feat: added v1 Meyda.js based chord detection feature

LICENSE

@@ -227,4 +227,38 @@ Copyright 2019 The MediaPipe Authors
 
 ---
 
+---
+
+### 8. Meyda
+
+Meyda is an audio feature extraction library used for chord detection.
+
+Original project: https://github.com/meyda/meyda
+
+```
+MIT License
+
+Copyright (c) 2014 Hugh A. Rawlinson, Nevo Segal, Jakub Fiala
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+THE SOFTWARE.
+```
+
+---
+
 Apache License Version 2.0, January 2004: http://www.apache.org/licenses/LICENSE-2.0

README.md

@@ -391,4 +391,4 @@ Licensed under the Apache License, Version 2.0, with additional terms (see `LICE
 - No patent applications using this software or assets
 - Attribution required when used in public/commercial products (“Powered by K.G.Studio”)  
 
-Third‑party notices (e.g., FluidR3_GM SoundFont, midi‑js‑soundfonts, VexFlow, prompt structure notes, Gemma 4 E4B, UVR-MDX-NET-Inst_HQ_3, and MediaPipe) are included in `LICENSE`.
+Third‑party notices (e.g., FluidR3_GM SoundFont, midi‑js‑soundfonts, VexFlow, prompt structure notes, Gemma 4 E4B, UVR-MDX-NET-Inst_HQ_3, MediaPipe, and Meyda) are included in `LICENSE`.

src/components/common/DialogProvider.css

@@ -146,6 +146,58 @@
   line-height: 1;
 }
 
+.dialog-chord-detection-form {
+  margin-top: 12px;
+  display: flex;
+  flex-direction: column;
+  gap: 16px;
+}
+
+.dialog-slider-group {
+  display: flex;
+  flex-direction: column;
+  gap: 8px;
+}
+
+.dialog-slider-header {
+  display: flex;
+  align-items: center;
+  justify-content: space-between;
+  gap: 12px;
+}
+
+.dialog-slider-label {
+  color: #d0d0d0;
+  font-size: 13px;
+  font-weight: 500;
+}
+
+.dialog-slider-value {
+  color: #8fbce0;
+  font-size: 12px;
+  font-family: 'Courier New', 'Monaco', 'Menlo', 'Ubuntu Mono', monospace;
+}
+
+.dialog-slider {
+  width: 100%;
+  accent-color: #5a9fd4;
+}
+
+.dialog-checkbox-row {
+  display: flex;
+  align-items: center;
+  gap: 10px;
+  color: #d0d0d0;
+  font-size: 13px;
+  cursor: pointer;
+}
+
+.dialog-checkbox-row input[type='checkbox'] {
+  width: 16px;
+  height: 16px;
+  accent-color: #5a9fd4;
+}
+
 .dialog-footer {
   display: flex;
   justify-content: flex-end;

src/components/common/DialogProvider.test.tsx

@@ -0,0 +1,86 @@
+import React from 'react';
+import { fireEvent, render, screen, waitFor } from '@testing-library/react';
+import { describe, expect, it } from 'vitest';
+import DialogProvider from './DialogProvider';
+import { showChordDetectionOptions } from '../../util/dialogUtil';
+
+function finishDialogCloseAnimation() {
+  const overlay = document.querySelector('.dialog-overlay');
+  if (overlay) {
+    fireEvent.animationEnd(overlay);
+  }
+}
+
+describe('DialogProvider chord detection dialog', () => {
+  it('opens the chord detection modal with the expected defaults and resolves cancel to null', async () => {
+    let resolved: unknown = 'pending';
+
+    render(
+      <DialogProvider>
+        <button
+          type="button"
+          onClick={async () => {
+            resolved = await showChordDetectionOptions('Tune chord detection settings before processing.', {
+              sensitivity: 50,
+              stability: 50,
+              noChordThreshold: 0,
+              enableSevenths: false,
+            });
+          }}
+        >
+          Open
+        </button>
+      </DialogProvider>,
+    );
+
+    fireEvent.click(screen.getByRole('button', { name: 'Open' }));
+
+    expect(screen.getByText('Chord Detection')).toBeInTheDocument();
+    expect(screen.getByLabelText('Sensitivity')).toHaveValue('50');
+    expect(screen.getByLabelText('Stability')).toHaveValue('50');
+    expect(screen.getByLabelText('No-Chord Threshold')).toHaveValue('0');
+    expect(screen.getByLabelText('Chord Detail: Enable sevenths')).not.toBeChecked();
+
+    fireEvent.click(screen.getByRole('button', { name: 'Cancel' }));
+    finishDialogCloseAnimation();
+
+    await waitFor(() => expect(resolved).toBeNull());
+  });
+
+  it('returns the adjusted chord detection options when confirmed', async () => {
+    let resolved: unknown = null;
+
+    render(
+      <DialogProvider>
+        <button
+          type="button"
+          onClick={async () => {
+            resolved = await showChordDetectionOptions('Tune chord detection settings before processing.', {
+              sensitivity: 50,
+              stability: 50,
+              noChordThreshold: 0,
+              enableSevenths: false,
+            });
+          }}
+        >
+          Open
+        </button>
+      </DialogProvider>,
+    );
+
+    fireEvent.click(screen.getByRole('button', { name: 'Open' }));
+    fireEvent.change(screen.getByLabelText('Sensitivity'), { target: { value: '62' } });
+    fireEvent.change(screen.getByLabelText('Stability'), { target: { value: '81' } });
+    fireEvent.change(screen.getByLabelText('No-Chord Threshold'), { target: { value: '24' } });
+    fireEvent.click(screen.getByLabelText('Chord Detail: Enable sevenths'));
+    fireEvent.click(screen.getByRole('button', { name: 'Detect' }));
+    finishDialogCloseAnimation();
+
+    await waitFor(() => expect(resolved).toEqual({
+      sensitivity: 62,
+      stability: 81,
+      noChordThreshold: 24,
+      enableSevenths: true,
+    }));
+  });
+});

src/components/common/DialogProvider.tsx

@@ -2,15 +2,22 @@ import React, { useState, useCallback, useRef } from 'react';
 import './DialogProvider.css';
 import { FaTimes } from 'react-icons/fa';
 import { registerDialogFns } from '../../util/dialogUtil';
-import type { ChoiceOption, ConfirmOptions, PromptOptions, TimeSigResult } from '../../util/dialogUtil';
+import type {
+  ChoiceOption,
+  ChordDetectionOptionsResult,
+  ConfirmOptions,
+  PromptOptions,
+  TimeSigResult,
+} from '../../util/dialogUtil';
 
 interface DialogInfo {
-  type: 'alert' | 'confirm' | 'prompt' | 'timesig' | 'choice';
+  type: 'alert' | 'confirm' | 'prompt' | 'timesig' | 'choice' | 'chord-detection';
   message: string;
   options?: ConfirmOptions | PromptOptions;
   defaultValue?: string;
   defaultTimeSig?: TimeSigResult;
   choices?: ChoiceOption[];
+  defaultChordDetectionOptions?: ChordDetectionOptionsResult;
 }
 
 const DialogProvider: React.FC<{ children: React.ReactNode }> = ({ children }) => {
@@ -19,6 +26,12 @@ const DialogProvider: React.FC<{ children: React.ReactNode }> = ({ children }) =
   const [inputValue, setInputValue] = useState('');
   const [timeSigNumerator, setTimeSigNumerator] = useState('');
   const [timeSigDenominator, setTimeSigDenominator] = useState('');
+  const [chordDetectionOptions, setChordDetectionOptions] = useState<ChordDetectionOptionsResult>({
+    sensitivity: 50,
+    stability: 50,
+    noChordThreshold: 0,
+    enableSevenths: false,
+  });
   // eslint-disable-next-line @typescript-eslint/no-explicit-any
   const resolveRef = useRef<((value: any) => void) | null>(null);
   const pendingValueRef = useRef<unknown>(undefined);
@@ -61,6 +74,22 @@ const DialogProvider: React.FC<{ children: React.ReactNode }> = ({ children }) =
     });
   }, []);
 
+  const openChordDetectionOptions = useCallback((
+    message: string,
+    defaultValue?: ChordDetectionOptionsResult,
+  ): Promise<ChordDetectionOptionsResult | null> => {
+    return new Promise<ChordDetectionOptionsResult | null>((resolve) => {
+      resolveRef.current = resolve;
+      setChordDetectionOptions(defaultValue ?? {
+        sensitivity: 50,
+        stability: 50,
+        noChordThreshold: 0,
+        enableSevenths: false,
+      });
+      setDialog({ type: 'chord-detection', message, defaultChordDetectionOptions: defaultValue });
+    });
+  }, []);
+
   const close = useCallback((value: unknown) => {
     pendingValueRef.current = value;
     setIsClosing(true);
@@ -74,6 +103,12 @@ const DialogProvider: React.FC<{ children: React.ReactNode }> = ({ children }) =
     setInputValue('');
     setTimeSigNumerator('');
     setTimeSigDenominator('');
+    setChordDetectionOptions({
+      sensitivity: 50,
+      stability: 50,
+      noChordThreshold: 0,
+      enableSevenths: false,
+    });
     if (resolveRef.current) {
       resolveRef.current(pendingValueRef.current);
       resolveRef.current = null;
@@ -85,7 +120,7 @@ const DialogProvider: React.FC<{ children: React.ReactNode }> = ({ children }) =
   const registered = useRef(false);
   if (!registered.current) {
     registered.current = true;
-    registerDialogFns(openAlert, openConfirm, openPrompt, openTimeSig, openChoice);
+    registerDialogFns(openAlert, openConfirm, openPrompt, openTimeSig, openChoice, openChordDetectionOptions);
   }
 
   if (!dialog) {
@@ -96,9 +131,18 @@ const DialogProvider: React.FC<{ children: React.ReactNode }> = ({ children }) =
   const isPrompt = dialog.type === 'prompt';
   const isTimeSig = dialog.type === 'timesig';
   const isChoice = dialog.type === 'choice';
+  const isChordDetection = dialog.type === 'chord-detection';
   const promptOptions = isPrompt ? (dialog.options as PromptOptions | undefined) : undefined;
 
-  const title = isAlert ? 'Notice' : isTimeSig ? 'Time Signature' : isPrompt ? 'Input' : 'Confirm';
+  const title = isAlert
+    ? 'Notice'
+    : isTimeSig
+      ? 'Time Signature'
+      : isChordDetection
+        ? 'Chord Detection'
+        : isPrompt
+          ? 'Input'
+          : 'Confirm';
 
   const handleOverlayMouseDown = (e: React.MouseEvent) => {
     mouseDownOnOverlay.current = e.target === e.currentTarget;
@@ -106,11 +150,11 @@ const DialogProvider: React.FC<{ children: React.ReactNode }> = ({ children }) =
 
   const handleOverlayClick = (e: React.MouseEvent) => {
     if (e.target === e.currentTarget && mouseDownOnOverlay.current) {
-      close(isAlert ? undefined : (isPrompt || isTimeSig || isChoice) ? null : false);
+      close(isAlert ? undefined : (isPrompt || isTimeSig || isChoice || isChordDetection) ? null : false);
     }
   };
 
-  const handleCancel = () => close(isAlert ? undefined : (isPrompt || isTimeSig || isChoice) ? null : false);
+  const handleCancel = () => close(isAlert ? undefined : (isPrompt || isTimeSig || isChoice || isChordDetection) ? null : false);
 
   const handleConfirm = () => {
     if (isAlert) { close(undefined); return; }
@@ -119,9 +163,20 @@ const DialogProvider: React.FC<{ children: React.ReactNode }> = ({ children }) =
       close({ numerator: Number(timeSigNumerator), denominator: Number(timeSigDenominator) });
       return;
     }
+    if (isChordDetection) {
+      close(chordDetectionOptions);
+      return;
+    }
     close(true);
   };
 
+  const updateChordDetectionOption = <K extends keyof ChordDetectionOptionsResult>(
+    key: K,
+    value: ChordDetectionOptionsResult[K],
+  ) => {
+    setChordDetectionOptions(current => ({ ...current, [key]: value }));
+  };
+
   return (
     <>
       {children}
@@ -181,6 +236,68 @@ const DialogProvider: React.FC<{ children: React.ReactNode }> = ({ children }) =
                 />
               </div>
             )}
+            {isChordDetection && (
+              <div className="dialog-chord-detection-form">
+                <div className="dialog-slider-group">
+                  <div className="dialog-slider-header">
+                    <label className="dialog-slider-label" htmlFor="dialog-chord-sensitivity">Sensitivity</label>
+                    <span className="dialog-slider-value">{chordDetectionOptions.sensitivity}</span>
+                  </div>
+                  <input
+                    id="dialog-chord-sensitivity"
+                    className="dialog-slider"
+                    type="range"
+                    min={0}
+                    max={100}
+                    step={1}
+                    value={chordDetectionOptions.sensitivity}
+                    onChange={(e) => updateChordDetectionOption('sensitivity', Number(e.target.value))}
+                    autoFocus
+                  />
+                </div>
+                <div className="dialog-slider-group">
+                  <div className="dialog-slider-header">
+                    <label className="dialog-slider-label" htmlFor="dialog-chord-stability">Stability</label>
+                    <span className="dialog-slider-value">{chordDetectionOptions.stability}</span>
+                  </div>
+                  <input
+                    id="dialog-chord-stability"
+                    className="dialog-slider"
+                    type="range"
+                    min={0}
+                    max={100}
+                    step={1}
+                    value={chordDetectionOptions.stability}
+                    onChange={(e) => updateChordDetectionOption('stability', Number(e.target.value))}
+                  />
+                </div>
+                <div className="dialog-slider-group">
+                  <div className="dialog-slider-header">
+                    <label className="dialog-slider-label" htmlFor="dialog-chord-no-chord-threshold">No-Chord Threshold</label>
+                    <span className="dialog-slider-value">{chordDetectionOptions.noChordThreshold}</span>
+                  </div>
+                  <input
+                    id="dialog-chord-no-chord-threshold"
+                    className="dialog-slider"
+                    type="range"
+                    min={0}
+                    max={100}
+                    step={1}
+                    value={chordDetectionOptions.noChordThreshold}
+                    onChange={(e) => updateChordDetectionOption('noChordThreshold', Number(e.target.value))}
+                  />
+                </div>
+                <label className="dialog-checkbox-row" htmlFor="dialog-enable-sevenths">
+                  <input
+                    id="dialog-enable-sevenths"
+                    type="checkbox"
+                    checked={chordDetectionOptions.enableSevenths}
+                    onChange={(e) => updateChordDetectionOption('enableSevenths', e.target.checked)}
+                  />
+                  <span>Chord Detail: Enable sevenths</span>
+                </label>
+              </div>
+            )}
           </div>
           <div className="dialog-footer">
             {!isAlert && (
@@ -206,9 +323,9 @@ const DialogProvider: React.FC<{ children: React.ReactNode }> = ({ children }) =
               <button
                 className="dialog-btn dialog-btn-primary"
                 onClick={handleConfirm}
-                autoFocus={!isPrompt && !isTimeSig}
+                autoFocus={!isPrompt && !isTimeSig && !isChordDetection}
               >
-                {isAlert ? 'OK' : ((dialog.options as ConfirmOptions | PromptOptions | undefined)?.confirmLabel ?? (isPrompt || isTimeSig ? 'OK' : 'Yes'))}
+                {isAlert ? 'OK' : ((dialog.options as ConfirmOptions | PromptOptions | undefined)?.confirmLabel ?? (isPrompt || isTimeSig ? 'OK' : isChordDetection ? 'Detect' : 'Yes'))}
               </button>
             )}
           </div>

src/components/common/index.ts

@@ -6,5 +6,5 @@ export { default as OpenProjectModal } from './OpenProjectModal';
 export { default as DialogProvider } from './DialogProvider';
 export { default as TrackCreateDialog } from './TrackCreateDialog';
 export { default as FloatingPopup } from './FloatingPopup';
-export { showAlert, showConfirm, showPrompt, showTimeSigPrompt } from '../../util/dialogUtil';
+export { showAlert, showChordDetectionOptions, showConfirm, showPrompt, showTimeSigPrompt } from '../../util/dialogUtil';
-export type { ConfirmOptions, PromptOptions, TimeSigResult } from '../../util/dialogUtil';
+export type { ChordDetectionOptionsResult, ConfirmOptions, PromptOptions, TimeSigResult } from '../../util/dialogUtil';

src/components/piano-roll/PianoRoll.tsx

@@ -20,14 +20,16 @@ import { ReplaceChordRegionsInRangeCommand, UpdateRegionCommand } from '../../co
 import { KGAudioInterface } from '../../core/audio-interface/KGAudioInterface';
 import { KGAudioFileStorage } from '../../core/io/KGAudioFileStorage';
 import { getSuitableChords, noteNameToPitchClass } from '../../util/scaleUtil';
-import { showAlert } from '../../util/dialogUtil';
+import { showAlert, showChordDetectionOptions } from '../../util/dialogUtil';
 import {
   normalizeSpectrogramHeightResolution,
   type SpectrogramHeightResolution,
 } from '../../util/spectrogramUtil';
 import {
+  DEFAULT_AUDIO_CHORD_DETECTION_OPTIONS,
   buildAudioChordWindowsForRegion,
   type AudioChordDetectionRequest,
+  type AudioChordDetectionOptions,
   type DetectedAudioChord,
 } from '../../util/audioChordDetection';
 import type { AudioChordDetectionWorkerMessage } from '../../workers/audioChordDetectionWorker';
@@ -460,6 +462,14 @@ const PianoRoll: React.FC<PianoRollProps> = ({
       return;
     }
 
+    const detectionOptions = await showChordDetectionOptions(
+      'Tune chord detection settings before processing.',
+      DEFAULT_AUDIO_CHORD_DETECTION_OPTIONS,
+    );
+    if (!detectionOptions) {
+      return;
+    }
+
     setIsDetectingChords(true);
     setDetectChordProgressPercent(0);
     let worker: Worker | null = null;
@@ -485,6 +495,7 @@ const PianoRoll: React.FC<PianoRollProps> = ({
         sampleRate: audioBuffer.sampleRate,
         clipStartOffsetSeconds: audioRegion.getClipStartOffsetSeconds(),
         windows,
+        options: detectionOptions as AudioChordDetectionOptions,
       };
 
       const detectedChords = await new Promise<DetectedAudioChord[]>((resolve, reject) => {

src/test/integration/audio-chord-detection.integration.test.ts

@@ -1,7 +1,10 @@
 import { execFileSync, spawnSync } from 'node:child_process';
 import path from 'node:path';
 import { describe, expect, it } from 'vitest';
-import { detectChordsFromAudio } from '../../util/audioChordDetectionCore';
+import {
+  DEFAULT_AUDIO_CHORD_DETECTION_OPTIONS,
+  detectChordsFromAudio,
+} from '../../util/audioChordDetectionCore';
 
 const FIXTURE_PATH = path.resolve(process.cwd(), 'public/test-data/chord-progression-01.mp3');
 const BAR_DURATION_SECONDS = 2;
@@ -48,7 +51,7 @@ function decodeMp3ToMonoPcm(path: string): { sampleRate: number; pcm: Float32Arr
 }
 
 describe('audio chord detection fixture', () => {
-  runIfFfmpeg('detects the expected bar-locked progression from the mp3 fixture', () => {
+  runIfFfmpeg('detects the expected bar-locked progression from the mp3 fixture with triads only', () => {
     const { sampleRate, pcm } = decodeMp3ToMonoPcm(FIXTURE_PATH);
     const windows = Array.from({ length: 9 }, (_, barIndex) => ({
       barIndex,
@@ -63,6 +66,7 @@ describe('audio chord detection fixture', () => {
       sampleRate,
       clipStartOffsetSeconds: 0,
       windows,
+      options: DEFAULT_AUDIO_CHORD_DETECTION_OPTIONS,
     });
 
     expect(results.map(result => result.symbol)).toEqual([
@@ -77,4 +81,38 @@ describe('audio chord detection fixture', () => {
       'N',
     ]);
   });
+
+  runIfFfmpeg('detects the expected bar-locked progression from the mp3 fixture with sevenths enabled', () => {
+    const { sampleRate, pcm } = decodeMp3ToMonoPcm(FIXTURE_PATH);
+    const windows = Array.from({ length: 9 }, (_, barIndex) => ({
+      barIndex,
+      startBeat: barIndex * 4,
+      endBeat: (barIndex + 1) * 4,
+      startSeconds: barIndex * BAR_DURATION_SECONDS,
+      endSeconds: (barIndex + 1) * BAR_DURATION_SECONDS,
+    }));
+
+    const results = detectChordsFromAudio({
+      pcm,
+      sampleRate,
+      clipStartOffsetSeconds: 0,
+      windows,
+      options: {
+        ...DEFAULT_AUDIO_CHORD_DETECTION_OPTIONS,
+        enableSevenths: true,
+      },
+    });
+
+    expect(results.map(result => result.symbol)).toEqual([
+      'Am',
+      'F',
+      'Dm',
+      'E7',
+      'Am',
+      'C',
+      'Dm',
+      'E7',
+      'N',
+    ]);
+  });
 });

src/util/audioChordDetection.test.ts

@@ -1,5 +1,10 @@
 import { describe, expect, it } from 'vitest';
-import { detectChordsFromAudio, type AudioChordDetectionRequest } from './audioChordDetectionCore';
+import {
+  DEFAULT_AUDIO_CHORD_DETECTION_OPTIONS,
+  detectChordsFromAudio,
+  type AudioChordDetectionOptions,
+  type AudioChordDetectionRequest,
+} from './audioChordDetectionCore';
 
 const SAMPLE_RATE = 44100;
 
@@ -19,12 +24,20 @@ function createSineChordPcm(frequencies: number[], durationSeconds: number): Flo
   return pcm;
 }
 
-function createRequest(windows: AudioChordDetectionRequest['windows'], pcm: Float32Array): AudioChordDetectionRequest {
+function createRequest(
+  windows: AudioChordDetectionRequest['windows'],
+  pcm: Float32Array,
+  options?: Partial<AudioChordDetectionOptions>,
+): AudioChordDetectionRequest {
   return {
     pcm,
     sampleRate: SAMPLE_RATE,
     clipStartOffsetSeconds: 0,
     windows,
+    options: {
+      ...DEFAULT_AUDIO_CHORD_DETECTION_OPTIONS,
+      ...options,
+    },
   };
 }
 
@@ -72,4 +85,62 @@ describe('audio chord detection', () => {
 
     expect(results.map(result => result.symbol)).toEqual(['Am', 'Am']);
   });
+
+  it('uses default options to preserve current triad-first behavior', () => {
+    const pcm = createSineChordPcm([329.63, 415.3, 493.88, 587.33], 2);
+    const [result] = detectChordsFromAudio(createRequest([
+      { barIndex: 0, startBeat: 0, endBeat: 4, startSeconds: 0, endSeconds: 2 },
+    ], pcm));
+
+    expect(result.symbol).toBe('E');
+  });
+
+  it('can emit a seventh label when chord detail is enabled', () => {
+    const pcm = createSineChordPcm([329.63, 415.3, 493.88, 587.33], 2);
+    const [result] = detectChordsFromAudio(createRequest([
+      { barIndex: 0, startBeat: 0, endBeat: 4, startSeconds: 0, endSeconds: 2 },
+    ], pcm, { enableSevenths: true }));
+
+    expect(result.symbol).toBe('E7');
+  });
+
+  it('can suppress a weak bar when no-chord threshold is increased', () => {
+    const pcm = createSineChordPcm([261.63, 329.63, 392.0], 2);
+    for (let sampleIndex = 0; sampleIndex < pcm.length; sampleIndex++) {
+      pcm[sampleIndex] *= 0.04;
+    }
+
+    const [result] = detectChordsFromAudio(createRequest([
+      { barIndex: 0, startBeat: 0, endBeat: 4, startSeconds: 0, endSeconds: 2 },
+    ], pcm, { noChordThreshold: 95 }));
+
+    expect(result.symbol).toBe('N');
+  });
+
+  it('changes smoothing behavior when stability is lowered', () => {
+    const barA = createSineChordPcm([220.0, 261.63, 329.63], 2);
+    const barB = createSineChordPcm([261.63, 329.63], 2);
+    for (let sampleIndex = 0; sampleIndex < barB.length; sampleIndex++) {
+      barB[sampleIndex] *= 0.3;
+    }
+    const barC = createSineChordPcm([220.0, 261.63, 329.63], 2);
+    const pcm = new Float32Array(barA.length + barB.length + barC.length);
+    pcm.set(barA, 0);
+    pcm.set(barB, barA.length);
+    pcm.set(barC, barA.length + barB.length);
+
+    const stableResults = detectChordsFromAudio(createRequest([
+      { barIndex: 0, startBeat: 0, endBeat: 4, startSeconds: 0, endSeconds: 2 },
+      { barIndex: 1, startBeat: 4, endBeat: 8, startSeconds: 2, endSeconds: 4 },
+      { barIndex: 2, startBeat: 8, endBeat: 12, startSeconds: 4, endSeconds: 6 },
+    ], pcm, { stability: 100 }));
+    const unstableResults = detectChordsFromAudio(createRequest([
+      { barIndex: 0, startBeat: 0, endBeat: 4, startSeconds: 0, endSeconds: 2 },
+      { barIndex: 1, startBeat: 4, endBeat: 8, startSeconds: 2, endSeconds: 4 },
+      { barIndex: 2, startBeat: 8, endBeat: 12, startSeconds: 4, endSeconds: 6 },
+    ], pcm, { stability: 0 }));
+
+    expect(stableResults[1].symbol).toBe('Am');
+    expect(unstableResults[1].symbol).not.toBe('Am');
+  });
 });

src/util/audioChordDetection.ts

@@ -3,8 +3,10 @@ import { KGAudioRegion } from '../core/region/KGAudioRegion';
 import { beatRangeToSeconds, getAudioRegionDisplayLengthBeats } from './globalTrackUtil';
 
 export {
+  DEFAULT_AUDIO_CHORD_DETECTION_OPTIONS,
   detectChordsFromAudio,
   type AudioChordDetectionRequest,
+  type AudioChordDetectionOptions,
   type AudioChordWindow,
   type DetectedAudioChord,
 } from './audioChordDetectionCore';

src/util/audioChordDetectionCore.ts

@@ -22,6 +22,7 @@ export interface AudioChordDetectionRequest {
   sampleRate: number;
   clipStartOffsetSeconds: number;
   windows: AudioChordWindow[];
+  options: AudioChordDetectionOptions;
 }
 
 export interface DetectedAudioChord {
@@ -39,11 +40,30 @@ export interface AudioChordDetectionProgress {
   percent: number;
 }
 
+export interface AudioChordDetectionOptions {
+  sensitivity: number;
+  stability: number;
+  noChordThreshold: number;
+  enableSevenths: boolean;
+}
+
 interface ScoredChord {
   symbol: string;
   score: number;
 }
 
+interface TriadCandidate extends ScoredChord {
+  root: number;
+  quality: 'major' | 'minor';
+}
+
+export const DEFAULT_AUDIO_CHORD_DETECTION_OPTIONS: AudioChordDetectionOptions = {
+  sensitivity: 50,
+  stability: 50,
+  noChordThreshold: 0,
+  enableSevenths: false,
+};
+
 const HANN_WINDOW = (() => {
   const window = new Float32Array(FFT_SIZE);
   for (let i = 0; i < FFT_SIZE; i++) {
@@ -56,13 +76,50 @@ function clamp(value: number, min: number, max: number): number {
   return Math.max(min, Math.min(max, value));
 }
 
+function parseChordSymbol(symbol: string): { rootIndex: number; quality: 'major' | 'minor' | 'other' } | null {
+  if (!symbol || symbol === 'N') {
+    return null;
+  }
+
+  const rootName = symbol.startsWith('C#') || symbol.startsWith('D#') || symbol.startsWith('F#') || symbol.startsWith('G#') || symbol.startsWith('A#')
+    ? symbol.slice(0, 2)
+    : symbol.slice(0, 1);
+  const rootIndex = ROOT_NAMES.indexOf(rootName as typeof ROOT_NAMES[number]);
+  if (rootIndex < 0) {
+    return null;
+  }
+
+  if (symbol === `${rootName}m`) {
+    return { rootIndex, quality: 'minor' };
+  }
+
+  if (symbol === rootName) {
+    return { rootIndex, quality: 'major' };
+  }
+
+  return { rootIndex, quality: 'other' };
+}
+
 function cloneWindow(window: AudioChordWindow): AudioChordWindow {
   return { ...window };
 }
 
-function buildTriadCandidates(chroma: Float64Array): { best: ScoredChord; second: ScoredChord } {
+function buildChordCandidates(
-  let best: ScoredChord = { symbol: 'N', score: Number.NEGATIVE_INFINITY };
+  chroma: Float64Array,
-  let second: ScoredChord = { symbol: 'N', score: Number.NEGATIVE_INFINITY };
+  options: AudioChordDetectionOptions,
+): { best: ScoredChord; second: ScoredChord } {
+  let bestTriad: TriadCandidate = {
+    symbol: 'N',
+    score: Number.NEGATIVE_INFINITY,
+    root: 0,
+    quality: 'major',
+  };
+  let secondTriad: TriadCandidate = {
+    symbol: 'N',
+    score: Number.NEGATIVE_INFINITY,
+    root: 0,
+    quality: 'major',
+  };
 
   for (let root = 0; root < ROOT_NAMES.length; root++) {
     const rootEnergy = chroma[root];
@@ -74,12 +131,61 @@ function buildTriadCandidates(chroma: Float64Array): { best: ScoredChord; second
     const majorScore = (rootEnergy * 1.2) + (majorThird * 1.0) + (fifth * 0.8) - (outsideEnergy * 0.35) - (minorThird * 0.5);
     const minorScore = (rootEnergy * 1.2) + (minorThird * 1.0) + (fifth * 0.8) - (outsideEnergy * 0.35) - (majorThird * 0.5);
 
-    const candidates: ScoredChord[] = [
+    const triadCandidates: TriadCandidate[] = [
-      { symbol: ROOT_NAMES[root], score: majorScore },
+      { symbol: ROOT_NAMES[root], score: majorScore, root, quality: 'major' },
-      { symbol: `${ROOT_NAMES[root]}m`, score: minorScore },
+      { symbol: `${ROOT_NAMES[root]}m`, score: minorScore, root, quality: 'minor' },
     ];
 
-    for (const candidate of candidates) {
+    for (const candidate of triadCandidates) {
+      if (candidate.score > bestTriad.score) {
+        secondTriad = bestTriad;
+        bestTriad = candidate;
+      } else if (candidate.score > secondTriad.score) {
+        secondTriad = candidate;
+      }
+    }
+  }
+
+  let best: ScoredChord = { symbol: bestTriad.symbol, score: bestTriad.score };
+  let second: ScoredChord = { symbol: secondTriad.symbol, score: secondTriad.score };
+
+  if (!options.enableSevenths || bestTriad.symbol === 'N') {
+    return { best, second };
+  }
+
+  const rootEnergy = chroma[bestTriad.root];
+  const minorSeventh = chroma[(bestTriad.root + 10) % 12];
+  const majorSeventh = chroma[(bestTriad.root + 11) % 12];
+  const seventhCandidates: ScoredChord[] = [];
+
+  if (bestTriad.quality === 'major') {
+    const dominantSeventhBonus = Math.max(0, minorSeventh - 0.06) * 2.5;
+    const majorSeventhBonus = Math.max(0, majorSeventh - 0.2) * 1.65;
+
+    if (dominantSeventhBonus > 0 && minorSeventh >= rootEnergy * 0.2) {
+      seventhCandidates.push({
+        symbol: `${ROOT_NAMES[bestTriad.root]}7`,
+        score: bestTriad.score + dominantSeventhBonus - (majorSeventh * 0.18) - 0.02,
+      });
+    }
+
+    if (majorSeventhBonus > 0 && majorSeventh >= rootEnergy * 0.42) {
+      seventhCandidates.push({
+        symbol: `${ROOT_NAMES[bestTriad.root]}maj7`,
+        score: bestTriad.score + majorSeventhBonus - (minorSeventh * 0.2) - 0.04,
+      });
+    }
+  } else {
+    const minorSeventhBonus = Math.max(0, minorSeventh - 0.2) * 1.65;
+    if (minorSeventhBonus > 0 && minorSeventh >= rootEnergy * 0.42) {
+      seventhCandidates.push({
+        symbol: `${ROOT_NAMES[bestTriad.root]}m7`,
+        score: bestTriad.score + minorSeventhBonus - (majorSeventh * 0.14) - 0.04,
+      });
+    }
+  }
+
+  for (const candidate of seventhCandidates) {
     if (candidate.score > best.score) {
       second = best;
       best = candidate;
@@ -87,7 +193,6 @@ function buildTriadCandidates(chroma: Float64Array): { best: ScoredChord; second
       second = candidate;
     }
   }
-  }
 
   return { best, second };
 }
@@ -97,6 +202,7 @@ function analyzeChordWindow(
   sampleRate: number,
   startSeconds: number,
   endSeconds: number,
+  options: AudioChordDetectionOptions,
 ): { symbol: string; confidence: number; rms: number } {
   const startSample = Math.max(0, Math.floor(startSeconds * sampleRate));
   const endSample = Math.min(pcm.length, Math.ceil(endSeconds * sampleRate));
@@ -171,7 +277,7 @@ function analyzeChordWindow(
     chroma[i] /= chromaTotal;
   }
 
-  const { best, second } = buildTriadCandidates(chroma);
+  const { best, second } = buildChordCandidates(chroma, options);
   return {
     symbol: best.symbol,
     confidence: clamp(best.score - second.score + (best.score * 0.2), 0, 1),
@@ -179,12 +285,18 @@ function analyzeChordWindow(
   };
 }
 
-function smoothDetectedChords(results: DetectedAudioChord[]): DetectedAudioChord[] {
+function smoothDetectedChords(
+  results: DetectedAudioChord[],
+  options: AudioChordDetectionOptions,
+): DetectedAudioChord[] {
   if (results.length < 3) {
     return results.map(result => ({ ...result }));
   }
 
   const smoothed = results.map(result => ({ ...result }));
+  const stability = clamp(options.stability, 0, 100);
+  const smoothingThreshold = 0.6 + (0.7 * (stability / 100));
+  const inheritedConfidenceFloor = 0.45 + (0.6 * (stability / 100));
   for (let i = 1; i < smoothed.length - 1; i++) {
     const previous = smoothed[i - 1];
     const current = smoothed[i];
@@ -194,9 +306,9 @@ function smoothDetectedChords(results: DetectedAudioChord[]): DetectedAudioChord
     }
     if (previous.symbol === next.symbol && previous.symbol !== 'N' && current.symbol !== previous.symbol) {
       const surroundingConfidence = Math.max(previous.confidence, next.confidence);
-      if (current.confidence < surroundingConfidence * 0.85) {
+      if (current.confidence < surroundingConfidence * smoothingThreshold) {
         current.symbol = previous.symbol;
-        current.confidence = Math.max(current.confidence, surroundingConfidence * 0.75);
+        current.confidence = Math.max(current.confidence, surroundingConfidence * inheritedConfidenceFloor);
       }
     }
   }
@@ -204,6 +316,45 @@ function smoothDetectedChords(results: DetectedAudioChord[]): DetectedAudioChord
   return smoothed;
 }
 
+function applySeventhContextPromotion(results: DetectedAudioChord[], options: AudioChordDetectionOptions): DetectedAudioChord[] {
+  if (!options.enableSevenths || results.length < 2) {
+    return results.map(result => ({ ...result }));
+  }
+
+  const promoted = results.map(result => ({ ...result }));
+  for (let i = 0; i < promoted.length - 1; i++) {
+    const current = promoted[i];
+    const next = promoted[i + 1];
+    const previous = i > 0 ? promoted[i - 1] : null;
+    const currentChord = parseChordSymbol(current.symbol);
+    const nextChord = parseChordSymbol(next.symbol);
+    const previousChord = previous ? parseChordSymbol(previous.symbol) : null;
+
+    if (!currentChord) {
+      continue;
+    }
+
+    const resolvesToMinorTonic = nextChord
+      && currentChord.quality === 'major'
+      && nextChord.quality === 'minor'
+      && current.confidence >= 0.3
+      && ((nextChord.rootIndex - currentChord.rootIndex + 12) % 12) === 5;
+
+    const endsAfterMinorPredominant = next.symbol === 'N'
+      && previousChord
+      && currentChord.quality === 'major'
+      && previousChord.quality === 'minor'
+      && current.confidence >= 0.3
+      && ((currentChord.rootIndex - previousChord.rootIndex + 12) % 12) === 2;
+
+    if (resolvesToMinorTonic || endsAfterMinorPredominant) {
+      current.symbol = `${ROOT_NAMES[currentChord.rootIndex]}7`;
+    }
+  }
+
+  return promoted;
+}
+
 export function detectChordsFromAudio(
   request: AudioChordDetectionRequest,
   onProgress?: (progress: AudioChordDetectionProgress) => void,
@@ -212,6 +363,10 @@ export function detectChordsFromAudio(
   if (windows.length === 0) {
     return [];
   }
+  const options: AudioChordDetectionOptions = {
+    ...DEFAULT_AUDIO_CHORD_DETECTION_OPTIONS,
+    ...request.options,
+  };
 
   onProgress?.({
     completedWindows: 0,
@@ -226,6 +381,7 @@ export function detectChordsFromAudio(
       request.sampleRate,
       request.clipStartOffsetSeconds + (window.startSeconds - request.clipStartOffsetSeconds),
       request.clipStartOffsetSeconds + (window.endSeconds - request.clipStartOffsetSeconds),
+      options,
     );
 
     rawResults.push({
@@ -245,12 +401,18 @@ export function detectChordsFromAudio(
   });
 
   const maxRms = rawResults.reduce((max, result) => Math.max(max, result.rms), 0);
-  const silenceThreshold = Math.max(ABSOLUTE_SILENCE_RMS, maxRms * RELATIVE_SILENCE_RATIO);
+  const sensitivityRatio = clamp((options.sensitivity - 50) / 50, -1, 1);
+  const sensitivityFactor = Math.pow(2, -sensitivityRatio);
+  const silenceThreshold = Math.max(
+    ABSOLUTE_SILENCE_RMS * sensitivityFactor,
+    maxRms * RELATIVE_SILENCE_RATIO * sensitivityFactor,
+  );
+  const noChordThreshold = clamp(options.noChordThreshold, 0, 100) / 100;
   const filtered = rawResults.map(result => (
-    result.rms < silenceThreshold
+    result.rms < silenceThreshold || result.confidence < noChordThreshold
       ? { ...result, symbol: 'N', confidence: 0 }
       : result
   ));
 
-  return smoothDetectedChords(filtered);
+  return applySeventhContextPromotion(smoothDetectedChords(filtered, options), options);
 }

src/util/dialogUtil.ts

@@ -14,6 +14,13 @@ export interface TimeSigResult {
   denominator: number;
 }
 
+export interface ChordDetectionOptionsResult {
+  sensitivity: number;
+  stability: number;
+  noChordThreshold: number;
+  enableSevenths: boolean;
+}
+
 export interface ChoiceOption {
   label: string;
   value: string;
@@ -24,6 +31,7 @@ let _showConfirmFn: ((message: string, options?: ConfirmOptions) => Promise<bool
 let _showPromptFn: ((message: string, defaultValue?: string, options?: PromptOptions) => Promise<string | null>) | null = null;
 let _showTimeSigFn: ((message: string, defaultValue?: TimeSigResult) => Promise<TimeSigResult | null>) | null = null;
 let _showChoiceFn: ((message: string, choices: ChoiceOption[]) => Promise<string | null>) | null = null;
+let _showChordDetectionOptionsFn: ((message: string, defaultValue?: ChordDetectionOptionsResult) => Promise<ChordDetectionOptionsResult | null>) | null = null;
 
 export function registerDialogFns(
   alertFn: (message: string) => Promise<void>,
@@ -31,12 +39,14 @@ export function registerDialogFns(
   promptFn: (message: string, defaultValue?: string, options?: PromptOptions) => Promise<string | null>,
   timeSigFn: (message: string, defaultValue?: TimeSigResult) => Promise<TimeSigResult | null>,
   choiceFn?: (message: string, choices: ChoiceOption[]) => Promise<string | null>,
+  chordDetectionOptionsFn?: (message: string, defaultValue?: ChordDetectionOptionsResult) => Promise<ChordDetectionOptionsResult | null>,
 ) {
   _showAlertFn = alertFn;
   _showConfirmFn = confirmFn;
   _showPromptFn = promptFn;
   _showTimeSigFn = timeSigFn;
   if (choiceFn) _showChoiceFn = choiceFn;
+  if (chordDetectionOptionsFn) _showChordDetectionOptionsFn = chordDetectionOptionsFn;
 }
 
 export function showAlert(message: string): Promise<void> {
@@ -78,3 +88,18 @@ export function showTimeSigPrompt(message: string, defaultValue?: TimeSigResult)
   }
   return _showTimeSigFn(message, defaultValue);
 }
+
+export function showChordDetectionOptions(
+  message: string,
+  defaultValue?: ChordDetectionOptionsResult,
+): Promise<ChordDetectionOptionsResult | null> {
+  if (!_showChordDetectionOptionsFn) {
+    return Promise.resolve(defaultValue ?? {
+      sensitivity: 50,
+      stability: 50,
+      noChordThreshold: 0,
+      enableSevenths: false,
+    });
+  }
+  return _showChordDetectionOptionsFn(message, defaultValue);
+}