change spectrum db to dbFS

src/plugin-ui/BridgeSpectrumAnalyzer.ts

@@ -20,15 +20,17 @@ export class BridgeSpectrumAnalyzer implements SpectrumNativeAnalyzer {
   private sampleRate = 48000
   private magnitudes: Float32Array
   private sideMagnitudes: Float32Array
+  private channelMaxMagnitudes: Float32Array
 
   constructor(fftSize = 2048) {
     this.fftSize = fftSize
     this.magnitudes = new Float32Array(fftSize / 2).fill(FFT_SILENCE_DB)
     this.sideMagnitudes = new Float32Array(fftSize / 2).fill(FFT_SILENCE_DB)
+    this.channelMaxMagnitudes = new Float32Array(fftSize / 2).fill(FFT_SILENCE_DB)
   }
 
   /** Called by the bridge whenever the host emits a new frame. */
-  setMagnitudes(magnitudes: Float32Array, side?: Float32Array): void {
+  setMagnitudes(magnitudes: Float32Array, side?: Float32Array, channelMax?: Float32Array): void {
     if (magnitudes.length !== this.magnitudes.length) {
       this.magnitudes = new Float32Array(magnitudes.length)
     }
@@ -40,6 +42,12 @@ export class BridgeSpectrumAnalyzer implements SpectrumNativeAnalyzer {
       }
       this.sideMagnitudes.set(side)
     }
+
+    const resolvedChannelMax = channelMax && channelMax.length > 0 ? channelMax : magnitudes
+    if (resolvedChannelMax.length !== this.channelMaxMagnitudes.length) {
+      this.channelMaxMagnitudes = new Float32Array(resolvedChannelMax.length)
+    }
+    this.channelMaxMagnitudes.set(resolvedChannelMax)
   }
 
   isAvailable(): boolean {
@@ -51,6 +59,7 @@ export class BridgeSpectrumAnalyzer implements SpectrumNativeAnalyzer {
       this.fftSize = size
       this.magnitudes = new Float32Array(size / 2).fill(FFT_SILENCE_DB)
       this.sideMagnitudes = new Float32Array(size / 2).fill(FFT_SILENCE_DB)
+      this.channelMaxMagnitudes = new Float32Array(size / 2).fill(FFT_SILENCE_DB)
     }
   }
 
@@ -91,6 +100,14 @@ export class BridgeSpectrumAnalyzer implements SpectrumNativeAnalyzer {
     return count
   }
 
+  fillChannelMaxMagnitudes(output: Float32Array): number {
+    const count = Math.min(output.length, this.channelMaxMagnitudes.length)
+    if (count > 0) {
+      output.set(this.channelMaxMagnitudes.subarray(0, count), 0)
+    }
+    return count
+  }
+
   getMagnitudes(): Float32Array {
     return this.magnitudes
   }
@@ -103,6 +120,10 @@ export class BridgeSpectrumAnalyzer implements SpectrumNativeAnalyzer {
     return this.sideMagnitudes
   }
 
+  getChannelMaxMagnitudes(): Float32Array {
+    return this.channelMaxMagnitudes
+  }
+
   process(_audioData: Float32Array): Float32Array {
     return this.magnitudes
   }
@@ -114,5 +135,6 @@ export class BridgeSpectrumAnalyzer implements SpectrumNativeAnalyzer {
   reset(): void {
     this.magnitudes.fill(FFT_SILENCE_DB)
     this.sideMagnitudes.fill(FFT_SILENCE_DB)
+    this.channelMaxMagnitudes.fill(FFT_SILENCE_DB)
   }
 }

src/plugin-ui/SpectrumScope.tsx

@@ -9,7 +9,7 @@ import { spectrumSettingsToOptions } from './spectrumOptions'
 import { getScopeCanvasTransformStyle } from '../renderer/scopeCanvasTransform'
 import { applyPluginScopeCanvasLayout } from './scopeCanvasLayout'
 import {
-  formatSpectrumPeakDb,
+  formatSpectrumPeakDbfs,
   formatSpectrumPeakFrequency,
   resolveFollowingPeakOverlayStyle,
   type CanvasResizeState,
@@ -137,7 +137,7 @@ export default function SpectrumScope({
           className={['scope-module__peak-info', peakMode === 'following' ? 'is-following' : 'is-corner'].join(' ')}
           style={overlayStyle}
         >
-          <span className="scope-module__peak-info-value">{formatSpectrumPeakDb(peak.db)}</span>
+          <span className="scope-module__peak-info-value">{formatSpectrumPeakDbfs(peak.dbfs)}</span>
           <span className="scope-module__peak-info-separator">/</span>
           <span className="scope-module__peak-info-value">{formatSpectrumPeakFrequency(peak.frequencyHz)}</span>
           <span className="scope-module__peak-info-separator">/</span>

src/plugin-ui/juceBridge.ts

@@ -16,12 +16,15 @@ export interface SpectrumFrame {
   magnitudes: Float32Array
   /** Side magnitudes in dB (same length); empty if unavailable. */
   side: Float32Array
+  /** Smoothed max(L, R) magnitudes in dBFS (same length). */
+  channelMax: Float32Array
 }
 
 interface SpectrumFramePayload {
   sampleRate?: number
   magnitudes?: string
   side?: string
+  channelMax?: string
 }
 
 type JuceBackend = {
@@ -100,14 +103,19 @@ export function base64ToFloat32Array(b64: string): Float32Array {
   return new Float32Array(bytes.buffer, 0, byteLength >> 2)
 }
 
-function decodeFrame(payload: unknown): SpectrumFrame | null {
+export function decodeSpectrumFrame(payload: unknown): SpectrumFrame | null {
   if (typeof payload !== 'object' || payload === null) return null
-  const { sampleRate, magnitudes, side } = payload as SpectrumFramePayload
+  const { sampleRate, magnitudes, side, channelMax } = payload as SpectrumFramePayload
   if (typeof magnitudes !== 'string' || magnitudes.length === 0) return null
+  const decodedMagnitudes = base64ToFloat32Array(magnitudes)
+  const decodedChannelMax = typeof channelMax === 'string'
+    ? base64ToFloat32Array(channelMax)
+    : new Float32Array(0)
   return {
     sampleRate: typeof sampleRate === 'number' && sampleRate > 0 ? sampleRate : 48000,
-    magnitudes: base64ToFloat32Array(magnitudes),
+    magnitudes: decodedMagnitudes,
     side: typeof side === 'string' ? base64ToFloat32Array(side) : new Float32Array(0),
+    channelMax: decodedChannelMax.length > 0 ? decodedChannelMax : decodedMagnitudes,
   }
 }
 
@@ -128,6 +136,7 @@ export function connectSpectrumBridge(handlers: SpectrumBridgeHandlers): () => v
     const sampleRate = 48000
     const mid = new Float32Array(binCount)
     const side = new Float32Array(binCount).fill(-100)
+    const channelMax = new Float32Array(binCount)
     let phase = 0
     const tick = (): void => {
       if (disposed) return
@@ -138,8 +147,9 @@ export function connectSpectrumBridge(handlers: SpectrumBridgeHandlers): () => v
         const peak2 = Math.exp(-Math.pow((t - 0.5) * 18, 2)) * 50
         mid[i] = -100 + peak1 + peak2 + Math.random() * 6
         side[i] = -100 + peak2 * 0.4 + Math.random() * 4
+        channelMax[i] = mid[i]
       }
-      handlers.onFrame({ sampleRate, magnitudes: mid, side })
+      handlers.onFrame({ sampleRate, magnitudes: mid, side, channelMax })
       mockRaf = requestAnimationFrame(tick)
     }
     mockRaf = requestAnimationFrame(tick)
@@ -149,7 +159,7 @@ export function connectSpectrumBridge(handlers: SpectrumBridgeHandlers): () => v
     if (disposed) return
     if (backend) {
       listenerId = backend.addEventListener('spectrumFrame', (payload) => {
-        const frame = decodeFrame(payload)
+        const frame = decodeSpectrumFrame(payload)
         if (frame) handlers.onFrame(frame)
       })
       handlers.onConnected?.(false)

src/plugin-ui/main.tsx

@@ -185,7 +185,7 @@ function buildApp(): JSX.Element {
   const analyzer = new BridgeSpectrumAnalyzer(2048)
   connectSpectrumBridge({
     onFrame: (frame) => {
-      analyzer.setMagnitudes(frame.magnitudes, frame.side)
+      analyzer.setMagnitudes(frame.magnitudes, frame.side, frame.channelMax)
       dataSource.setSampleRate(frame.sampleRate)
       dataSource.setPlaying(true)
     },

src/plugin-ui/peakOverlay.ts

@@ -28,11 +28,11 @@ function clampNumber(value: number, min: number, max: number): number {
   return Math.min(max, Math.max(min, value))
 }
 
-export function formatSpectrumPeakDb(value: number): string {
+export function formatSpectrumPeakDbfs(value: number): string {
   if (!Number.isFinite(value)) {
     return '--'
   }
-  return `${value >= 0 ? '+' : ''}${value.toFixed(2)}dB`
+  return `${value >= 0 ? '+' : ''}${value.toFixed(2)}dBFS`
 }
 
 export function formatSpectrumPeakFrequency(value: number): string {