From 22ab89994bce7ce21e504ec42a4397f16d1f1b55 Mon Sep 17 00:00:00 2001
From: lebaudantoine <lebaud.antoine131@gmail.com>
Date: Tue, 11 Aug 2026 18:39:50 +0200
Subject: [PATCH] =?UTF-8?q?=E2=9C=A8(frontend)=20add=20a=20silent-micropho?=
 =?UTF-8?q?ne=20watcher=20on=20join=20and=20room=20screens?=
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Introduce a watcher that listens to the microphone stream and detects
when it stays silent, which is often a sign of an underlying issue:
missing OS permissions, a faulty device, or a hardware lock (e.g. a
physical mute switch).

Wire the watcher on both the join and room screens, so users get a
signal that something is off before it turns into an actual meeting
problem.
---
 CHANGELOG.md                                  |   1 +
 .../src/features/analytics/telemetry.ts       |   3 +
 .../src/features/rooms/components/Join.tsx    |   2 +
 .../rooms/components/SilentMicDetector.tsx    | 123 ++++++++++++++++++
 .../rooms/components/SilentMicDialog.tsx      |  64 +++++++++
 .../controls/Device/AudioLevelGauge.tsx       |  26 +---
 .../controls/Device/ToggleDevice.tsx          |  14 ++
 .../rooms/livekit/hooks/useIsTrackMuted.ts    |  24 ++++
 .../rooms/livekit/prefabs/VideoConference.tsx |   2 +
 .../src/features/rooms/routes/Room.tsx        |   2 +
 src/frontend/src/locales/de/rooms.json        |  15 +++
 src/frontend/src/locales/en/rooms.json        |  15 +++
 src/frontend/src/locales/fr/rooms.json        |  15 +++
 src/frontend/src/locales/nl/rooms.json        |  15 +++
 src/frontend/src/stores/silentMic.ts          |  98 ++++++++++++++
 15 files changed, 395 insertions(+), 24 deletions(-)
 create mode 100644 src/frontend/src/features/rooms/components/SilentMicDetector.tsx
 create mode 100644 src/frontend/src/features/rooms/components/SilentMicDialog.tsx
 create mode 100644 src/frontend/src/features/rooms/livekit/hooks/useIsTrackMuted.ts
 create mode 100644 src/frontend/src/stores/silentMic.ts

diff --git a/CHANGELOG.md b/CHANGELOG.md
index ce6bd595..02839772 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -17,6 +17,7 @@ and this project adheres to
 - ⚗️(frontend) capture console.error in PostHog
 - 📈(frontend) snapshot media devices on the happy path
 - 🚸(frontend) guide users when the OS blocks browser media access
+- ✨(frontend) add a silent-microphone watcher on join and room screens
 
 ### Changed
 
diff --git a/src/frontend/src/features/analytics/telemetry.ts b/src/frontend/src/features/analytics/telemetry.ts
index 20b0dc69..5181b8ab 100644
--- a/src/frontend/src/features/analytics/telemetry.ts
+++ b/src/frontend/src/features/analytics/telemetry.ts
@@ -136,6 +136,9 @@ export const captureMediaEvent = async (
     | 'media-device-success'
     | 'device-not-found'
     | 'permissions-denied'
+    | 'silent-mic-detected'
+    | 'silent-mic-analyser-unavailable'
+    | 'silent-mic-recovered'
     | 'visit-room'
     | 'connection-event',
   props: Record<string, unknown>
diff --git a/src/frontend/src/features/rooms/components/Join.tsx b/src/frontend/src/features/rooms/components/Join.tsx
index 75d03942..1c943367 100644
--- a/src/frontend/src/features/rooms/components/Join.tsx
+++ b/src/frontend/src/features/rooms/components/Join.tsx
@@ -30,6 +30,7 @@ import {
 import { useCannotUseDevice } from '../livekit/hooks/useCannotUseDevice'
 import { useDeviceMissing } from '../livekit/hooks/useDeviceMissing'
 import { useJoinTracks } from '../livekit/hooks/useJoinTracks'
+import { SilentMicDetector } from './SilentMicDetector'
 
 const styles = {
   page: css({
@@ -460,6 +461,7 @@ export const Join = ({
 
   return (
     <Screen footer={false}>
+      <SilentMicDetector track={audioTrack} context="join" />
       <div className={styles.page}>
         <div className={styles.previewColumn}>
           <div className={styles.previewStack}>
diff --git a/src/frontend/src/features/rooms/components/SilentMicDetector.tsx b/src/frontend/src/features/rooms/components/SilentMicDetector.tsx
new file mode 100644
index 00000000..19023d15
--- /dev/null
+++ b/src/frontend/src/features/rooms/components/SilentMicDetector.tsx
@@ -0,0 +1,123 @@
+import { useEffect, useRef } from 'react'
+import { useSnapshot } from 'valtio'
+import { createAudioAnalyser, LocalAudioTrack } from 'livekit-client'
+import { useLocalParticipant } from '@livekit/components-react'
+import { reportMicSample, silentMicStore } from '@/stores/silentMic'
+import { captureMediaEvent } from '@/features/analytics/telemetry'
+import { useIsTrackMuted } from '../livekit/hooks/useIsTrackMuted'
+
+// A live microphone always has a noise floor; only a signal pinned to
+// zero counts as silent (no audio data flowing at all).
+const SILENT_VOLUME_EPSILON = 0.0001
+const TICK_MS = 1_000
+
+type SilentMicContext = 'join' | 'room'
+
+const ActiveDetector = ({
+  track,
+  context,
+}: {
+  track: LocalAudioTrack
+  context: SilentMicContext
+}) => {
+  const isMuted = useIsTrackMuted(track)
+
+  // The interval reads through refs so state updates never re-arm the
+  // timer or the analyser.
+  const mutedRef = useRef(isMuted)
+  mutedRef.current = isMuted
+  const contextRef = useRef(context)
+  contextRef.current = context
+
+  useEffect(() => {
+    let audioAnalyser: ReturnType<typeof createAudioAnalyser>
+    try {
+      audioAnalyser = createAudioAnalyser(track, {
+        fftSize: 256,
+        smoothingTimeConstant: 0.7,
+      })
+    } catch {
+      void captureMediaEvent('silent-mic-analyser-unavailable', {
+        context: contextRef.current,
+      })
+      return
+    }
+    const { analyser, calculateVolume, cleanup } = audioAnalyser
+
+    const tick = () => {
+      // Zero volume is only evidence of silence when audio data is
+      // actually flowing. Skip the sample when:
+      //  - the mic is intentionally muted;
+      //  - the tab is backgrounded (suspended AudioContext reads as zero);
+      //  - the AudioContext is not running yet — Chrome keeps it
+      //    'suspended' until a user gesture on pages loaded without
+      //    activation, and a suspended analyser reports zeros for a
+      //    perfectly healthy microphone.
+      if (
+        mutedRef.current ||
+        document.visibilityState !== 'visible' ||
+        analyser.context.state !== 'running'
+      ) {
+        return
+      }
+      const result = reportMicSample({
+        trackId: track.mediaStreamTrack?.id,
+        silent: calculateVolume() <= SILENT_VOLUME_EPSILON,
+        deltaMs: TICK_MS,
+      })
+      if (result === 'silent-detected') {
+        void captureMediaEvent('silent-mic-detected', {
+          context: contextRef.current,
+          media_stream_track_muted: track.mediaStreamTrack?.muted ?? null,
+        })
+      } else if (result === 'recovered') {
+        void captureMediaEvent('silent-mic-recovered', {
+          context: contextRef.current,
+        })
+      }
+    }
+
+    const interval = window.setInterval(tick, TICK_MS)
+    return () => {
+      window.clearInterval(interval)
+      void cleanup()
+    }
+  }, [track])
+
+  return null
+}
+
+/**
+ * One-shot silent-mic check (see stores/silentMic.ts). Renders nothing;
+ * mounts the volume watcher only while the check is still undecided so
+ * the analyser goes away as soon as the outcome is known.
+ */
+export const SilentMicDetector = ({
+  track,
+  context,
+}: {
+  track?: LocalAudioTrack
+  context: SilentMicContext
+}) => {
+  const { status } = useSnapshot(silentMicStore)
+  if ((status !== 'watching' && status !== 'silent') || !track) {
+    return null
+  }
+  return (
+    <ActiveDetector
+      key={track.mediaStreamTrack?.id}
+      track={track}
+      context={context}
+    />
+  )
+}
+
+/** Room-side variant: watches the published local microphone track. */
+export const RoomSilentMicDetector = () => {
+  const { microphoneTrack } = useLocalParticipant()
+  const track =
+    microphoneTrack?.track instanceof LocalAudioTrack
+      ? microphoneTrack.track
+      : undefined
+  return <SilentMicDetector track={track} context="room" />
+}
diff --git a/src/frontend/src/features/rooms/components/SilentMicDialog.tsx b/src/frontend/src/features/rooms/components/SilentMicDialog.tsx
new file mode 100644
index 00000000..90b185e9
--- /dev/null
+++ b/src/frontend/src/features/rooms/components/SilentMicDialog.tsx
@@ -0,0 +1,64 @@
+import { useTranslation } from 'react-i18next'
+import { useSnapshot } from 'valtio'
+import { css } from '@/styled-system/css'
+import { Button, Dialog, H, P } from '@/primitives'
+import {
+  closeSilentMicDialog,
+  discardSilentMicDetection,
+  silentMicStore,
+} from '@/stores/silentMic'
+
+/**
+ * Opened from the "!" badge on the microphone toggle when the silent-mic
+ * check tripped (see stores/silentMic.ts). Explains the likely causes
+ * and lets the user opt out of the detection for good.
+ */
+export const SilentMicDialog = () => {
+  const { t } = useTranslation('rooms', { keyPrefix: 'silentMic.dialog' })
+  const { isDialogOpen } = useSnapshot(silentMicStore)
+
+  return (
+    <Dialog
+      isOpen={isDialogOpen}
+      role="dialog"
+      type="flex"
+      title=""
+      aria-label={t('title')}
+      onClose={closeSilentMicDialog}
+    >
+      <div
+        className={css({
+          maxWidth: '500px',
+        })}
+      >
+        <H lvl={1}>{t('title')}</H>
+        <P>{t('intro')}</P>
+        <ul className={css({ listStyle: 'disc', paddingLeft: '24px' })}>
+          <li>{t('causes.system')}</li>
+          <li>{t('causes.hardware')}</li>
+          <li>{t('causes.wrongDevice')}</li>
+        </ul>
+        <P>{t('hint')}</P>
+        <div
+          className={css({
+            marginTop: '1.5rem',
+            display: 'flex',
+            gap: '1rem',
+            flexWrap: 'wrap',
+          })}
+        >
+          <Button variant="primary" size="sm" onPress={closeSilentMicDialog}>
+            {t('close')}
+          </Button>
+          <Button
+            variant="tertiary"
+            size="sm"
+            onPress={discardSilentMicDetection}
+          >
+            {t('discard')}
+          </Button>
+        </div>
+      </div>
+    </Dialog>
+  )
+}
diff --git a/src/frontend/src/features/rooms/livekit/components/controls/Device/AudioLevelGauge.tsx b/src/frontend/src/features/rooms/livekit/components/controls/Device/AudioLevelGauge.tsx
index b3da87a7..76efd208 100644
--- a/src/frontend/src/features/rooms/livekit/components/controls/Device/AudioLevelGauge.tsx
+++ b/src/frontend/src/features/rooms/livekit/components/controls/Device/AudioLevelGauge.tsx
@@ -1,10 +1,10 @@
-import { useEffect, useState } from 'react'
-import { LocalAudioTrack, TrackEvent } from 'livekit-client'
+import { LocalAudioTrack } from 'livekit-client'
 import { useTrackVolume } from '@livekit/components-react'
 import { useTranslation } from 'react-i18next'
 import { RiMicLine, RiMicOffLine } from '@remixicon/react'
 import { styled } from '@/styled-system/jsx'
 import { Text } from '@/primitives'
+import { useIsTrackMuted } from '../../../hooks/useIsTrackMuted'
 
 const StyledContainer = styled('div', {
   base: {
@@ -77,28 +77,6 @@ type AudioLevelGaugeProps = {
   variant?: Theme
 }
 
-const useIsTrackMuted = (track?: LocalAudioTrack) => {
-  const [isMuted, setIsMuted] = useState(() => track?.isMuted ?? true)
-
-  useEffect(() => {
-    if (!track) {
-      setIsMuted(true)
-      return
-    }
-    setIsMuted(track.isMuted)
-    const onMuted = () => setIsMuted(true)
-    const onUnmuted = () => setIsMuted(false)
-    track.on(TrackEvent.Muted, onMuted)
-    track.on(TrackEvent.Unmuted, onUnmuted)
-    return () => {
-      track.off(TrackEvent.Muted, onMuted)
-      track.off(TrackEvent.Unmuted, onUnmuted)
-    }
-  }, [track])
-
-  return isMuted
-}
-
 const LevelBar = ({
   track,
   theme,
diff --git a/src/frontend/src/features/rooms/livekit/components/controls/Device/ToggleDevice.tsx b/src/frontend/src/features/rooms/livekit/components/controls/Device/ToggleDevice.tsx
index 5a57ab82..69aed962 100644
--- a/src/frontend/src/features/rooms/livekit/components/controls/Device/ToggleDevice.tsx
+++ b/src/frontend/src/features/rooms/livekit/components/controls/Device/ToggleDevice.tsx
@@ -17,6 +17,8 @@ import { MediaDeviceErrorAlert } from '@/features/rooms/components/MediaDeviceEr
 import type { ButtonRecipeProps } from '@/primitives/buttonRecipe'
 import type { ToggleButtonProps } from '@/primitives/ToggleButton'
 import { openPermissionsDialog } from '@/stores/permissions'
+import { openSilentMicDialog, silentMicStore } from '@/stores/silentMic'
+import { useSnapshot } from 'valtio'
 import { useCannotUseDevice } from '../../../hooks/useCannotUseDevice'
 import { useDeviceMissing } from '../../../hooks/useDeviceMissing'
 import { requestDevicePermission } from '../../../hooks/useJoinTracks'
@@ -95,6 +97,12 @@ export const ToggleDevice = <T extends ToggleSource>({
   const deviceIcons = useDeviceIcons(kind)
   const cannotUseDevice = useCannotUseDevice(kind)
   const deviceMissing = useDeviceMissing(kind)
+  const { status: silentMicStatus } = useSnapshot(silentMicStore)
+  const silentMicWarning =
+    kind === 'audioinput' &&
+    silentMicStatus === 'silent' &&
+    !cannotUseDevice &&
+    !deviceMissing
   const deviceShortcut = useDeviceShortcut(kind)
   const announce = useScreenReaderAnnounce()
 
@@ -178,6 +186,12 @@ export const ToggleDevice = <T extends ToggleSource>({
           }
         />
       )}
+      {silentMicWarning && (
+        <PermissionNeededButton
+          tooltip={t('tooltip', { keyPrefix: 'silentMic' })}
+          onPress={openSilentMicDialog}
+        />
+      )}
       <ToggleButton
         isSelected={!enabled}
         isDisabled={isDisabled}
diff --git a/src/frontend/src/features/rooms/livekit/hooks/useIsTrackMuted.ts b/src/frontend/src/features/rooms/livekit/hooks/useIsTrackMuted.ts
new file mode 100644
index 00000000..f5fa8b60
--- /dev/null
+++ b/src/frontend/src/features/rooms/livekit/hooks/useIsTrackMuted.ts
@@ -0,0 +1,24 @@
+import { type LocalAudioTrack, TrackEvent } from 'livekit-client'
+import { useEffect, useState } from 'react'
+
+export const useIsTrackMuted = (track?: LocalAudioTrack) => {
+  const [isMuted, setIsMuted] = useState(() => track?.isMuted ?? true)
+
+  useEffect(() => {
+    if (!track) {
+      setIsMuted(true)
+      return
+    }
+    setIsMuted(track.isMuted)
+    const onMuted = () => setIsMuted(true)
+    const onUnmuted = () => setIsMuted(false)
+    track.on(TrackEvent.Muted, onMuted)
+    track.on(TrackEvent.Unmuted, onUnmuted)
+    return () => {
+      track.off(TrackEvent.Muted, onMuted)
+      track.off(TrackEvent.Unmuted, onUnmuted)
+    }
+  }, [track])
+
+  return isMuted
+}
diff --git a/src/frontend/src/features/rooms/livekit/prefabs/VideoConference.tsx b/src/frontend/src/features/rooms/livekit/prefabs/VideoConference.tsx
index 55b145ce..53f42f67 100644
--- a/src/frontend/src/features/rooms/livekit/prefabs/VideoConference.tsx
+++ b/src/frontend/src/features/rooms/livekit/prefabs/VideoConference.tsx
@@ -26,6 +26,7 @@ import { StageLayout } from '@/features/layout/components/StageLayout'
 import { PinAnnouncer } from '@/features/layout/components/PinAnnouncer'
 import { ChatProvider } from '@/features/chat/components/ChatProvider'
 import { SyncDevicePreferences } from '@/features/rooms/livekit/components/SyncDevicePreferences'
+import { RoomSilentMicDetector } from '@/features/rooms/components/SilentMicDetector'
 
 /**
  * @public
@@ -65,6 +66,7 @@ export function VideoConference({ ...props }: VideoConferenceProps) {
       <RoomMetadataSynchronizer />
       <ConnectionObserver />
       <SyncDevicePreferences />
+      <RoomSilentMicDetector />
       <MediaStateObserver />
       <ChatProvider />
       <VideoResolutionSubscription />
diff --git a/src/frontend/src/features/rooms/routes/Room.tsx b/src/frontend/src/features/rooms/routes/Room.tsx
index 2b398a68..8dad5b58 100644
--- a/src/frontend/src/features/rooms/routes/Room.tsx
+++ b/src/frontend/src/features/rooms/routes/Room.tsx
@@ -7,6 +7,7 @@ import { useUser } from '@/features/auth/api/useUser'
 import { Conference } from '../components/Conference'
 import { Join } from '../components/Join'
 import { Permissions } from '../components/Permissions'
+import { SilentMicDialog } from '../components/SilentMicDialog'
 import { useKeyboardShortcuts } from '@/features/shortcuts/useKeyboardShortcuts'
 import {
   isRoomValid,
@@ -21,6 +22,7 @@ const BaseRoom = ({ children }: { children: ReactNode }) => {
   return (
     <UserAware>
       <Permissions />
+      <SilentMicDialog />
       {children}
     </UserAware>
   )
diff --git a/src/frontend/src/locales/de/rooms.json b/src/frontend/src/locales/de/rooms.json
index 0e908f6a..25380d2c 100644
--- a/src/frontend/src/locales/de/rooms.json
+++ b/src/frontend/src/locales/de/rooms.json
@@ -186,6 +186,21 @@
     },
     "openSettings": "Systemeinstellungen öffnen"
   },
+  "silentMic": {
+    "tooltip": "Ihr Mikrofon ist aktiviert, aber es wird kein Ton erkannt. Klicken Sie für weitere Informationen.",
+    "dialog": {
+      "title": "Kein Ton erkannt",
+      "intro": "Ihr Mikrofon ist aktiviert, aber seit einiger Zeit wird kein Ton erkannt. Überprüfen Sie Folgendes:",
+      "causes": {
+        "system": "Der Zugriff auf das Mikrofon wird möglicherweise durch die Datenschutzeinstellungen Ihres Systems blockiert.",
+        "hardware": "Möglicherweise ist ein Stummschalter aktiviert oder das Mikrofon ist nicht angeschlossen oder defekt.",
+        "wrongDevice": "Möglicherweise ist das falsche Mikrofon ausgewählt. Wählen Sie im Mikrofonmenü ein anderes aus."
+      },
+      "hint": "Sprechen Sie erneut, nachdem Sie diese Punkte überprüft haben. Die Warnung verschwindet, sobald ein Ton erkannt wird.",
+      "close": "Verstanden",
+      "discard": "Erkennung eines stummen Mikrofons deaktivieren"
+    }
+  },
   "permissionsButton": {
     "tooltip": "Mehr Infos",
     "ariaLabel": "Problem mit Berechtigungen. Mehr Infos anzeigen"
diff --git a/src/frontend/src/locales/en/rooms.json b/src/frontend/src/locales/en/rooms.json
index 0d8fb4d0..34e4758b 100644
--- a/src/frontend/src/locales/en/rooms.json
+++ b/src/frontend/src/locales/en/rooms.json
@@ -186,6 +186,21 @@
     },
     "openSettings": "Open system settings"
   },
+  "silentMic": {
+    "tooltip": "Your microphone is on, but no sound is being detected. Click to learn more.",
+    "dialog": {
+      "title": "No sound detected",
+      "intro": "Your microphone is on, but we haven't detected any sound for a while. Check the following:",
+      "causes": {
+        "system": "Your system's privacy settings may be blocking microphone access.",
+        "hardware": "A mute switch may be turned on, or your microphone may be disconnected or faulty.",
+        "wrongDevice": "The wrong microphone may be selected. Try choosing another one from the microphone menu."
+      },
+      "hint": "Speak again after checking these settings. This warning will disappear as soon as sound is detected.",
+      "close": "Got it",
+      "discard": "Turn off silent microphone detection"
+    }
+  },
   "permissionsButton": {
     "tooltip": "More info",
     "ariaLabel": "Permissions issue. Show more info"
diff --git a/src/frontend/src/locales/fr/rooms.json b/src/frontend/src/locales/fr/rooms.json
index ccacbf06..df55f557 100644
--- a/src/frontend/src/locales/fr/rooms.json
+++ b/src/frontend/src/locales/fr/rooms.json
@@ -186,6 +186,21 @@
     },
     "openSettings": "Ouvrir les réglages système"
   },
+  "silentMic": {
+    "tooltip": "Votre micro est activé, mais aucun son n'est détecté. Cliquez pour en savoir plus.",
+    "dialog": {
+      "title": "Aucun son détecté",
+      "intro": "Votre micro est activé, mais aucun son n'est détecté depuis un moment. Vérifiez les points suivants :",
+      "causes": {
+        "system": "L'accès au micro est peut-être bloqué dans les réglages de confidentialité de votre système.",
+        "hardware": "Un bouton ou interrupteur coupe peut-être le micro, ou celui-ci est débranché ou défectueux.",
+        "wrongDevice": "Un autre micro est peut-être sélectionné. Essayez d'en choisir un autre dans le menu du micro."
+      },
+      "hint": "Parlez à nouveau après avoir vérifié ces points. L'avertissement disparaîtra dès qu'un son sera détecté.",
+      "close": "Compris",
+      "discard": "Désactiver cette détection"
+    }
+  },
   "permissionsButton": {
     "tooltip": "Plus d'infos",
     "ariaLabel": "Problème de permissions. Afficher plus d'infos"
diff --git a/src/frontend/src/locales/nl/rooms.json b/src/frontend/src/locales/nl/rooms.json
index 209da973..f28f727f 100644
--- a/src/frontend/src/locales/nl/rooms.json
+++ b/src/frontend/src/locales/nl/rooms.json
@@ -186,6 +186,21 @@
     },
     "openSettings": "Systeeminstellingen openen"
   },
+  "silentMic": {
+    "tooltip": "Je microfoon staat aan, maar er wordt geen geluid gedetecteerd. Klik voor meer informatie.",
+    "dialog": {
+      "title": "Geen geluid gedetecteerd",
+      "intro": "Je microfoon staat aan, maar er is al een tijdje geen geluid gedetecteerd. Controleer het volgende:",
+      "causes": {
+        "system": "De privacyinstellingen van je systeem blokkeren mogelijk de toegang tot je microfoon.",
+        "hardware": "Mogelijk staat er een mute-schakelaar aan, of is je microfoon niet aangesloten of defect.",
+        "wrongDevice": "Mogelijk is de verkeerde microfoon geselecteerd. Kies een andere microfoon in het microfoonmenu."
+      },
+      "hint": "Spreek opnieuw nadat je dit hebt gecontroleerd. De waarschuwing verdwijnt zodra er geluid wordt gedetecteerd.",
+      "close": "Begrepen",
+      "discard": "Detectie van een stille microfoon uitschakelen"
+    }
+  },
   "permissionsButton": {
     "tooltip": "Meer info",
     "ariaLabel": "Probleem met machtigingen. Meer info weergeven"
diff --git a/src/frontend/src/stores/silentMic.ts b/src/frontend/src/stores/silentMic.ts
new file mode 100644
index 00000000..bd98b8b8
--- /dev/null
+++ b/src/frontend/src/stores/silentMic.ts
@@ -0,0 +1,98 @@
+import { proxy } from 'valtio'
+import { captureEvent } from '@/features/analytics/telemetry'
+
+const DISCARD_STORAGE_KEY = 'silent-mic-detection-discarded'
+
+/**
+ * One-shot UX check: a live microphone always produces at least a noise
+ * floor, so a mic that stays pinned to zero for a whole minute is not a
+ * quiet room — it is an OS-level permission block, a hardware mute
+ * switch, or a dead device. The check runs on the join screen and in
+ * the room until it settles:
+ *
+ *   watching → passed     first non-zero sample (check is over, no UI)
+ *   watching → silent     45s of accumulated zero signal (warning badge)
+ *   silent   → passed     sound finally arrives (warning auto-clears)
+ *   any      → discarded  user opts out (persisted on this browser)
+ */
+export type SilentMicStatus = 'watching' | 'silent' | 'passed' | 'discarded'
+
+const isDiscardPersisted = (): boolean => {
+  try {
+    return localStorage.getItem(DISCARD_STORAGE_KEY) === '1'
+  } catch {
+    return false
+  }
+}
+
+export const silentMicStore = proxy({
+  status: (isDiscardPersisted() ? 'discarded' : 'watching') as SilentMicStatus,
+  isDialogOpen: false,
+})
+
+const SILENT_DURATION_MS = 10_000
+
+// Accumulation is module state, not store state: it changes every tick
+// and must survive the join → room transition without re-rendering
+// anything.
+let silentMs = 0
+let watchedTrackId: string | undefined
+
+export type SilentMicSampleResult = 'silent-detected' | 'recovered' | null
+
+/**
+ * Feed one detection sample. Returns the transition it caused, so the
+ * caller can attach telemetry with its own context.
+ */
+export const reportMicSample = ({
+  trackId,
+  silent,
+  deltaMs,
+}: {
+  trackId?: string
+  silent: boolean
+  deltaMs: number
+}): SilentMicSampleResult => {
+  const { status } = silentMicStore
+  if (status === 'discarded' || status === 'passed') return null
+
+  if (trackId !== watchedTrackId) {
+    // New capture (device switch, re-acquire): fresh window.
+    watchedTrackId = trackId
+    silentMs = 0
+  }
+
+  if (!silent) {
+    silentMs = 0
+    silentMicStore.status = 'passed'
+    silentMicStore.isDialogOpen = false
+    return status === 'silent' ? 'recovered' : null
+  }
+
+  if (status !== 'watching') return null
+  silentMs += deltaMs
+  if (silentMs >= SILENT_DURATION_MS) {
+    silentMicStore.status = 'silent'
+    return 'silent-detected'
+  }
+  return null
+}
+
+export const openSilentMicDialog = () => {
+  silentMicStore.isDialogOpen = true
+}
+
+export const closeSilentMicDialog = () => {
+  silentMicStore.isDialogOpen = false
+}
+
+export const discardSilentMicDetection = () => {
+  silentMicStore.status = 'discarded'
+  silentMicStore.isDialogOpen = false
+  try {
+    localStorage.setItem(DISCARD_STORAGE_KEY, '1')
+  } catch {
+    /* private mode: the opt-out just won't persist */
+  }
+  captureEvent('silent-mic-discarded')
+}