `samples` through a tracker and scores its output against `truth` (input-aligned;
+/// empty when unknown).
+pub fn score(
+    rate: f32,
+    cfg: TrackerConfig,
+    source: PitchSource,
+    samples: &[f32],
+    truth: &[Truth],
+) -> Score {
+    let mut t = Tracker::new(rate, cfg);
+    t.set(source);
+    let latency = t.latency();
+    let mut pitch = 0f32;
+    let mut starts = 0usize;
+    let (mut wrong, mut unsure, mut scored) = (0usize, 0usize, 0usize);
+    for i in 0..samples.len() + latency {
+        let x = samples.get(i).copied().unwrap_or(0.);
+        t.process(x, |e| match e {
+            NoteEvent::Start { pitch: p, .. } => {
+                pitch = p;
+                starts += 1;
+            }
+            NoteEvent::Move { pitch: p } => pitch = p,
+            NoteEvent::Stop => {}
+        });
+        let Some(at) = i.checked_sub(latency) else {
+            continue;
+        };
+        let sure = t.active();
+        match truth.get(at) {
+            Some(Truth::Note(n)) => {
+                scored += 1;
+                if !sure {
+                    unsure += 1;
+                } else if (pitch - n).abs() > 0.5 {
+                    wrong += 1;
+                }
+            }
+            Some(Truth::Silent) => {
+                scored += 1;
+                if sure {
+                    wrong += 1;
+                }
+            }
+            _ => {}
+        }
+    }
+    let seconds = samples.len() as f32 / rate;
+    let notes = count_notes(truth);
+    let share = |n: usize| {
+        if scored > 0 {
+            n as f32 / scored as f32
+        } else {
+            0.
+        }
+    };
+    Score {
+        seconds,
+        extra_starts: if truth.is_empty() {
+            0.
+        } else {
+            starts.saturating_sub(notes) as f32 / seconds
+        },
+        starts: starts as f32 / seconds,
+        wrong: share(wrong),
+        unsure: share(unsure),
+    }
+}
+/// Number of distinct notes in a truth track (a slide counts as a new note).
+fn count_notes(truth: &[Truth]) -> usize {
+    let mut last = None;
+    let mut n = 0;
+    for v in truth {
+        match v {
+            Truth::Note(p) if last != Some(*p) => {
+                n += 1;
+                last = Some(*p);
+            }
+            Truth::Silent => last = None,
+            _ => {}
+        }
+    }
+    n
+}

plugins/common/dsp/src/tracker.rs

@@ -3,7 +3,14 @@
 //! Detection runs on the undelayed input. Events are reported at *output* time, `latency()`
 //! samples later, so a host that delays its audio path by the same amount sees each note start
 //! exactly on its attack, with the pitch already known.
-use crate::{coefficient, gain_to_db, hz_to_midi, Biquad, Yin};
+//!
+//! Detection is built to stay put. A new note needs a confident pitch held for `NOTE_MS`
+//! (`OCTAVE_MS` for an octave jump), and inside a note the tuning only moves when the pitch
+//! drifts past `DEADBAND` for good. When the pitch reads keep disagreeing (FM growls, noise,
+//! formant sweeps), the tracker reports itself unsure: [`Tracker::active`] turns false, and
+//! tracked processing should fall back to something neutral rather than act on a guess.
+use crate::{coefficient, db_to_gain, gain_to_db, hz_to_midi, Biquad, Yin};
+use serde::{Deserialize, Serialize};
 
 const EVENTS: usize = 64;
 const HOP_MS: f32 = 5.;
@@ -12,6 +19,162 @@ const GATE_HYSTERESIS_DB: f32 = 6.;
 /// A pitch move this large (semitones) counts as a new note.
 const JUMP: f32 = 0.7;
 const CLARITY: f32 = 0.5;
+/// A different pitch must hold this long before it becomes the new note.
+const NOTE_MS: f32 = 40.;
+/// A jump down an octave must hold this long: octave errors are the commonest misread.
+const OCTAVE_MS: f32 = 80.;
+/// A jump up an octave must hold this long. A signal one octave up still repeats at the
+/// note's period, and detuned or FM basses read an octave up whenever their odd harmonics
+/// cancel, so these reads count as agreeing with the note.
+const OCTAVE_UP_MS: f32 = 200.;
+/// A new note's reads must stay within this spread (semitones): a swept resonance drags the
+/// reads along continuously, a real note change settles.
+const STEADY: f32 = 0.5;
+/// A note ends when the start of the analysis window (output time) stays this long below the
+/// gate's release level. Faster than the gate, whose envelope needs over 100 ms to fall.
+const QUIET_MS: f32 = 20.;
+/// Inside a note, the tuning moves only when the settled pitch is this far (semitones) off.
+const DEADBAND: f32 = 0.25;
+/// Per-hop step of the settled pitch towards each agreeing read.
+const SETTLE: f32 = 0.2;
+/// Trust kept per disagreeing read: about 40 ms of them make the note unsure.
+const TRUST_DISAGREE: f32 = 0.85;
+/// Trust kept per hop with no read: about 400 ms without one make the note unsure. Growls
+/// read only now and then, between stretches YIN cannot read at all.
+const TRUST_SILENT: f32 = 0.985;
+/// Share of the missing trust one agreeing read restores.
+const TRUST_AGREE: f32 = 0.5;
+const TRUST_LOST: f32 = 0.3;
+const TRUST_REGAINED: f32 = 0.6;
+
+/// Where notes come from.
+#[derive(Clone, Copy, Debug, PartialEq, Eq, Default)]
+pub enum PitchMode {
+    /// Pitch and note starts are detected from the audio.
+    #[default]
+    Audio,
+    /// Notes come from MIDI note input.
+    Midi,
+    /// Note starts come from the audio, the pitch is the fixed `note`: no detection at all.
+    Note,
+}
+
+/// Key lock for detected pitches. The root is the pitch class of [`PitchSource::note`].
+#[derive(Clone, Copy, Debug, PartialEq, Eq, Default, Serialize, Deserialize)]
+#[serde(rename_all = "lowercase")]
+pub enum Scale {
+    /// Any pitch, including between notes.
+    #[default]
+    Free,
+    /// Natural minor.
+    Minor,
+    Major,
+    /// Only the root, in any octave: detection picks the octave.
+    Root,
+}
+impl Scale {
+    fn steps(self) -> &'static [i32] {
+        match self {
+            Scale::Free => &[],
+            Scale::Minor => &[0, 2, 3, 5, 7, 8, 10],
+            Scale::Major => &[0, 2, 4, 5, 7, 9, 11],
+            Scale::Root => &[0],
+        }
+    }
+    /// The in-key note nearest `pitch`, or `pitch` itself when the scale is free.
+    pub fn snap(self, root: u8, pitch: f32) -> f32 {
+        let steps = self.steps();
+        if steps.is_empty() {
+            return pitch;
+        }
+        let root = (root % 12) as i32;
+        let base = pitch.round() as i32;
+        let mut best = base as f32;
+        let mut distance = f32::MAX;
+        for n in base - 7..=base + 7 {
+            if steps.contains(&(n - root).rem_euclid(12)) {
+                let d = (n as f32 - pitch).abs();
+                if d < distance {
+                    distance = d;
+                    best = n as f32;
+                }
+            }
+        }
+        best
+    }
+}
+
+/// The user's pitch-source choices, shared by every tracked plugin.
+#[derive(Clone, Copy, Debug, PartialEq)]
+pub struct PitchSource {
+    pub mode: PitchMode,
+    /// Detection threshold in dBFS for note starts (Audio and Note modes).
+    pub gate_db: f32,
+    /// Legato notes slide instead of restarting.
+    pub glide: bool,
+    /// The note played in Note mode (MIDI number); its pitch class is the key root.
+    pub note: u8,
+    pub scale: Scale,
+    /// Follow bends and vibrato on every hop and switch notes after 10 ms, as before 2026-11.
+    /// Fast, but it flickers on growls.
+    pub bends: bool,
+}
+impl Default for PitchSource {
+    fn default() -> Self {
+        Self {
+            mode: PitchMode::Audio,
+            gate_db: -42.,
+            glide: false,
+            note: DEFAULT_NOTE,
+            scale: Scale::Free,
+            bends: false,
+        }
+    }
+}
+/// F1, the commonest riddim root.
+pub const DEFAULT_NOTE: u8 = 29;
+/// Range of the Note control: C0 to C5.
+pub const NOTE_MIN: u8 = 12;
+pub const NOTE_MAX: u8 = 72;
+
+/// The stored part of a plugin's pitch source beside its mode and gate: Note mode's note, the
+/// key lock and Follow bends. Plugins keep it as one `pitch` field in their settings.
+#[derive(Clone, Copy, Debug, PartialEq, Eq, Serialize, Deserialize)]
+#[serde(deny_unknown_fields, default)]
+pub struct Pitch {
+    pub note: u8,
+    pub scale: Scale,
+    pub bends: bool,
+}
+impl Default for Pitch {
+    fn default() -> Self {
+        Self {
+            note: DEFAULT_NOTE,
+            scale: Scale::Free,
+            bends: false,
+        }
+    }
+}
+impl Pitch {
+    pub fn validate(&self) -> Result<(), &'static str> {
+        if (NOTE_MIN..=NOTE_MAX).contains(&self.note) {
+            Ok(())
+        } else {
+            Err("Note out of range")
+        }
+    }
+    /// The full tracker settings for `mode`, a gate threshold in dBFS and legato slides.
+    pub fn source(self, mode: PitchMode, gate_db: f32, glide: bool) -> PitchSource {
+        PitchSource {
+            mode,
+            gate_db,
+            glide,
+            note: self.note,
+            scale: self.scale,
+            bends: self.bends,
+        }
+    }
+}
 
 #[derive(Clone, Copy, Debug, PartialEq)]
 pub struct TrackerConfig {
@@ -40,6 +203,40 @@ impl TrackerConfig {
     };
 }
 
+/// The tracker's note state at one output sample.
+#[derive(Clone, Copy, Debug, Default, PartialEq, Eq)]
+pub struct NoteState {
+    /// A note sounds.
+    pub sounding: bool,
+    /// The sounding note's pitch is trusted ([`Tracker::active`]); false while none sounds.
+    pub sure: bool,
+}
+impl NoteState {
+    /// A note sounds but its pitch is not trusted: tracked processing should step back.
+    pub fn unsure(self) -> bool {
+        self.sounding && !self.sure
+    }
+}
+
+/// Latches "step back" across note ends: a module goes neutral while its note is unsure and
+/// returns only on a sure note, so a tail after an unsure stretch stays neutral too.
+#[derive(Clone, Copy, Debug, Default)]
+pub struct Fallback {
+    neutral: bool,
+}
+impl Fallback {
+    /// Updates from this sample's note state; true while the module should sound neutral.
+    pub fn neutral(&mut self, note: NoteState) -> bool {
+        if note.sounding {
+            self.neutral = !note.sure;
+        }
+        self.neutral
+    }
+    pub fn reset(&mut self) {
+        self.neutral = false;
+    }
+}
+
 #[derive(Clone, Copy, Debug, PartialEq)]
 pub enum NoteEvent {
     /// A new note. `glide` asks to slide from the previous pitch instead of restarting.
@@ -67,14 +264,50 @@ struct Event {
     kind: Kind,
 }
 
+/// A pitch that may become the next note.
+#[derive(Clone, Copy, Debug)]
+struct Candidate {
+    mean: f32,
+    low: f32,
+    high: f32,
+    reads: u32,
+}
+impl Candidate {
+    fn new(p: f32) -> Self {
+        Self {
+            mean: p,
+            low: p,
+            high: p,
+            reads: 1,
+        }
+    }
+    /// Adds a read, or returns None when it does not fit this candidate.
+    fn add(self, p: f32) -> Option<Self> {
+        let (low, high) = (self.low.min(p), self.high.max(p));
+        (high - low < STEADY).then(|| Self {
+            mean: self.mean + (p - self.mean) / (self.reads + 1) as f32,
+            low,
+            high,
+            reads: self.reads + 1,
+        })
+    }
+}
+
+/// One analysis window's result.
+#[derive(Clone, Copy, Debug)]
+enum Read {
+    Pitch(f32),
+    /// Sound YIN cannot read: no evidence either way.
+    Unclear,
+    Silent,
+}
+
 /// Allocation-free after `new`. Pitches are fractional MIDI notes.
 pub struct Tracker {
     rate: f32,
     cfg: TrackerConfig,
     latency: usize,
-    midi: bool,
-    gate_db: f32,
-    glide: bool,
+    source: PitchSource,
     detect: [Biquad; 2],
     decimate: usize,
     decimate_count: usize,
@@ -85,6 +318,9 @@ pub struct Tracker {
     yin: Yin,
     hop: usize,
     hop_count: usize,
+    note_hops: u32,
+    octave_hops: u32,
+    octave_up_hops: u32,
     gate_env: f32,
     gate_release: f32,
     gate_open: bool,
@@ -96,8 +332,17 @@ pub struct Tracker {
     /// Output-time note state.
     sounding: bool,
     pending: bool,
+    /// The note ended on silence while the gate stayed open: the next sound starts a note.
+    rest: bool,
+    quiet_hops: u32,
+    quiet_need: u32,
     tracked: f32,
-    candidate: Option<(f32, u8)>,
+    /// Running pitch of the agreeing reads inside the note.
+    settled: f32,
+    candidate: Option<Candidate>,
+    /// 1 while reads agree with the note, falling towards 0 while they do not.
+    trust: f32,
+    sure: bool,
     held: [u8; 16],
     held_len: usize,
 }
@@ -110,13 +355,13 @@ impl Tracker {
         // YIN needs one comparison window of at least the longest period after the lags.
         let analysis = 2 * max_lag + 3;
         let q = std::f32::consts::FRAC_1_SQRT_2;
+        let hop = ((detect_rate * HOP_MS * 0.001) as usize).max(1);
+        let hop_ms = hop as f32 / detect_rate * 1000.;
         Self {
             rate,
             cfg,
             latency: analysis * decimate,
-            midi: false,
-            gate_db: -42.,
-            glide: false,
+            source: PitchSource::default(),
             detect: [Biquad::lowpass(rate, cfg.detect_lowpass, q); 2],
             decimate,
             decimate_count: 0,
@@ -125,8 +370,11 @@ impl Tracker {
             ring_at: 0,
             scratch: vec![0.; analysis],
             yin: Yin::new(max_lag + 2),
-            hop: ((detect_rate * HOP_MS * 0.001) as usize).max(1),
+            hop,
             hop_count: 0,
+            note_hops: (NOTE_MS / hop_ms).round().max(2.) as u32,
+            octave_hops: (OCTAVE_MS / hop_ms).round().max(2.) as u32,
+            octave_up_hops: (OCTAVE_UP_MS / hop_ms).round().max(2.) as u32,
             gate_env: 0.,
             gate_release: 1. - coefficient(rate, 30.),
             gate_open: false,
@@ -140,8 +388,14 @@ impl Tracker {
             event_len: 0,
             sounding: false,
             pending: false,
+            rest: false,
+            quiet_hops: 0,
+            quiet_need: (QUIET_MS / hop_ms).round().max(1.) as u32,
             tracked: 0.,
+            settled: 0.,
             candidate: None,
+            trust: 0.,
+            sure: false,
             held: [0; 16],
             held_len: 0,
         }
@@ -153,22 +407,28 @@ impl Tracker {
     pub fn config(&self) -> TrackerConfig {
         self.cfg
     }
-    /// `midi` selects note input over detection; `gate_db` is the detection threshold;
-    /// `glide` lets legato notes slide. Returns true when the source changed, which drops
-    /// every pending and held note: the caller should release its sound.
-    pub fn set(&mut self, midi: bool, gate_db: f32, glide: bool) -> bool {
-        let changed = midi != self.midi;
-        self.midi = midi;
-        self.gate_db = gate_db;
-        self.glide = glide;
+    pub fn source(&self) -> PitchSource {
+        self.source
+    }
+    /// Applies the pitch-source choices. Returns true when the mode changed, which drops every
+    /// pending and held note: the caller should release its sound.
+    pub fn set(&mut self, source: PitchSource) -> bool {
+        let changed = source.mode != self.source.mode;
+        self.source = source;
         if changed {
             self.release_all();
         }
         changed
     }
+    fn midi(&self) -> bool {
+        self.source.mode == PitchMode::Midi
+    }
     fn release_all(&mut self) {
         self.sounding = false;
         self.pending = false;
+        self.rest = false;
+        self.quiet_hops = 0;
+        self.sure = false;
         self.held_len = 0;
         self.event_len = 0;
         self.candidate = None;
@@ -192,10 +452,22 @@ impl Tracker {
     pub fn note_off(&mut self, note: u8) {
         self.push(Kind::NoteOff(note.min(127)));
     }
-    /// True while a note sounds at output time.
+    /// True while a note sounds at output time, sure or not.
     pub fn sounding(&self) -> bool {
         self.sounding
     }
+    /// True while tracked processing should act: a note sounds and its pitch is trusted.
+    /// MIDI and Note modes are always sure; detection is unsure from an onset until a pitch
+    /// reads, and while reads keep disagreeing with the note.
+    pub fn active(&self) -> bool {
+        self.sounding && (self.source.mode != PitchMode::Audio || self.sure)
+    }
+    pub fn state(&self) -> NoteState {
+        NoteState {
+            sounding: self.sounding,
+            sure: self.active(),
+        }
+    }
     fn push(&mut self, kind: Kind) {
         if self.event_len == EVENTS {
             // Dropping the oldest keeps the newest note state; overflow only happens on floods.
@@ -209,45 +481,81 @@ impl Tracker {
         };
         self.event_len += 1;
     }
-    /// Detected pitch of the most recent analysis window, in fractional MIDI notes.
-    fn estimate(&mut self) -> Option<f32> {
+    /// Detected pitch of the most recent analysis window, in fractional MIDI notes, snapped to
+    /// the key when one is set.
+    fn estimate(&mut self) -> Read {
         let n = self.ring.len();
         for i in 0..n {
             self.scratch[i] = self.ring[(self.ring_at + i) % n];
         }
-        let (hz, clarity) = self.yin.estimate(
+        // The window starts at output time: a quiet head means the note has ended there.
+        let head = self.hop.min(n);
+        let power = self.scratch[..head].iter().map(|v| v * v).sum::<f32>() / head as f32;
+        let quiet = db_to_gain(self.source.gate_db - GATE_HYSTERESIS_DB);
+        if power < quiet * quiet {
+            return Read::Silent;
+        }
+        let s = self.source;
+        match self.yin.estimate(
             &self.scratch,
             self.detect_rate,
             self.cfg.min_hz,
             self.cfg.max_hz,
-        )?;
-        (clarity >= CLARITY).then(|| hz_to_midi(hz))
+        ) {
+            Some((hz, clarity)) if clarity >= CLARITY => {
+                Read::Pitch(s.scale.snap(s.note, hz_to_midi(hz)))
+            }
+            _ => Read::Unclear,
+        }
     }
     fn start(&mut self, pitch: f32, glide: bool, emit: &mut impl FnMut(NoteEvent)) {
         self.tracked = pitch;
+        self.settled = pitch;
         self.candidate = None;
         self.pending = false;
         self.sounding = true;
+        self.trust = 1.;
+        self.sure = true;
         emit(NoteEvent::Start { pitch, glide });
     }
     fn stop(&mut self, emit: &mut impl FnMut(NoteEvent)) {
+        let was = self.sounding || self.pending;
         self.sounding = false;
         self.pending = false;
+        self.sure = false;
+        self.quiet_hops = 0;
         self.candidate = None;
-        emit(NoteEvent::Stop);
+        if was {
+            emit(NoteEvent::Stop);
+        }
+    }
+    /// A note starts at output time from `read`: detected (or pending until a pitch reads) in
+    /// Audio mode, the set note in Note mode.
+    fn onset(&mut self, read: Read, emit: &mut impl FnMut(NoteEvent)) {
+        self.rest = false;
+        self.quiet_hops = 0;
+        match (self.source.mode, read) {
+            (PitchMode::Note, _) => self.start(self.source.note as f32, false, emit),
+            (_, Read::Pitch(p)) => self.start(p, false, emit),
+            _ => {
+                self.pending = true;
+                self.sounding = true;
+                self.sure = false;
+                self.trust = 0.;
+            }
+        }
     }
     fn handle(&mut self, kind: Kind, emit: &mut impl FnMut(NoteEvent)) {
-        let midi = self.midi;
-        match kind {
-            Kind::Onset if !midi => match self.estimate() {
-                Some(p) => self.start(p, false, emit),
-                None => {
-                    self.pending = true;
-                    self.sounding = true;
-                }
-            },
-            Kind::Release if !midi => self.stop(emit),
-            Kind::NoteOn(n) if midi => {
+        match (self.source.mode, kind) {
+            (PitchMode::Audio | PitchMode::Note, Kind::Onset) => {
+                let read = self.estimate();
+                self.onset(read, emit);
+            }
+            (PitchMode::Audio | PitchMode::Note, Kind::Release) => {
+                self.rest = false;
+                self.stop(emit);
+            }
+            (PitchMode::Midi, Kind::NoteOn(n)) => {
                 let len = self.held_len;
                 if let Some(i) = self.held[..len].iter().position(|h| *h == n) {
                     self.held.copy_within(i + 1..len, i);
@@ -260,9 +568,9 @@ impl Tracker {
                 let legato = self.held_len > 0;
                 self.held[self.held_len] = n;
                 self.held_len += 1;
-                self.start(n as f32, legato && self.glide, emit);
+                self.start(n as f32, legato && self.source.glide, emit);
             }
-            Kind::NoteOff(n) if midi => {
+            (PitchMode::Midi, Kind::NoteOff(n)) => {
                 let len = self.held_len;
                 let Some(i) = self.held[..len].iter().position(|h| *h == n) else {
                     return;
@@ -274,48 +582,119 @@ impl Tracker {
                     self.stop(emit);
                 } else if top {
                     let next = self.held[self.held_len - 1];
-                    self.start(next as f32, self.glide, emit);
+                    self.start(next as f32, self.source.glide, emit);
                 }
             }
             _ => {}
         }
     }
+    /// Moves the trust score one hop: `Some(true)` for a read that agrees with the note,
+    /// `Some(false)` for one that does not, `None` for no read. Hysteresis on `sure`.
+    fn trust(&mut self, agree: Option<bool>) {
+        match agree {
+            Some(true) => self.trust += (1. - self.trust) * TRUST_AGREE,
+            Some(false) => self.trust *= TRUST_DISAGREE,
+            None => self.trust *= TRUST_SILENT,
+        }
+        if self.sure && self.trust < TRUST_LOST {
+            self.sure = false;
+        } else if !self.sure && self.trust > TRUST_REGAINED {
+            self.sure = true;
+        }
+    }
     /// Regular analysis; its window starts at the current output time.
     fn hop_analysis(&mut self, emit: &mut impl FnMut(NoteEvent)) {
-        if self.midi || !self.sounding {
+        if self.midi() || !(self.sounding || self.rest) {
             return;
         }
-        let Some(p) = self.estimate() else {
-            return;
-        };
-        if self.pending {
-            self.start(p, false, emit);
-            return;
-        }
-        if (p - self.tracked).abs() >= JUMP {
-            match self.candidate {
-                Some((c, count)) if (c - p).abs() < 0.5 => {
-                    if count + 1 >= 2 {
-                        self.start(p, self.glide, emit);
-                    } else {
-                        self.candidate = Some((p, count + 1));
-                    }
+        let read = self.estimate();
+        if let Read::Silent = read {
+            if self.sounding && !self.pending {
+                self.quiet_hops += 1;
+                if self.quiet_hops >= self.quiet_need {
+                    self.stop(emit);
+                    self.rest = true;
+                } else {
+                    self.trust(Some(false));
                 }
-                _ => self.candidate = Some((p, 1)),
+            }
+            return;
+        }
+        self.quiet_hops = 0;
+        if self.rest {
+            return self.onset(read, emit);
+        }
+        if self.source.mode == PitchMode::Note {
+            return;
+        }
+        if self.pending {
+            if let Read::Pitch(p) = read {
+                self.start(p, false, emit);
+            }
+            return;
+        }
+        let p = match read {
+            Read::Pitch(p) => p,
+            Read::Unclear => return self.trust(None),
+            Read::Silent => unreachable!(),
+        };
+        let offset = p - self.tracked;
+        if offset.abs() < JUMP {
+            self.candidate = None;
+            self.trust(Some(true));
+            if self.source.bends {
+                self.tracked += 0.3 * offset;
+                emit(NoteEvent::Move {
+                    pitch: self.tracked,
+                });
+            } else {
+                self.settled += SETTLE * (p - self.settled);
+                if (self.settled - self.tracked).abs() >= DEADBAND {
+                    self.tracked = self.settled;
+                    emit(NoteEvent::Move {
+                        pitch: self.tracked,
+                    });
+                }
+            }
+            return;
+        }
+        let octaves = (offset / 12.).round();
+        let octave = octaves != 0. && (offset - 12. * octaves).abs() < JUMP;
+        let up = octave && octaves > 0.;
+        let candidate = if self.source.bends {
+            // The 0.1 rule: two reads within half a semitone.
+            match self.candidate {
+                Some(c) if (c.mean - p).abs() < 0.5 => Candidate {
+                    mean: p,
+                    reads: c.reads + 1,
+                    ..c
+                },
+                _ => Candidate::new(p),
             }
         } else {
-            self.candidate = None;
-            self.tracked += 0.3 * (p - self.tracked);
-            emit(NoteEvent::Move {
-                pitch: self.tracked,
-            });
+            self.candidate
+                .and_then(|c| c.add(p))
+                .unwrap_or(Candidate::new(p))
+        };
+        let need = match (self.source.bends, octave, up) {
+            (true, _, _) => 2,
+            (false, false, _) => self.note_hops,
+            (false, true, false) => self.octave_hops,
+            (false, true, true) => self.octave_up_hops,
+        };
+        if candidate.reads >= need {
+            let pitch = if self.source.bends { p } else { candidate.mean };
+            self.start(pitch, self.source.glide, emit);
+        } else {
+            self.candidate = Some(candidate);
+            self.trust(Some(up && !self.source.bends));
         }
     }
     /// Feeds one undelayed mono input sample. Events due at output time go to `emit`, in order.
     pub fn process(&mut self, mono: f32, mut emit: impl FnMut(NoteEvent)) {
         let d = self.detect[0].process(mono);
         let d = self.detect[1].process(d);
-        if !self.midi {
+        if !self.midi() {
             let a = d.abs();
             self.gate_env = if a > self.gate_env {
                 a
@@ -323,13 +702,14 @@ impl Tracker {
                 self.gate_env * self.gate_release
             };
             let level = gain_to_db(self.gate_env);
-            if level > self.gate_db {
+            let gate = self.source.gate_db;
+            if level > gate {
                 self.gate_hold = (self.rate * GATE_HOLD_MS * 0.001) as usize;
                 if !self.gate_open {
                     self.gate_open = true;
                     self.push(Kind::Onset);
                 }
-            } else if self.gate_open && level < self.gate_db - GATE_HYSTERESIS_DB {
+            } else if self.gate_open && level < gate - GATE_HYSTERESIS_DB {
                 if self.gate_hold == 0 {
                     self.gate_open = false;
                     self.push(Kind::Release);
@@ -409,8 +789,9 @@ pub trait Tracked {
     fn ahead(&mut self, _mono: f32) {}
     /// A note event due at the next `process` sample.
     fn event(&mut self, e: NoteEvent);
-    /// One sample of audio; `sounding` is the tracker's note state at this sample.
-    fn process(&mut self, x: [f32; 2], sounding: bool) -> [f32; 2];
+    /// One sample of audio and the tracker's note state at it. While the note is unsure
+    /// (see [`Fallback`]) the module should step back to something neutral.
+    fn process(&mut self, x: [f32; 2], note: NoteState) -> [f32; 2];
 }
 
 /// A tracker and the lookahead delay in front of one [`Tracked`] module: the standalone form.
@@ -446,6 +827,6 @@ impl Lookahead {
         self.delay[self.at] = x;
         self.at = (self.at + 1) % len;
         let y = self.delay[self.at];
-        module.process(y, self.tracker.sounding())
+        module.process(y, self.tracker.state())
     }
 }

plugins/common/dsp/tests/blocks.rs

@@ -1,7 +1,7 @@
 use common_dsp::meter::HarmonicMeter;
 use common_dsp::oversample::Oversampler;
 use common_dsp::svf::{Svf, SvfCoef};
-use common_dsp::tracker::{NoteEvent, Tracker, TrackerConfig};
+use common_dsp::tracker::{NoteEvent, PitchMode, PitchSource, Scale, Tracker, TrackerConfig};
 use common_dsp::{hz_to_midi, Saw};
 use std::f32::consts::TAU;
 
@@ -174,7 +174,7 @@ fn harmonic_meter_reads_saw_harmonics() {
 #[test]
 fn tracker_reports_notes_at_output_time() {
     let mut t = Tracker::new(RATE, TrackerConfig::BASS);
-    t.set(false, -42., false);
+    t.set(PitchSource::default());
     let l = t.latency();
     assert!(l < (0.08 * RATE) as usize, "{l}");
     let onset = 4800;
@@ -210,7 +210,11 @@ fn tracker_reports_notes_at_output_time() {
 #[test]
 fn tracker_delays_midi_by_the_latency() {
     let mut t = Tracker::new(RATE, TrackerConfig::BASS);
-    assert!(t.set(true, -42., true));
+    assert!(t.set(PitchSource {
+        mode: PitchMode::Midi,
+        glide: true,
+        ..PitchSource::default()
+    }));
     let l = t.latency();
     let mut events = vec![];
     for i in 0..l + 2000 {
@@ -248,3 +252,127 @@ fn tracker_delays_midi_by_the_latency() {
         ]
     );
 }
+
+#[test]
+fn stable_tracker_holds_its_notes_on_the_stem_corpus() {
+    let stable = PitchSource::default();
+    let bends = PitchSource {
+        bends: true,
+        ..stable
+    };
+    let (mut extra_stable, mut extra_bends) = (0., 0.);
+    for stem in common_dsp::stems::all(RATE) {
+        let s = common_dsp::stems::score(
+            RATE,
+            TrackerConfig::BASS,
+            stable,
+            &stem.samples,
+            &stem.truth,
+        );
+        let b =
+            common_dsp::stems::score(RATE, TrackerConfig::BASS, bends, &stem.samples, &stem.truth);
+        assert!(s.extra_starts <= 0.25, "{}: {s:?}", stem.name);
+        assert!(s.wrong <= 0.05, "{}: {s:?}", stem.name);
+        assert!(s.wrong <= b.wrong + 0.005, "{}: {s:?} vs {b:?}", stem.name);
+        extra_stable += s.extra_starts;
+        extra_bends += b.extra_starts;
+    }
+    // Follow bends keeps the fast 0.1 behaviour, which flickers on formant basses.
+    assert!(
+        extra_bends > 10. * extra_stable.max(1.),
+        "{extra_stable} vs {extra_bends}"
+    );
+}
+
+#[test]
+fn tracker_turns_inactive_when_reads_stop_agreeing() {
+    let mut t = Tracker::new(RATE, TrackerConfig::BASS);
+    t.set(PitchSource::default());
+    let mut saw = Saw::new(RATE, 55.);
+    let mut seed = 1u32;
+    let mut active = vec![];
+    for i in 0..(RATE * 1.5) as usize {
+        seed ^= seed << 13;
+        seed ^= seed >> 17;
+        seed ^= seed << 5;
+        let noise = seed as f32 / u32::MAX as f32 - 0.5;
+        let x = if i < 24000 { 0.5 * saw.sample() } else { noise };
+        t.process(x, |_| {});
+        active.push(t.active());
+    }
+    let l = t.latency();
+    assert!(active[l + 12000..l + 23000].iter().all(|a| *a));
+    // Unreadable sound is no evidence against the note, so trust fades slowly: growls read
+    // only now and then. Within half a second of noise, tracked processing stops acting.
+    assert!(active[l + 48000..].iter().all(|a| !*a));
+}
+
+#[test]
+fn note_mode_plays_the_set_note_on_each_onset() {
+    let mut t = Tracker::new(RATE, TrackerConfig::BASS);
+    t.set(PitchSource {
+        mode: PitchMode::Note,
+        note: 29,
+        ..PitchSource::default()
+    });
+    let mut saw = Saw::new(RATE, 220.);
+    let mut events = vec![];
+    for i in 0..48000 {
+        let x = if (4800..20000).contains(&i) || i >= 30000 {
+            0.5 * saw.sample()
+        } else {
+            0.
+        };
+        t.process(x, |e| events.push(e));
+        if i == 15000 {
+            assert!(t.active());
+        }
+    }
+    let starts: Vec<_> = events
+        .iter()
+        .filter_map(|e| match e {
+            NoteEvent::Start { pitch, .. } => Some(*pitch),
+            _ => None,
+        })
+        .collect();
+    assert_eq!(starts, vec![29., 29.]);
+    assert!(!events.iter().any(|e| matches!(e, NoteEvent::Move { .. })));
+}
+
+#[test]
+fn key_lock_snaps_reads_to_the_scale() {
+    // F minor: F G Ab Bb C Db Eb. F#1 (30) leans to G1 when read sharp.
+    assert_eq!(Scale::Minor.snap(29, 30.4), 31.);
+    assert_eq!(Scale::Minor.snap(29, 29.6), 29.);
+    assert_eq!(Scale::Major.snap(0, 61.), 60.);
+    assert_eq!(Scale::Root.snap(29, 40.6), 41.);
+    assert_eq!(Scale::Root.snap(29, 35.4), 41.);
+    assert_eq!(Scale::Free.snap(29, 30.37), 30.37);
+}
+
+#[test]
+fn key_lock_keeps_a_drifting_wobble_on_its_root() {
+    let stem = common_dsp::stems::all(RATE)
+        .into_iter()
+        .find(|s| s.name == "wobble")
+        .unwrap();
+    let free = PitchSource::default();
+    let root = PitchSource {
+        note: 31,
+        scale: Scale::Root,
+        ..free
+    };
+    let f = common_dsp::stems::score(RATE, TrackerConfig::BASS, free, &stem.samples, &stem.truth);
+    let r = common_dsp::stems::score(RATE, TrackerConfig::BASS, root, &stem.samples, &stem.truth);
+    assert!(r.unsure + r.wrong < f.unsure + f.wrong, "{f:?} vs {r:?}");
+    assert!(r.wrong <= 0.02, "{r:?}");
+}
+
+#[test]
+fn note_names_parse_back() {
+    for n in 0..=127u8 {
+        assert_eq!(common_dsp::parse_note(&common_dsp::note_name(n)), Some(n));
+    }
+    assert_eq!(common_dsp::parse_note(" f1 "), Some(29));
+    assert_eq!(common_dsp::parse_note("H2"), None);
+}

plugins/common/params/Cargo.toml

@@ -0,0 +1,9 @@
+[package]
+name = "common-params"
+version = "0.1.0"
+edition = "2021"
+license = "ISC"
+
+[dependencies]
+nih_plug = { git = "https://github.com/robbert-vdh/nih-plug.git", rev = "de421011f41a6d10fc8c7a6084e4f4dee0143683", default-features = false }
+common-dsp = { path = "../dsp" }

plugins/common/params/src/lib.rs

@@ -0,0 +1,121 @@
+//! Host parameters shared by every tracked plugin: Note mode's note, the key lock and
+//! Follow bends. Plugins nest [`PitchParams`] in their own parameter struct.
+use common_dsp::tracker::{Pitch, Scale, NOTE_MAX, NOTE_MIN};
+use common_dsp::note_name;
+use nih_plug::prelude::*;
+use std::sync::Arc;
+
+#[derive(Enum, Debug, PartialEq, Eq, Clone, Copy)]
+pub enum ScaleParam {
+    #[id = "free"]
+    #[name = "Off"]
+    Free,
+    #[id = "minor"]
+    Minor,
+    #[id = "major"]
+    Major,
+    #[id = "root"]
+    #[name = "Root only"]
+    Root,
+}
+impl From<ScaleParam> for Scale {
+    fn from(s: ScaleParam) -> Self {
+        match s {
+            ScaleParam::Free => Scale::Free,
+            ScaleParam::Minor => Scale::Minor,
+            ScaleParam::Major => Scale::Major,
+            ScaleParam::Root => Scale::Root,
+        }
+    }
+}
+impl From<Scale> for ScaleParam {
+    fn from(s: Scale) -> Self {
+        match s {
+            Scale::Free => ScaleParam::Free,
+            Scale::Minor => ScaleParam::Minor,
+            Scale::Major => ScaleParam::Major,
+            Scale::Root => ScaleParam::Root,
+        }
+    }
+}
+
+#[derive(Params)]
+pub struct PitchParams {
+    /// The note played in Note mode; its pitch class is the key root.
+    #[id = "note"]
+    pub note: IntParam,
+    #[id = "scale"]
+    pub scale: EnumParam<ScaleParam>,
+    #[id = "bends"]
+    pub bends: BoolParam,
+}
+impl Default for PitchParams {
+    fn default() -> Self {
+        let d = Pitch::default();
+        Self {
+            note: IntParam::new(
+                "Note",
+                d.note as i32,
+                IntRange::Linear {
+                    min: NOTE_MIN as i32,
+                    max: NOTE_MAX as i32,
+                },
+            )
+            .with_value_to_string(Arc::new(|v| note_name(v.clamp(0, 127) as u8)))
+            .with_string_to_value(Arc::new(|s| parse_note(s).map(i32::from))),
+            scale: EnumParam::new("Key lock", ScaleParam::Free),
+            bends: BoolParam::new("Follow bends", d.bends),
+        }
+    }
+}
+impl PitchParams {
+    pub fn pitch(&self) -> Pitch {
+        Pitch {
+            note: (self.note.value().clamp(NOTE_MIN as i32, NOTE_MAX as i32)) as u8,
+            scale: self.scale.value().into(),
+            bends: self.bends.value(),
+        }
+    }
+    /// Pushes editor changes to the host, one gesture per change.
+    pub fn apply(&self, setter: &ParamSetter, old: &Pitch, new: &Pitch) {
+        if old.note != new.note {
+            setter.begin_set_parameter(&self.note);
+            setter.set_parameter(&self.note, new.note as i32);
+            setter.end_set_parameter(&self.note);
+        }
+        if old.scale != new.scale {
+            setter.begin_set_parameter(&self.scale);
+            setter.set_parameter(&self.scale, new.scale.into());
+            setter.end_set_parameter(&self.scale);
+        }
+        if old.bends != new.bends {
+            setter.begin_set_parameter(&self.bends);
+            setter.set_parameter(&self.bends, new.bends);
+            setter.end_set_parameter(&self.bends);
+        }
+    }
+}
+
+/// Reads a note name such as "F1" within the Note range.
+pub fn parse_note(text: &str) -> Option<u8> {
+    common_dsp::parse_note(text).filter(|n| (NOTE_MIN..=NOTE_MAX).contains(n))
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    #[test]
+    fn note_names_round_trip() {
+        for n in NOTE_MIN..=NOTE_MAX {
+            assert_eq!(parse_note(&note_name(n)), Some(n));
+        }
+        assert_eq!(parse_note("f1"), Some(29));
+        assert_eq!(parse_note("H2"), None);
+    }
+    #[test]
+    fn scale_maps_both_ways() {
+        for s in [Scale::Free, Scale::Minor, Scale::Major, Scale::Root] {
+            assert_eq!(Scale::from(ScaleParam::from(s)), s);
+        }
+    }
+}

plugins/common/ui/Cargo.toml

@@ -6,3 +6,4 @@ license.workspace = true
 
 [dependencies]
 egui = "0.31.1"
+common-dsp = { path = "../dsp" }

plugins/common/ui/src/lib.rs

@@ -1,4 +1,6 @@
 //! Shared hardware look for every plugin editor: palette, fonts, knobs, panels.
+use common_dsp::note_name;
+use common_dsp::tracker::{Pitch, PitchMode, Scale, NOTE_MAX, NOTE_MIN};
 use egui::{self, Color32, FontId, Pos2, Rect, RichText, Sense, Stroke, Vec2};
 
 // Dark anodized hardware: graphite surfaces, one signal colour, steel data traces.
@@ -359,3 +361,168 @@ pub fn meter(ui: &mut egui::Ui, label: &str, db: f32, color: Color32, width: f32
         );
     });
 }
+
+const PITCH_CLASSES: [&str; 12] = [
+    "C", "C#", "D", "D#", "E", "F", "F#", "G", "G#", "A", "A#", "B",
+];
+fn scale_name(scale: Scale) -> &'static str {
+    match scale {
+        Scale::Free => "off",
+        Scale::Minor => "minor",
+        Scale::Major => "major",
+        Scale::Root => "root only",
+    }
+}
+/// Short status of the pitch source for readout lines: "detecting pitch in F minor".
+pub fn pitch_status(mode: PitchMode, pitch: &Pitch) -> String {
+    match (mode, pitch.scale) {
+        (PitchMode::Audio, Scale::Free) => "detecting pitch".into(),
+        (PitchMode::Audio, s) => format!(
+            "detecting pitch, key {} {}",
+            PITCH_CLASSES[pitch.note as usize % 12],
+            scale_name(s)
+        ),
+        (PitchMode::Midi, _) => "following MIDI".into(),
+        (PitchMode::Note, _) => format!("fixed on {}", note_name(pitch.note)),
+    }
+}
+/// Pitch source switch for a header's right-to-left row: AUDIO, MIDI and NOTE, then a button
+/// that opens Note mode's note, or the key lock and Follow bends for detection.
+pub fn pitch_from(ui: &mut egui::Ui, mode: &mut PitchMode, pitch: &mut Pitch) {
+    let id = ui.make_persistent_id("pitch-detail");
+    let detail = match *mode {
+        PitchMode::Note => Some(note_name(pitch.note)),
+        PitchMode::Audio => Some(match pitch.scale {
+            Scale::Free if pitch.bends => "BENDS".into(),
+            Scale::Free => "KEY OFF".into(),
+            s => format!(
+                "{} {}",
+                PITCH_CLASSES[pitch.note as usize % 12],
+                match s {
+                    Scale::Minor => "MIN",
+                    Scale::Major => "MAJ",
+                    _ => "ROOT",
+                }
+            ),
+        }),
+        PitchMode::Midi => None,
+    };
+    if let Some(detail) = detail {
+        let help = if *mode == PitchMode::Note {
+            "The note this plugin follows. Nothing is detected: set the drop's root."
+        } else {
+            "Key lock and Follow bends for detection."
+        };
+        let r = ui
+            .button(RichText::new(detail).size(13.).color(ACCENT))
+            .on_hover_text(help);
+        if r.clicked() {
+            ui.memory_mut(|m| m.toggle_popup(id));
+        }
+        let note_mode = *mode == PitchMode::Note;
+        egui::popup_below_widget(
+            ui,
+            id,
+            &r,
+            egui::PopupCloseBehavior::CloseOnClickOutside,
+            |ui| {
+                ui.set_min_width(220.);
+                if note_mode {
+                    pitch_note(ui, pitch, true);
+                } else {
+                    caption(ui, "KEY LOCK");
+                    ui.horizontal(|ui| {
+                        for s in [Scale::Free, Scale::Minor, Scale::Major, Scale::Root] {
+                            let help = match s {
+                                Scale::Free => "Any pitch, also between notes.",
+                                Scale::Minor => "Only notes of the natural minor scale.",
+                                Scale::Major => "Only notes of the major scale.",
+                                Scale::Root => "Only the root: detection picks the octave.",
+                            };
+                            let label = RichText::new(scale_name(s).to_uppercase()).size(12.);
+                            if ui
+                                .selectable_label(pitch.scale == s, label)
+                                .on_hover_text(help)
+                                .clicked()
+                            {
+                                pitch.scale = s;
+                            }
+                        }
+                    });
+                    if pitch.scale != Scale::Free {
+                        ui.add_space(4.);
+                        caption(ui, "ROOT");
+                        pitch_note(ui, pitch, false);
+                    }
+                    ui.add_space(6.);
+                    ui.checkbox(&mut pitch.bends, "Follow bends").on_hover_text(
+                        "Retune on every bend and switch notes within 10 ms. Fast, but it \
+                         flickers on growls. Off holds each note until a new one is clear.",
+                    );
+                }
+            },
+        );
+    }
+    for (m, label, help) in [
+        (
+            PitchMode::Note,
+            "NOTE",
+            "You set the note; the audio only starts and stops it. Nothing is detected.",
+        ),
+        (
+            PitchMode::Midi,
+            "MIDI",
+            "Notes from MIDI input. In FL, set the channel's MIDI output port and this \
+             effect's input port to the same number.",
+        ),
+        (
+            PitchMode::Audio,
+            "AUDIO",
+            "Detect the pitch from the audio. When detection is unsure, tracked processing \
+             steps back instead of guessing.",
+        ),
+    ] {
+        let r = ui
+            .selectable_label(*mode == m, RichText::new(label).size(13.))
+            .on_hover_text(help);
+        if r.clicked() {
+            *mode = m;
+        }
+    }
+    caption(ui, "PITCH FROM");
+}
+/// Twelve pitch-class buttons, and octave steps when `octave` is set.
+fn pitch_note(ui: &mut egui::Ui, pitch: &mut Pitch, octave: bool) {
+    let class = pitch.note % 12;
+    let base = pitch.note - class;
+    for row in [0..6, 6..12] {
+        ui.horizontal(|ui| {
+            for c in row {
+                let r = ui.add_sized(
+                    [30., 22.],
+                    egui::SelectableLabel::new(class == c as u8, PITCH_CLASSES[c]),
+                );
+                if r.clicked() {
+                    pitch.note = (base + c as u8).clamp(NOTE_MIN, NOTE_MAX);
+                }
+            }
+        });
+    }
+    if octave {
+        ui.horizontal(|ui| {
+            caption(ui, "OCTAVE");
+            if ui.button("−").clicked() && pitch.note >= NOTE_MIN + 12 {
+                pitch.note -= 12;
+            }
+            ui.label(
+                RichText::new(format!("{}", pitch.note as i32 / 12 - 1))
+                    .monospace()
+                    .color(TEXT),
+            );
+            if ui.button("+").clicked() && pitch.note + 12 <= NOTE_MAX {
+                pitch.note += 12;
+            }
+            ui.label(RichText::new(note_name(pitch.note)).color(ACCENT));
+        });
+    }
+}

plugins/crucible/plugin/Cargo.lock

@@ -309,11 +309,15 @@ dependencies = [
 [[package]]
 name = "common-dsp"
 version = "0.1.0"
+dependencies = [
+ "serde",
+]
 
 [[package]]
 name = "common-ui"
 version = "0.1.0"
 dependencies = [
+ "common-dsp",
  "egui",
 ]
 

plugins/forge/core/src/lib.rs

@@ -7,7 +7,7 @@
 //! its audio by its own latency, so the strip's latency never changes. Allocation-free after
 //! `new`.
 mod settings;
-use common_dsp::tracker::{NoteEvent, Tracked, Tracker, TrackerConfig};
+use common_dsp::tracker::{NoteEvent, NoteState, Tracked, Tracker, TrackerConfig};
 use common_dsp::{coefficient, hz_to_midi};
 pub use settings::{Settings, Source, Stage, ORDERS, STAGES};
 
@@ -44,7 +44,7 @@ impl Default for AnalyzerFrame {
 struct Slot {
     events: [NoteEvent; EVENTS],
     len: usize,
-    sounding: bool,
+    note: NoteState,
     /// The undelayed input, one lookahead ahead of the audio this slot belongs to.
     ahead: f32,
 }
@@ -53,7 +53,7 @@ impl Default for Slot {
         Self {
             events: [NoteEvent::Stop; EVENTS],
             len: 0,
-            sounding: false,
+            note: NoteState::default(),
             ahead: 0.,
         }
     }
@@ -155,7 +155,8 @@ impl Engine {
     /// Tracker settings and how far back each position reads the note events.
     fn route(&mut self, s: &Settings) {
         // Each module decides itself whether a legato note slides.
-        self.tracker.set(s.source == Source::Midi, s.gate, true);
+        self.tracker
+            .set(s.pitch.source(s.source.mode(), s.gate, true));
         let mut at = 0;
         for (i, stage) in s.order.into_iter().enumerate() {
             self.offsets[i] = at;
@@ -198,7 +199,7 @@ impl Engine {
             ..Slot::default()
         };
         self.tracker.process(mono, |e| slot.push(e));
-        slot.sounding = self.tracker.sounding();
+        slot.note = self.tracker.state();
         let len = self.line.len();
         self.line_at = (self.line_at + 1) % len;
         self.line[self.line_at] = slot;
@@ -221,7 +222,7 @@ impl Engine {
             for &e in &slot.events[..slot.len] {
                 m.event(e);
             }
-            v = m.process(v, slot.sounding);
+            v = m.process(v, slot.note);
         }
 
         // The pitch at the output: the oldest slot is the last module's input time minus its
@@ -231,7 +232,7 @@ impl Engine {
             self.pitch.event(false, e);
         }
         self.pitch.step(1.);
-        self.sounding = last.sounding;
+        self.sounding = last.note.sure;
 
         let len = self.dry.len();
         self.dry_at = (self.dry_at + 1) % len;

plugins/forge/core/src/settings.rs

@@ -1,4 +1,5 @@
 //! Host-independent controls of the strip and its modules.
+use common_dsp::tracker::{Pitch, PitchMode};
 use serde::{Deserialize, Serialize};
 
 #[derive(Debug, Clone, Copy, Serialize, Deserialize, PartialEq, Eq, Default)]
@@ -8,6 +9,24 @@ pub enum Source {
     Audio,
     /// Notes come from MIDI note input.
     Midi,
+    /// Note starts are detected, the pitch is the set note: nothing is guessed.
+    Note,
+}
+impl Source {
+    pub fn mode(self) -> PitchMode {
+        match self {
+            Source::Audio => PitchMode::Audio,
+            Source::Midi => PitchMode::Midi,
+            Source::Note => PitchMode::Note,
+        }
+    }
+    pub fn from_mode(mode: PitchMode) -> Self {
+        match mode {
+            PitchMode::Audio => Source::Audio,
+            PitchMode::Midi => Source::Midi,
+            PitchMode::Note => Source::Note,
+        }
+    }
 }
 
 /// One module of the strip.
@@ -45,6 +64,9 @@ pub const ORDERS: [[Stage; STAGES]; 6] = [
 pub struct Settings {
     /// Pitch source of the one tracker every module follows.
     pub source: Source,
+    /// Note mode's note, the key lock and Follow bends.
+    #[serde(default)]
+    pub pitch: Pitch,
     /// Detection threshold in dBFS for note starts (Audio source).
     pub gate: f32,
     /// Modules in processing order.
@@ -60,6 +82,7 @@ impl Default for Settings {
     fn default() -> Self {
         Self {
             source: Source::Audio,
+            pitch: Pitch::default(),
             gate: lathe_core::Settings::default().gate,
             order: ORDERS[0],
             lathe: lathe_core::Settings::default(),
@@ -71,6 +94,7 @@ impl Default for Settings {
 }
 impl Settings {
     pub fn validate(&self) -> Result<(), &'static str> {
+        self.pitch.validate()?;
         let ok = (-60.0..=-20.).contains(&self.gate) && ORDERS.contains(&self.order);
         if !ok {
             return Err("invalid settings");
@@ -94,26 +118,17 @@ impl Settings {
             Stage::Knurl => self.knurl.bypass = !on,
         }
     }
-    /// Copies the strip's pitch source and gate into every module.
+    /// Copies the strip's pitch source, pitch details and gate into every module.
     pub fn share(&mut self) {
-        let midi = self.source == Source::Midi;
+        let mode = self.source.mode();
         self.lathe.gate = self.gate;
         self.temper.gate = self.gate;
         self.knurl.gate = self.gate;
-        self.lathe.source = if midi {
-            lathe_core::Source::Midi
-        } else {
-            lathe_core::Source::Audio
-        };
-        self.temper.source = if midi {
-            temper_core::Source::Midi
-        } else {
-            temper_core::Source::Audio
-        };
-        self.knurl.source = if midi {
-            knurl_core::Source::Midi
-        } else {
-            knurl_core::Source::Audio
-        };
+        self.lathe.pitch = self.pitch;
+        self.temper.pitch = self.pitch;
+        self.knurl.pitch = self.pitch;
+        self.lathe.source = lathe_core::Source::from_mode(mode);
+        self.temper.source = temper_core::Source::from_mode(mode);
+        self.knurl.source = knurl_core::Source::from_mode(mode);
     }
 }

plugins/forge/plugin/Cargo.lock

@@ -309,11 +309,23 @@ dependencies = [
 [[package]]
 name = "common-dsp"
 version = "0.1.0"
+dependencies = [
+ "serde",
+]
+
+[[package]]
+name = "common-params"
+version = "0.1.0"
+dependencies = [
+ "common-dsp",
+ "nih_plug",
+]
 
 [[package]]
 name = "common-ui"
 version = "0.1.0"
 dependencies = [
+ "common-dsp",
  "egui",
 ]
 
@@ -646,6 +658,7 @@ name = "forge"
 version = "0.1.0"
 dependencies = [
  "clap-sys",
+ "common-params",
  "crossbeam-queue",
  "forge-core",
  "forge-ui",

plugins/forge/plugin/Cargo.toml

@@ -13,6 +13,7 @@ crate-type = ["cdylib", "rlib"]
 nih_plug = { git = "https://github.com/robbert-vdh/nih-plug.git", rev = "de421011f41a6d10fc8c7a6084e4f4dee0143683", default-features = false }
 nih_plug_egui = { git = "https://github.com/robbert-vdh/nih-plug.git", rev = "de421011f41a6d10fc8c7a6084e4f4dee0143683" }
 forge-core = { path = "../core" }
+common-params = { path = "../../common/params" }
 lathe-core = { path = "../../lathe/core" }
 temper-core = { path = "../../temper/core" }
 knurl-core = { path = "../../knurl/core" }

plugins/forge/plugin/src/params.rs

@@ -1,3 +1,4 @@
+use common_params::PitchParams;
 use forge_core::{Settings, Source, ORDERS};
 use knurl_core::{Seed, GRIT_OFF, STEPS, STEP_MIN};
 use lathe_core::HARMONICS;
@@ -13,6 +14,26 @@ pub enum SourceParam {
     #[id = "midi"]
     #[name = "MIDI"]
     Midi,
+    #[id = "note"]
+    Note,
+}
+impl From<SourceParam> for Source {
+    fn from(s: SourceParam) -> Self {
+        match s {
+            SourceParam::Audio => Source::Audio,
+            SourceParam::Midi => Source::Midi,
+            SourceParam::Note => Source::Note,
+        }
+    }
+}
+impl From<Source> for SourceParam {
+    fn from(s: Source) -> Self {
+        match s {
+            Source::Audio => SourceParam::Audio,
+            Source::Midi => SourceParam::Midi,
+            Source::Note => SourceParam::Note,
+        }
+    }
 }
 /// The six orders of `ORDERS`, in the same order.
 #[derive(Enum, Debug, PartialEq, Eq, Clone, Copy)]
@@ -281,6 +302,8 @@ pub struct ForgeParams {
     pub editor: Arc<EguiState>,
     #[id = "source"]
     pub source: EnumParam<SourceParam>,
+    #[nested(group = "Pitch")]
+    pub pitch: PitchParams,
     #[id = "gate"]
     pub gate: FloatParam,
     #[id = "order"]
@@ -300,6 +323,7 @@ impl Default for ForgeParams {
         Self {
             editor: EguiState::from_size(forge_ui::WIDTH, forge_ui::HEIGHT),
             source: EnumParam::new("Pitch source", SourceParam::Audio),
+            pitch: PitchParams::default(),
             gate: linear("Gate", d.gate, -60., -20., " dB"),
             order: EnumParam::new("Order", OrderParam::LatheTemperKnurl),
             bypass: BoolParam::new("Bypass", false).make_bypass(),
@@ -401,10 +425,8 @@ impl ForgeParams {
             .unwrap_or(0);
         let curve = self.temper.curve.value();
         let mut s = Settings {
-            source: match self.source.value() {
-                SourceParam::Audio => Source::Audio,
-                SourceParam::Midi => Source::Midi,
-            },
+            source: self.source.value().into(),
+            pitch: self.pitch.pitch(),
             gate: self.gate.value(),
             order: ORDERS[order],
             lathe: lathe_core::Settings {
@@ -576,11 +598,13 @@ impl ForgeParams {
             old.knurl.steps as i32,
             new.knurl.steps as i32,
         );
-        let source = |s: Source| match s {
-            Source::Audio => SourceParam::Audio,
-            Source::Midi => SourceParam::Midi,
-        };
-        switch(setter, &self.source, source(old.source), source(new.source));
+        switch(
+            setter,
+            &self.source,
+            SourceParam::from(old.source),
+            SourceParam::from(new.source),
+        );
+        self.pitch.apply(setter, &old.pitch, &new.pitch);
         let order =
             |s: &Settings| ORDER_PARAMS[ORDERS.iter().position(|o| *o == s.order).unwrap_or(0)];
         switch(setter, &self.order, order(old), order(new));

plugins/forge/ui/src/lib.rs

@@ -129,13 +129,9 @@ pub fn show(ui: &mut egui::Ui, settings: &mut Settings, state: &mut State) {
             settings.bypass = !settings.bypass;
         }
         ui.separator();
-        for (source, label) in [(Source::Midi, "MIDI"), (Source::Audio, "AUDIO")] {
-            let r = ui.selectable_label(settings.source == source, RichText::new(label).size(13.));
-            if r.clicked() {
-                settings.source = source;
-            }
-        }
-        caption(ui, "PITCH FROM");
+        let mut mode = settings.source.mode();
+        pitch_from(ui, &mut mode, &mut settings.pitch);
+        settings.source = Source::from_mode(mode);
     });
     ui.add_space(6.);
     panel(ui, |ui| {

plugins/knurl/core/src/lib.rs

@@ -8,7 +8,7 @@
 //! after `new`; mono-safe (both channels get the same treatment).
 mod settings;
 use common_dsp::svf::{Svf, SvfCoef};
-use common_dsp::tracker::{Lookahead, NoteEvent, PitchFollower, Tracked, TrackerConfig};
+use common_dsp::tracker::{Lookahead, NoteEvent, NoteState, PitchFollower, Tracked, TrackerConfig};
 use common_dsp::{coefficient, db_to_gain, hz_to_midi};
 pub use settings::{Seed, Settings, Source, GRIT_OFF, PATTERNS, STEPS, STEP_MIN};
 
@@ -402,8 +402,10 @@ impl Tracked for Module {
         };
         self.pitch.event(self.settings.snap, e);
     }
-    fn process(&mut self, x: [f32; 2], sounding: bool) -> [f32; 2] {
-        self.run(x, sounding)
+    fn process(&mut self, x: [f32; 2], note: NoteState) -> [f32; 2] {
+        // The texture needs a trusted cycle clock: it fades out while tracking is unsure, as
+        // it does between notes.
+        self.run(x, note.sure)
     }
 }
 
@@ -444,7 +446,7 @@ impl Engine {
     fn set_tracker(&mut self, s: &Settings) {
         self.lookahead
             .tracker
-            .set(s.source == Source::Midi, s.gate, false);
+            .set(s.pitch.source(s.source.mode(), s.gate, false));
     }
     pub fn reset(&mut self) {
         self.lookahead.reset();

plugins/knurl/core/src/settings.rs

@@ -1,4 +1,5 @@
 //! Host-independent controls. Gains in dB; amounts relative to one cycle in percent.
+use common_dsp::tracker::{Pitch, PitchMode};
 use serde::{Deserialize, Serialize};
 
 /// Pattern steps: one per cycle, repeating.
@@ -14,6 +15,24 @@ pub enum Source {
     Audio,
     /// Notes come from MIDI note input.
     Midi,
+    /// Note starts are detected, the pitch is the set note: nothing is guessed.
+    Note,
+}
+impl Source {
+    pub fn mode(self) -> PitchMode {
+        match self {
+            Source::Audio => PitchMode::Audio,
+            Source::Midi => PitchMode::Midi,
+            Source::Note => PitchMode::Note,
+        }
+    }
+    pub fn from_mode(mode: PitchMode) -> Self {
+        match mode {
+            PitchMode::Audio => Source::Audio,
+            PitchMode::Midi => Source::Midi,
+            PitchMode::Note => Source::Note,
+        }
+    }
 }
 
 #[derive(Debug, Clone, Copy, Serialize, Deserialize, PartialEq, Eq, Default)]
@@ -29,6 +48,9 @@ pub enum Seed {
 #[serde(deny_unknown_fields)]
 pub struct Settings {
     pub source: Source,
+    /// Note mode's note, the key lock and Follow bends.
+    #[serde(default)]
+    pub pitch: Pitch,
     /// Gain per pattern step, 0 down to `STEP_MIN`.
     pub pattern: [f32; STEPS],
     /// Steps that get a grit burst.
@@ -104,6 +126,7 @@ impl Default for Settings {
     fn default() -> Self {
         let mut s = Self {
             source: Source::Audio,
+            pitch: Pitch::default(),
             pattern: [0.; STEPS],
             grit_steps: [true; STEPS],
             steps: 1,
@@ -127,6 +150,7 @@ impl Default for Settings {
 }
 impl Settings {
     pub fn validate(&self) -> Result<(), &'static str> {
+        self.pitch.validate()?;
         let finite = [
             self.edge,
             self.level_jitter,

plugins/knurl/plugin/Cargo.lock

@@ -309,11 +309,23 @@ dependencies = [
 [[package]]
 name = "common-dsp"
 version = "0.1.0"
+dependencies = [
+ "serde",
+]
+
+[[package]]
+name = "common-params"
+version = "0.1.0"
+dependencies = [
+ "common-dsp",
+ "nih_plug",
+]
 
 [[package]]
 name = "common-ui"
 version = "0.1.0"
 dependencies = [
+ "common-dsp",
  "egui",
 ]
 
@@ -864,6 +876,7 @@ name = "knurl"
 version = "0.2.0"
 dependencies = [
  "clap-sys",
+ "common-params",
  "crossbeam-queue",
  "knurl-core",
  "knurl-ui",

plugins/knurl/plugin/Cargo.toml

@@ -13,6 +13,7 @@ crate-type = ["cdylib", "rlib"]
 nih_plug = { git = "https://github.com/robbert-vdh/nih-plug.git", rev = "de421011f41a6d10fc8c7a6084e4f4dee0143683", default-features = false }
 nih_plug_egui = { git = "https://github.com/robbert-vdh/nih-plug.git", rev = "de421011f41a6d10fc8c7a6084e4f4dee0143683" }
 knurl-core = { path = "../core" }
+common-params = { path = "../../common/params" }
 knurl-ui = { path = "../ui" }
 crossbeam-queue = "0.3"
 serde = { version = "1", features = ["derive"] }

plugins/knurl/plugin/src/params.rs

@@ -1,3 +1,4 @@
+use common_params::PitchParams;
 use knurl_core::{Seed, Settings, Source, GRIT_OFF, STEPS, STEP_MIN};
 use nih_plug::prelude::*;
 use nih_plug_egui::EguiState;
@@ -10,6 +11,26 @@ pub enum SourceParam {
     #[id = "midi"]
     #[name = "MIDI"]
     Midi,
+    #[id = "note"]
+    Note,
+}
+impl From<SourceParam> for Source {
+    fn from(s: SourceParam) -> Self {
+        match s {
+            SourceParam::Audio => Source::Audio,
+            SourceParam::Midi => Source::Midi,
+            SourceParam::Note => Source::Note,
+        }
+    }
+}
+impl From<Source> for SourceParam {
+    fn from(s: Source) -> Self {
+        match s {
+            Source::Audio => SourceParam::Audio,
+            Source::Midi => SourceParam::Midi,
+            Source::Note => SourceParam::Note,
+        }
+    }
 }
 #[derive(Enum, Debug, PartialEq, Eq, Clone, Copy)]
 pub enum SeedParam {
@@ -50,6 +71,8 @@ pub struct KnurlParams {
     pub pattern: RwLock<Pattern>,
     #[id = "source"]
     pub source: EnumParam<SourceParam>,
+    #[nested(group = "Pitch")]
+    pub pitch: PitchParams,
     #[id = "seed"]
     pub seed: EnumParam<SeedParam>,
     #[id = "steps"]
@@ -86,6 +109,7 @@ impl Default for KnurlParams {
             editor: EguiState::from_size(knurl_ui::WIDTH, knurl_ui::HEIGHT),
             pattern: RwLock::new(Pattern::default()),
             source: EnumParam::new("Pitch source", SourceParam::Audio),
+            pitch: PitchParams::default(),
             seed: EnumParam::new("Random", SeedParam::Same),
             steps: IntParam::new(
                 "Steps",
@@ -131,10 +155,8 @@ impl KnurlParams {
     pub fn settings(&self, last: &Pattern) -> Settings {
         let pattern = self.pattern.try_read().map(|p| *p).unwrap_or(*last);
         Settings {
-            source: match self.source.value() {
-                SourceParam::Audio => Source::Audio,
-                SourceParam::Midi => Source::Midi,
-            },
+            source: self.source.value().into(),
+            pitch: self.pitch.pitch(),
             pattern: pattern.gains.map(|g| {
                 if g.is_finite() {
                     g.clamp(STEP_MIN, 0.)
@@ -238,12 +260,9 @@ impl KnurlParams {
             switch(setter, &self.bypass, new.bypass);
         }
         if new.source != old.source {
-            let v = match new.source {
-                Source::Audio => SourceParam::Audio,
-                Source::Midi => SourceParam::Midi,
-            };
-            switch(setter, &self.source, v);
+            switch(setter, &self.source, new.source.into());
         }
+        self.pitch.apply(setter, &old.pitch, &new.pitch);
         if new.seed != old.seed {
             let v = match new.seed {
                 Seed::Same => SeedParam::Same,

plugins/knurl/ui/src/lib.rs

@@ -78,13 +78,9 @@ pub fn show(ui: &mut egui::Ui, settings: &mut Settings, state: &mut State) {
             settings.bypass = !settings.bypass;
         }
         ui.separator();
-        for (source, label) in [(Source::Midi, "MIDI"), (Source::Audio, "AUDIO")] {
-            let r = ui.selectable_label(settings.source == source, RichText::new(label).size(13.));
-            if r.clicked() {
-                settings.source = source;
-            }
-        }
-        caption(ui, "PITCH FROM");
+        let mut mode = settings.source.mode();
+        pitch_from(ui, &mut mode, &mut settings.pitch);
+        settings.source = Source::from_mode(mode);
     });
     body(ui, settings, state);
     ui.separator();

plugins/lathe/core/src/lib.rs

@@ -6,7 +6,9 @@
 mod settings;
 use common_dsp::meter::HarmonicMeter;
 use common_dsp::svf::{Svf, SvfCoef};
-use common_dsp::tracker::{Lookahead, NoteEvent, PitchFollower, Tracked, TrackerConfig};
+use common_dsp::tracker::{
+    Fallback, Lookahead, NoteEvent, NoteState, PitchFollower, Tracked, TrackerConfig,
+};
 use common_dsp::{coefficient, db_to_gain, hz_to_midi};
 pub use settings::{Settings, Source, GAIN_MAX, GAIN_MIN, HARMONICS};
 
@@ -22,8 +24,10 @@ const GAIN_MS: f32 = 20.;
 pub struct AnalyzerFrame {
     /// Fundamental the filters are tuned to, 0 before the first note.
     pub hz: f32,
-    /// Sounding note, rounded; None between notes.
+    /// Sounding note, rounded; None between notes and while tracking is unsure.
     pub note: Option<u8>,
+    /// Tracking is unsure, so the audio passes unchanged.
+    pub neutral: bool,
     /// Harmonic levels in dBFS of the delayed input and of the output (index 0 = fundamental).
     pub input: [f32; HARMONICS],
     pub output: [f32; HARMONICS],
@@ -35,6 +39,7 @@ impl Default for AnalyzerFrame {
         Self {
             hz: 0.,
             note: None,
+            neutral: false,
             input: [-120.; HARMONICS],
             output: [-120.; HARMONICS],
             latency: 0,
@@ -64,7 +69,11 @@ pub struct Module {
     bypass: f32,
     meter_in: HarmonicMeter,
     meter_out: HarmonicMeter,
+    /// A sure note sounds: the readout shows it.
     sounding: bool,
+    fallback: Fallback,
+    /// Unsure tracking: every band fades to 0 dB and the audio passes unchanged.
+    neutral: bool,
     /// Smoothed controls start at the next settings instead of gliding from defaults.
     fresh: bool,
 }
@@ -103,6 +112,8 @@ impl Module {
             meter_in: HarmonicMeter::new(rate, 85.),
             meter_out: HarmonicMeter::new(rate, 85.),
             sounding: false,
+            fallback: Fallback::default(),
+            neutral: false,
             fresh: true,
         };
         m.set_settings(settings)?;
@@ -129,6 +140,8 @@ impl Module {
         self.pitch = PitchFollower::default();
         self.hz = 0.;
         self.sounding = false;
+        self.fallback.reset();
+        self.neutral = false;
         for ch in &mut self.state {
             for f in ch.iter_mut() {
                 f.reset();
@@ -143,6 +156,9 @@ impl Module {
     fn targets(&self) -> [f32; BANDS] {
         let s = &self.settings;
         let mut t = [0.; BANDS];
+        if self.neutral {
+            return t;
+        }
         for k in 1..=s.harmonics as usize {
             t[k - 1] = s.effective(k);
             t[HARMONICS + k - 1] = s.between;
@@ -187,6 +203,7 @@ impl Module {
             sample_rate: self.rate,
             input: *self.meter_in.levels(),
             output: *self.meter_out.levels(),
+            neutral: self.neutral,
             ..AnalyzerFrame::default()
         };
         if self.sounding && self.hz > 0. {
@@ -211,8 +228,9 @@ impl Tracked for Module {
         };
         self.pitch.event(self.settings.snap, e);
     }
-    fn process(&mut self, y: [f32; 2], sounding: bool) -> [f32; 2] {
-        self.sounding = sounding;
+    fn process(&mut self, y: [f32; 2], note: NoteState) -> [f32; 2] {
+        self.sounding = note.sure;
+        self.neutral = self.fallback.neutral(note);
         let first = self.hz == 0.;
         let (hz, jump) = self.pitch.step(self.hz_coef);
         let first = first && jump;
@@ -238,7 +256,7 @@ impl Tracked for Module {
             let wet = (self.mix * v + (1. - self.mix) * y[c]) * self.output;
             out[c] = wet * (1. - self.bypass) + y[c] * self.bypass;
         }
-        let hz = if sounding { self.hz } else { 0. };
+        let hz = if note.sure { self.hz } else { 0. };
         let (dry, wet) = if self.channels == 2 {
             (0.5 * (y[0] + y[1]), 0.5 * (out[0] + out[1]))
         } else {
@@ -286,7 +304,7 @@ impl Engine {
     fn set_tracker(&mut self, s: &Settings) {
         self.lookahead
             .tracker
-            .set(s.source == Source::Midi, s.gate, s.smooth > 0.);
+            .set(s.pitch.source(s.source.mode(), s.gate, s.smooth > 0.));
     }
     pub fn reset(&mut self) {
         self.lookahead.reset();

plugins/lathe/core/src/settings.rs

@@ -1,4 +1,5 @@
 //! Host-independent controls. Gains in dB, times in milliseconds.
+use common_dsp::tracker::{Pitch, PitchMode};
 use serde::{Deserialize, Serialize};
 
 /// Editable harmonics: the fundamental is harmonic 1.
@@ -13,12 +14,33 @@ pub enum Source {
     Audio,
     /// Notes come from MIDI note input.
     Midi,
+    /// Note starts are detected, the pitch is the set note: nothing is guessed.
+    Note,
+}
+impl Source {
+    pub fn mode(self) -> PitchMode {
+        match self {
+            Source::Audio => PitchMode::Audio,
+            Source::Midi => PitchMode::Midi,
+            Source::Note => PitchMode::Note,
+        }
+    }
+    pub fn from_mode(mode: PitchMode) -> Self {
+        match mode {
+            PitchMode::Audio => Source::Audio,
+            PitchMode::Midi => Source::Midi,
+            PitchMode::Note => Source::Note,
+        }
+    }
 }
 
 #[derive(Debug, Clone, Copy, Serialize, Deserialize, PartialEq)]
 #[serde(deny_unknown_fields)]
 pub struct Settings {
     pub source: Source,
+    /// Note mode's note, the key lock and Follow bends.
+    #[serde(default)]
+    pub pitch: Pitch,
     /// Gain per harmonic, index 0 = fundamental.
     pub gains: [f32; HARMONICS],
     /// dB per octave of harmonic number, added on top of `gains`. Harmonic 1 is the pivot.
@@ -45,6 +67,7 @@ impl Default for Settings {
     fn default() -> Self {
         Self {
             source: Source::Audio,
+            pitch: Pitch::default(),
             gains: [0.; HARMONICS],
             tilt: 0.,
             odd_even: 0.,
@@ -78,6 +101,7 @@ impl Settings {
         if !finite {
             return Err("non-finite setting");
         }
+        self.pitch.validate()?;
         let ok = self.gains.iter().all(|g| (GAIN_MIN..=GAIN_MAX).contains(g))
             && (-12.0..=12.).contains(&self.tilt)
             && (-12.0..=12.).contains(&self.odd_even)

plugins/lathe/core/tests/dsp.rs

@@ -137,3 +137,44 @@ fn settings_are_validated_and_serialise() {
     assert!(e.set_settings(bad).is_err());
     assert_eq!(e.settings(), s);
 }
+
+#[test]
+fn note_mode_cuts_the_set_notes_harmonics() {
+    let mut s = Settings::default();
+    s.gains[2] = -12.;
+    s.source = Source::Note;
+    s.pitch.note = 29;
+    let hz = 43.65;
+    let x = saw(hz, 1., 0.5);
+    let (mut e, l) = engine(s);
+    let y = render(&mut e, &x);
+    let a = harmonics(&x[..x.len() - l], hz);
+    let b = harmonics(&y[l..], hz);
+    assert!((b[2] - a[2] + 12.).abs() < 0.7, "{a:?} {b:?}");
+    assert!((b[1] - a[1]).abs() < 1.);
+}
+
+#[test]
+fn unsure_tracking_passes_the_audio_through() {
+    let mut s = Settings::default();
+    s.gains[0] = -12.;
+    s.gains[1] = -12.;
+    s.gains[2] = -12.;
+    let (mut e, l) = engine(s);
+    // A clear note, then noise detection cannot read.
+    let mut x = saw(55., 0.5, 0.5);
+    let mut seed = 7u32;
+    for _ in 0..RATE as usize {
+        seed ^= seed << 13;
+        seed ^= seed >> 17;
+        seed ^= seed << 5;
+        x.push((seed as f32 / u32::MAX as f32 - 0.5) * 0.5);
+    }
+    let y = render(&mut e, &x);
+    let tail = (RATE * 1.0) as usize;
+    let mut worst = 0f32;
+    for i in tail..x.len() {
+        worst = worst.max((y[i] - x[i - l]).abs());
+    }
+    assert!(worst < 1e-3, "{worst}");
+}

plugins/lathe/plugin/Cargo.lock

@@ -309,11 +309,23 @@ dependencies = [
 [[package]]
 name = "common-dsp"
 version = "0.1.0"
+dependencies = [
+ "serde",
+]
+
+[[package]]
+name = "common-params"
+version = "0.1.0"
+dependencies = [
+ "common-dsp",
+ "nih_plug",
+]
 
 [[package]]
 name = "common-ui"
 version = "0.1.0"
 dependencies = [
+ "common-dsp",
  "egui",
 ]
 
@@ -864,6 +876,7 @@ name = "lathe"
 version = "0.2.0"
 dependencies = [
  "clap-sys",
+ "common-params",
  "crossbeam-queue",
  "lathe-core",
  "lathe-ui",

plugins/lathe/plugin/Cargo.toml

@@ -13,6 +13,7 @@ crate-type = ["cdylib", "rlib"]
 nih_plug = { git = "https://github.com/robbert-vdh/nih-plug.git", rev = "de421011f41a6d10fc8c7a6084e4f4dee0143683", default-features = false }
 nih_plug_egui = { git = "https://github.com/robbert-vdh/nih-plug.git", rev = "de421011f41a6d10fc8c7a6084e4f4dee0143683" }
 lathe-core = { path = "../core" }
+common-params = { path = "../../common/params" }
 lathe-ui = { path = "../ui" }
 crossbeam-queue = "0.3"
 

plugins/lathe/plugin/src/params.rs

@@ -1,3 +1,4 @@
+use common_params::PitchParams;
 use lathe_core::{Settings, Source, HARMONICS};
 use nih_plug::prelude::*;
 use nih_plug_egui::EguiState;
@@ -10,6 +11,26 @@ pub enum SourceParam {
     #[id = "midi"]
     #[name = "MIDI"]
     Midi,
+    #[id = "note"]
+    Note,
+}
+impl From<SourceParam> for Source {
+    fn from(s: SourceParam) -> Self {
+        match s {
+            SourceParam::Audio => Source::Audio,
+            SourceParam::Midi => Source::Midi,
+            SourceParam::Note => Source::Note,
+        }
+    }
+}
+impl From<Source> for SourceParam {
+    fn from(s: Source) -> Self {
+        match s {
+            Source::Audio => SourceParam::Audio,
+            Source::Midi => SourceParam::Midi,
+            Source::Note => SourceParam::Note,
+        }
+    }
 }
 fn linear(name: &str, v: f32, min: f32, max: f32, unit: &'static str) -> FloatParam {
     FloatParam::new(name, v, FloatRange::Linear { min, max }).with_unit(unit)
@@ -26,6 +47,8 @@ pub struct LatheParams {
     pub gains: RwLock<[f32; HARMONICS]>,
     #[id = "source"]
     pub source: EnumParam<SourceParam>,
+    #[nested(group = "Pitch")]
+    pub pitch: PitchParams,
     #[id = "tilt"]
     pub tilt: FloatParam,
     #[id = "odd-even"]
@@ -56,6 +79,7 @@ impl Default for LatheParams {
             editor: EguiState::from_size(lathe_ui::WIDTH, lathe_ui::HEIGHT),
             gains: RwLock::new(d.gains),
             source: EnumParam::new("Pitch source", SourceParam::Audio),
+            pitch: PitchParams::default(),
             tilt: linear("Tilt", d.tilt, -12., 12., " dB/oct"),
             odd_even: linear("Odd/Even", d.odd_even, -12., 12., " dB"),
             between: linear("Between", d.between, -24., 12., " dB"),
@@ -83,10 +107,8 @@ impl LatheParams {
     pub fn settings(&self, last: &[f32; HARMONICS]) -> Settings {
         let gains = self.gains.try_read().map(|g| *g).unwrap_or(*last);
         Settings {
-            source: match self.source.value() {
-                SourceParam::Audio => Source::Audio,
-                SourceParam::Midi => Source::Midi,
-            },
+            source: self.source.value().into(),
+            pitch: self.pitch.pitch(),
             gains: gains.map(|g| {
                 if g.is_finite() {
                     g.clamp(lathe_core::GAIN_MIN, lathe_core::GAIN_MAX)
@@ -174,13 +196,10 @@ impl LatheParams {
             }
         }
         if new.source != old.source {
-            let v = match new.source {
-                Source::Audio => SourceParam::Audio,
-                Source::Midi => SourceParam::Midi,
-            };
             setter.begin_set_parameter(&self.source);
-            setter.set_parameter(&self.source, v);
+            setter.set_parameter(&self.source, new.source.into());
             setter.end_set_parameter(&self.source);
         }
+        self.pitch.apply(setter, &old.pitch, &new.pitch);
     }
 }

plugins/lathe/ui/src/lib.rs

@@ -277,13 +277,9 @@ pub fn show(ui: &mut egui::Ui, settings: &mut Settings, state: &mut State) {
             settings.bypass = !settings.bypass;
         }
         ui.separator();
-        for (source, label) in [(Source::Midi, "MIDI"), (Source::Audio, "AUDIO")] {
-            let r = ui.selectable_label(settings.source == source, RichText::new(label).size(13.));
-            if r.clicked() {
-                settings.source = source;
-            }
-        }
-        caption(ui, "PITCH FROM");
+        let mut mode = settings.source.mode();
+        pitch_from(ui, &mut mode, &mut settings.pitch);
+        settings.source = Source::from_mode(mode);
     });
     body(ui, settings, state);
     ui.separator();
@@ -326,6 +322,7 @@ fn note_panel(
     caption(ui, "NOTE");
     let (name, hz) = match frame.note {
         Some(n) if frame.hz > 0. => (common_dsp::note_name(n), format!("{:.1} Hz", frame.hz)),
+        _ if frame.neutral => ("?".into(), "unsure: passing through".into()),
         _ if frame.hz > 0. => ("—".into(), format!("holding {:.1} Hz", frame.hz)),
         _ => ("—".into(), "no note yet".into()),
     };
@@ -340,10 +337,7 @@ fn note_panel(
         RichText::new(format!(
             "{:.0} ms lookahead · {}",
             frame.latency as f32 / frame.sample_rate * 1000.,
-            match settings.source {
-                Source::Audio => "detecting pitch",
-                Source::Midi => "following MIDI",
-            }
+            pitch_status(settings.source.mode(), &settings.pitch)
         ))
         .size(12.)
         .color(MUTED),

plugins/patina/plugin/Cargo.lock

@@ -309,11 +309,15 @@ dependencies = [
 [[package]]
 name = "common-dsp"
 version = "0.1.0"
+dependencies = [
+ "serde",
+]
 
 [[package]]
 name = "common-ui"
 version = "0.1.0"
 dependencies = [
+ "common-dsp",
  "egui",
 ]
 

plugins/planish/core/src/lib.rs

@@ -34,6 +34,8 @@ pub const ATTACK_MS: [f32; BANDS] = [30., 15., 8., 4.];
 pub const RELEASE_MS: [f32; BANDS] = [200., 160., 120., 90.];
 /// Filter coefficients are recomputed this often, in samples.
 const RETUNE: usize = 16;
+/// A new note slides the band edges over about this long instead of snapping them.
+const EDGE_MS: f32 = 6.;
 const Q: f32 = std::f32::consts::FRAC_1_SQRT_2;
 const SILENT: f32 = -120.;
 
@@ -176,6 +178,9 @@ pub struct Engine {
     pitch: PitchFollower,
     hz: f32,
     hz_coef: f32,
+    edge_coef: f32,
+    /// The edges are sliding to a new note.
+    sliding: bool,
     countdown: usize,
     edges: [f32; BANDS - 1],
     coefs: Coefs,
@@ -226,6 +231,8 @@ impl Engine {
             pitch: PitchFollower::default(),
             hz: 0.,
             hz_coef: 1.,
+            edge_coef: coefficient(rate, EDGE_MS / 3.),
+            sliding: false,
             countdown: 0,
             edges: [0.; BANDS - 1],
             coefs: Coefs {
@@ -264,7 +271,7 @@ impl Engine {
     pub fn set_settings(&mut self, s: Settings) -> Result<(), &'static str> {
         s.validate()?;
         self.tracker
-            .set(s.source == Source::Midi, s.gate, s.smooth > 0.);
+            .set(s.pitch.source(s.source.mode(), s.gate, s.smooth > 0.));
         self.hz_coef = coefficient(self.rate, s.smooth / 3.);
         if s.time != self.settings.time || self.fresh {
             let scale = s.time * 0.01;
@@ -296,6 +303,7 @@ impl Engine {
         self.levels = [SILENT; BANDS];
         self.gains = [0.; BANDS];
         self.countdown = 0;
+        self.sliding = false;
         self.fresh = true;
     }
     pub fn note_on(&mut self, note: u8) {
@@ -346,9 +354,23 @@ impl Engine {
         self.delay_at = (self.delay_at + 1) % len;
         let y = self.delay[self.delay_at];
 
+        // Unsure tracking sends no events, so the edges hold the last sure note. A new note
+        // slides them instead of snapping, so the bands do not pump on note changes.
         let (hz, jump) = self.pitch.step(self.hz_coef);
-        self.hz = hz;
-        if jump || self.countdown == 0 {
+        let first = self.hz == 0.;
+        if jump && !first {
+            self.sliding = true;
+        }
+        if self.sliding {
+            self.hz += (hz - self.hz) * self.edge_coef;
+            if (hz - self.hz).abs() < 1e-3 * hz {
+                self.hz = hz;
+                self.sliding = false;
+            }
+        } else {
+            self.hz = hz;
+        }
+        if (jump && first) || self.countdown == 0 {
             self.retune();
             self.countdown = RETUNE;
         }
@@ -404,7 +426,7 @@ impl Engine {
             sample_rate: self.rate,
             ..AnalyzerFrame::default()
         };
-        if self.tracker.sounding() && self.hz > 0. {
+        if self.tracker.active() && self.hz > 0. {
             f.note = Some(hz_to_midi(self.hz).round().clamp(0., 127.) as u8);
         }
         f

plugins/planish/core/src/settings.rs

@@ -1,4 +1,5 @@
 //! Host-independent controls. Levels in dB, times in milliseconds, amounts in percent.
+use common_dsp::tracker::{Pitch, PitchMode};
 use serde::{Deserialize, Serialize};
 
 /// Bands: the fundamental, low harmonics, mid harmonics and the top.
@@ -15,12 +16,33 @@ pub enum Source {
     Audio,
     /// Notes come from MIDI note input.
     Midi,
+    /// Note starts are detected, the pitch is the set note: nothing is guessed.
+    Note,
+}
+impl Source {
+    pub fn mode(self) -> PitchMode {
+        match self {
+            Source::Audio => PitchMode::Audio,
+            Source::Midi => PitchMode::Midi,
+            Source::Note => PitchMode::Note,
+        }
+    }
+    pub fn from_mode(mode: PitchMode) -> Self {
+        match mode {
+            PitchMode::Audio => Source::Audio,
+            PitchMode::Midi => Source::Midi,
+            PitchMode::Note => Source::Note,
+        }
+    }
 }
 
 #[derive(Debug, Clone, Copy, Serialize, Deserialize, PartialEq)]
 #[serde(deny_unknown_fields)]
 pub struct Settings {
     pub source: Source,
+    /// Note mode's note, the key lock and Follow bends.
+    #[serde(default)]
+    pub pitch: Pitch,
     /// Highest harmonic in the bottom band. 1 keeps the fundamental on its own.
     pub low: u32,
     /// Highest harmonic in the second band.
@@ -54,6 +76,7 @@ impl Default for Settings {
     fn default() -> Self {
         Self {
             source: Source::Audio,
+            pitch: Pitch::default(),
             low: 1,
             mid: 4,
             high: 16,
@@ -73,6 +96,7 @@ impl Default for Settings {
 }
 impl Settings {
     pub fn validate(&self) -> Result<(), &'static str> {
+        self.pitch.validate()?;
         let finite = [
             self.depth,
             self.time,

plugins/planish/plugin/Cargo.lock

@@ -309,11 +309,23 @@ dependencies = [
 [[package]]
 name = "common-dsp"
 version = "0.1.0"
+dependencies = [
+ "serde",
+]
+
+[[package]]
+name = "common-params"
+version = "0.1.0"
+dependencies = [
+ "common-dsp",
+ "nih_plug",
+]
 
 [[package]]
 name = "common-ui"
 version = "0.1.0"
 dependencies = [
+ "common-dsp",
  "egui",
 ]
 
@@ -1443,6 +1455,7 @@ name = "planish"
 version = "0.1.0"
 dependencies = [
  "clap-sys",
+ "common-params",
  "crossbeam-queue",
  "nih_plug",
  "nih_plug_egui",

plugins/planish/plugin/Cargo.toml

@@ -13,6 +13,7 @@ crate-type = ["cdylib", "rlib"]
 nih_plug = { git = "https://github.com/robbert-vdh/nih-plug.git", rev = "de421011f41a6d10fc8c7a6084e4f4dee0143683", default-features = false }
 nih_plug_egui = { git = "https://github.com/robbert-vdh/nih-plug.git", rev = "de421011f41a6d10fc8c7a6084e4f4dee0143683" }
 planish-core = { path = "../core" }
+common-params = { path = "../../common/params" }
 planish-ui = { path = "../ui" }
 crossbeam-queue = "0.3"
 

plugins/planish/plugin/src/params.rs

@@ -1,3 +1,4 @@
+use common_params::PitchParams;
 use nih_plug::prelude::*;
 use nih_plug_egui::EguiState;
 use planish_core::{Settings, Source, BANDS, GAIN_MAX, GAIN_MIN, TOP_MAX};
@@ -10,6 +11,26 @@ pub enum SourceParam {
     #[id = "midi"]
     #[name = "MIDI"]
     Midi,
+    #[id = "note"]
+    Note,
+}
+impl From<SourceParam> for Source {
+    fn from(s: SourceParam) -> Self {
+        match s {
+            SourceParam::Audio => Source::Audio,
+            SourceParam::Midi => Source::Midi,
+            SourceParam::Note => Source::Note,
+        }
+    }
+}
+impl From<Source> for SourceParam {
+    fn from(s: Source) -> Self {
+        match s {
+            Source::Audio => SourceParam::Audio,
+            Source::Midi => SourceParam::Midi,
+            Source::Note => SourceParam::Note,
+        }
+    }
 }
 fn linear(name: &str, v: f32, min: f32, max: f32, unit: &'static str) -> FloatParam {
     FloatParam::new(name, v, FloatRange::Linear { min, max }).with_unit(unit)
@@ -26,6 +47,8 @@ pub struct PlanishParams {
     pub editor: Arc<EguiState>,
     #[id = "source"]
     pub source: EnumParam<SourceParam>,
+    #[nested(group = "Pitch")]
+    pub pitch: PitchParams,
     #[id = "depth"]
     pub depth: FloatParam,
     #[id = "time"]
@@ -68,6 +91,7 @@ impl Default for PlanishParams {
         Self {
             editor: EguiState::from_size(planish_ui::WIDTH, planish_ui::HEIGHT),
             source: EnumParam::new("Pitch source", SourceParam::Audio),
+            pitch: PitchParams::default(),
             depth: linear("Depth", d.depth, 0., 100., " %"),
             time: linear("Time", d.time, 10., 1000., " %"),
             upward: linear("Upward", d.upward, 0., 100., " %"),
@@ -92,10 +116,8 @@ impl PlanishParams {
     pub fn settings(&self) -> Settings {
         let gains = [&self.gain_1, &self.gain_2, &self.gain_3, &self.gain_4];
         Settings {
-            source: match self.source.value() {
-                SourceParam::Audio => Source::Audio,
-                SourceParam::Midi => Source::Midi,
-            },
+            source: self.source.value().into(),
+            pitch: self.pitch.pitch(),
             low: self.low.value() as u32,
             mid: self.mid.value() as u32,
             high: self.high.value() as u32,
@@ -180,13 +202,10 @@ impl PlanishParams {
             }
         }
         if new.source != old.source {
-            let v = match new.source {
-                Source::Audio => SourceParam::Audio,
-                Source::Midi => SourceParam::Midi,
-            };
             setter.begin_set_parameter(&self.source);
-            setter.set_parameter(&self.source, v);
+            setter.set_parameter(&self.source, new.source.into());
             setter.end_set_parameter(&self.source);
         }
+        self.pitch.apply(setter, &old.pitch, &new.pitch);
     }
 }

plugins/planish/ui/src/lib.rs

@@ -358,13 +358,9 @@ pub fn show(ui: &mut egui::Ui, settings: &mut Settings, state: &mut State) {
             settings.bypass = !settings.bypass;
         }
         ui.separator();
-        for (source, label) in [(Source::Midi, "MIDI"), (Source::Audio, "AUDIO")] {
-            let r = ui.selectable_label(settings.source == source, RichText::new(label).size(13.));
-            if r.clicked() {
-                settings.source = source;
-            }
-        }
-        caption(ui, "PITCH FROM");
+        let mut mode = settings.source.mode();
+        pitch_from(ui, &mut mode, &mut settings.pitch);
+        settings.source = Source::from_mode(mode);
     });
     ui.add_space(6.);
     let frame = state.analyzer;
@@ -418,10 +414,7 @@ fn note_panel(
         RichText::new(format!(
             "{:.0} ms lookahead · {}",
             frame.latency as f32 / frame.sample_rate * 1000.,
-            match settings.source {
-                Source::Audio => "detecting pitch",
-                Source::Midi => "following MIDI",
-            }
+            pitch_status(settings.source.mode(), &settings.pitch)
         ))
         .size(12.)
         .color(MUTED),

plugins/quench/plugin/Cargo.lock

@@ -309,11 +309,15 @@ dependencies = [
 [[package]]
 name = "common-dsp"
 version = "0.1.0"
+dependencies = [
+ "serde",
+]
 
 [[package]]
 name = "common-ui"
 version = "0.1.0"
 dependencies = [
+ "common-dsp",
  "egui",
 ]
 

plugins/temper/core/src/lib.rs

@@ -7,7 +7,7 @@ mod settings;
 use common_dsp::meter::{HarmonicMeter, HARMONICS};
 use common_dsp::oversample::Oversampler;
 use common_dsp::svf::{Svf, SvfCoef};
-use common_dsp::tracker::{Lookahead, NoteEvent, PitchFollower, Tracked, TrackerConfig};
+use common_dsp::tracker::{Lookahead, NoteEvent, NoteState, PitchFollower, Tracked, TrackerConfig};
 use common_dsp::{coefficient, db_to_gain, gain_to_db, hz_to_midi};
 pub use settings::{Curve, Settings, Source};
 
@@ -381,8 +381,10 @@ impl Tracked for Module {
         self.pitch.event(false, e);
         self.level.event(e);
     }
-    fn process(&mut self, y: [f32; 2], sounding: bool) -> [f32; 2] {
-        self.sounding = sounding;
+    fn process(&mut self, y: [f32; 2], note: NoteState) -> [f32; 2] {
+        // Unsure tracking sends no retune, so Floor, Push and Bright hold their last sure
+        // tuning; only the readout drops the note.
+        self.sounding = note.sure;
         self.run(y)
     }
 }
@@ -424,7 +426,7 @@ impl Engine {
     fn set_tracker(&mut self, s: &Settings) {
         self.lookahead
             .tracker
-            .set(s.source == Source::Midi, s.gate, true);
+            .set(s.pitch.source(s.source.mode(), s.gate, true));
     }
     pub fn reset(&mut self) {
         self.lookahead.reset();

plugins/temper/core/src/settings.rs

@@ -1,4 +1,5 @@
 //! Host-independent controls. Levels in dB, harmonic positions as multiples of the fundamental.
+use common_dsp::tracker::{Pitch, PitchMode};
 use serde::{Deserialize, Serialize};
 
 #[derive(Debug, Clone, Copy, Serialize, Deserialize, PartialEq, Eq, Default)]
@@ -8,6 +9,24 @@ pub enum Source {
     Audio,
     /// Notes come from MIDI note input.
     Midi,
+    /// Note starts are detected, the pitch is the set note: nothing is guessed.
+    Note,
+}
+impl Source {
+    pub fn mode(self) -> PitchMode {
+        match self {
+            Source::Audio => PitchMode::Audio,
+            Source::Midi => PitchMode::Midi,
+            Source::Note => PitchMode::Note,
+        }
+    }
+    pub fn from_mode(mode: PitchMode) -> Self {
+        match mode {
+            PitchMode::Audio => Source::Audio,
+            PitchMode::Midi => Source::Midi,
+            PitchMode::Note => Source::Note,
+        }
+    }
 }
 
 #[derive(Debug, Clone, Copy, Serialize, Deserialize, PartialEq, Eq, Default)]
@@ -58,6 +77,9 @@ impl Curve {
 #[serde(deny_unknown_fields)]
 pub struct Settings {
     pub source: Source,
+    /// Note mode's note, the key lock and Follow bends.
+    #[serde(default)]
+    pub pitch: Pitch,
     /// Gain into the shaper after level normalisation.
     pub drive: f32,
     pub curve: Curve,
@@ -85,6 +107,7 @@ impl Default for Settings {
     fn default() -> Self {
         Self {
             source: Source::Audio,
+            pitch: Pitch::default(),
             drive: 12.,
             curve: Curve::Soft,
             bias: 0.,
@@ -103,6 +126,7 @@ impl Default for Settings {
 }
 impl Settings {
     pub fn validate(&self) -> Result<(), &'static str> {
+        self.pitch.validate()?;
         let finite = [
             self.drive,
             self.bias,

plugins/temper/plugin/Cargo.lock

@@ -309,11 +309,23 @@ dependencies = [
 [[package]]
 name = "common-dsp"
 version = "0.1.0"
+dependencies = [
+ "serde",
+]
+
+[[package]]
+name = "common-params"
+version = "0.1.0"
+dependencies = [
+ "common-dsp",
+ "nih_plug",
+]
 
 [[package]]
 name = "common-ui"
 version = "0.1.0"
 dependencies = [
+ "common-dsp",
  "egui",
 ]
 
@@ -1737,6 +1749,7 @@ name = "temper"
 version = "0.2.0"
 dependencies = [
  "clap-sys",
+ "common-params",
  "crossbeam-queue",
  "nih_plug",
  "nih_plug_egui",

plugins/temper/plugin/Cargo.toml

@@ -13,6 +13,7 @@ crate-type = ["cdylib", "rlib"]
 nih_plug = { git = "https://github.com/robbert-vdh/nih-plug.git", rev = "de421011f41a6d10fc8c7a6084e4f4dee0143683", default-features = false }
 nih_plug_egui = { git = "https://github.com/robbert-vdh/nih-plug.git", rev = "de421011f41a6d10fc8c7a6084e4f4dee0143683" }
 temper-core = { path = "../core" }
+common-params = { path = "../../common/params" }
 temper-ui = { path = "../ui" }
 crossbeam-queue = "0.3"
 

plugins/temper/plugin/src/params.rs

@@ -1,3 +1,4 @@
+use common_params::PitchParams;
 use nih_plug::prelude::*;
 use nih_plug_egui::EguiState;
 use std::sync::Arc;
@@ -10,6 +11,26 @@ pub enum SourceParam {
     #[id = "midi"]
     #[name = "MIDI"]
     Midi,
+    #[id = "note"]
+    Note,
+}
+impl From<SourceParam> for Source {
+    fn from(s: SourceParam) -> Self {
+        match s {
+            SourceParam::Audio => Source::Audio,
+            SourceParam::Midi => Source::Midi,
+            SourceParam::Note => Source::Note,
+        }
+    }
+}
+impl From<Source> for SourceParam {
+    fn from(s: Source) -> Self {
+        match s {
+            Source::Audio => SourceParam::Audio,
+            Source::Midi => SourceParam::Midi,
+            Source::Note => SourceParam::Note,
+        }
+    }
 }
 #[derive(Enum, Debug, PartialEq, Eq, Clone, Copy)]
 pub enum CurveParam {
@@ -33,6 +54,8 @@ pub struct TemperParams {
     pub editor: Arc<EguiState>,
     #[id = "source"]
     pub source: EnumParam<SourceParam>,
+    #[nested(group = "Pitch")]
+    pub pitch: PitchParams,
     #[id = "curve"]
     pub curve: EnumParam<CurveParam>,
     #[id = "drive"]
@@ -66,6 +89,7 @@ impl Default for TemperParams {
         Self {
             editor: EguiState::from_size(temper_ui::WIDTH, temper_ui::HEIGHT),
             source: EnumParam::new("Pitch source", SourceParam::Audio),
+            pitch: PitchParams::default(),
             curve: EnumParam::new("Curve", CurveParam::Soft),
             drive: linear("Drive", d.drive, 0., 36., " dB"),
             bias: linear("Bias", d.bias, 0., 100., " %"),
@@ -108,10 +132,8 @@ impl TemperParams {
         let floor = self.floor.value();
         let bright = self.bright.value();
         Settings {
-            source: match self.source.value() {
-                SourceParam::Audio => Source::Audio,
-                SourceParam::Midi => Source::Midi,
-            },
+            source: self.source.value().into(),
+            pitch: self.pitch.pitch(),
             curve: curve_to(self.curve.value()),
             drive: self.drive.value(),
             bias: self.bias.value(),
@@ -195,13 +217,10 @@ impl TemperParams {
             setter.end_set_parameter(&self.curve);
         }
         if new.source != old.source {
-            let v = match new.source {
-                Source::Audio => SourceParam::Audio,
-                Source::Midi => SourceParam::Midi,
-            };
             setter.begin_set_parameter(&self.source);
-            setter.set_parameter(&self.source, v);
+            setter.set_parameter(&self.source, new.source.into());
             setter.end_set_parameter(&self.source);
         }
+        self.pitch.apply(setter, &old.pitch, &new.pitch);
     }
 }

plugins/temper/ui/src/lib.rs

@@ -235,13 +235,9 @@ pub fn show(ui: &mut egui::Ui, settings: &mut Settings, state: &mut State) {
         }
         toggles(ui, settings);
         ui.separator();
-        for (source, label) in [(Source::Midi, "MIDI"), (Source::Audio, "AUDIO")] {
-            let r = ui.selectable_label(settings.source == source, RichText::new(label).size(13.));
-            if r.clicked() {
-                settings.source = source;
-            }
-        }
-        caption(ui, "PITCH FROM");
+        let mut mode = settings.source.mode();
+        pitch_from(ui, &mut mode, &mut settings.pitch);
+        settings.source = Source::from_mode(mode);
     });
     body(ui, settings, state);
     ui.separator();
@@ -315,10 +311,7 @@ fn note_panel(ui: &mut egui::Ui, settings: &Settings, frame: &AnalyzerFrame) {
         RichText::new(format!(
             "{:.0} ms lookahead · {}",
             frame.latency as f32 / frame.sample_rate * 1000.,
-            match settings.source {
-                Source::Audio => "detecting pitch",
-                Source::Midi => "following MIDI",
-            }
+            pitch_status(settings.source.mode(), &settings.pitch)
         ))
         .size(12.)
         .color(MUTED),

plugins/weld/plugin/Cargo.lock

@@ -306,10 +306,18 @@ dependencies = [
  "memchr",
 ]
 
+[[package]]
+name = "common-dsp"
+version = "0.1.0"
+dependencies = [
+ "serde",
+]
+
 [[package]]
 name = "common-ui"
 version = "0.1.0"
 dependencies = [
+ "common-dsp",
  "egui",
 ]
 

tools/editor-check/Cargo.lock

@@ -123,11 +123,15 @@ checksum = "4e7648175b45a9a48536d676f68d918270699102aa8dab5496df06904c914600"
 [[package]]
 name = "common-dsp"
 version = "0.1.0"
+dependencies = [
+ "serde",
+]
 
 [[package]]
 name = "common-ui"
 version = "0.1.0"
 dependencies = [
+ "common-dsp",
  "egui",
 ]