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.

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),