add manual microphone gain and signal meter

public/app.js

@@ -1,5 +1,6 @@
 import * as matrixcs from 'matrix-js-sdk';
 import cytoscape from 'cytoscape';
+import { AudioManager } from './audio-manager.js';
 
 function captureRumIssue(message, severity = 'ERROR', extra = {}) {
   const rum = globalThis.OtelRUM?.last;
@@ -47,6 +48,8 @@ const S = {
   screenStreams: new Map(), // streamId -> local MediaStream
   screenSenders: new Map(), // peerId -> Map(streamId -> RTCRtpSender[])
   audioCtx: null,
+  audioManager: new AudioManager(),
+  rawMicStream: null,
   me: { x: 50, y: 50 },
   muted: false,
   deafened: false,
@@ -331,15 +334,16 @@ async function switchAudioInput(deviceId) {
     return;
   }
 
-  const nextTrack = nextStream.getAudioTracks()[0];
+  const nextOutput = await S.audioManager.attachInput(nextStream);
+  const nextTrack = nextOutput.getAudioTracks()[0];
   nextTrack.enabled = !S.muted;
   await Promise.all([...S.peers.values()].map(async (peer) => {
     if (!peer.pc) return;
     const sender = peer.pc.getSenders().find((item) => item.track && item.track.kind === 'audio');
     if (sender) await sender.replaceTrack(nextTrack);
   }));
-  S.micStream.getTracks().forEach((track) => track.stop());
-  S.micStream = nextStream;
+  S.rawMicStream = nextStream;
+  S.micStream = nextOutput;
   updateMicButton();
   toast('Microphone changed', 'ok');
 }
@@ -355,8 +359,8 @@ async function joinVoice(room) {
 
   // Mic permission & AudioContext: request immediately on the user-click gesture
   // so browsers don't block the microphone permission prompt or audio autoplay policy.
-  if (!S.audioCtx) S.audioCtx = new AudioContext();
-  await S.audioCtx.resume().catch(() => {});
+  await S.audioManager.ensureContext();
+  S.audioCtx = S.audioManager.context;
   orientListener();
 
   // Attach a one-time gesture listener in case browser autoplay policy keeps AudioContext suspended
@@ -369,7 +373,8 @@ async function joinVoice(room) {
   window.addEventListener('keydown', resumeCtx, { passive: true });
 
   try {
-    S.micStream = await navigator.mediaDevices.getUserMedia(microphoneConstraints());
+    S.rawMicStream = await navigator.mediaDevices.getUserMedia(microphoneConstraints());
+    S.micStream = await S.audioManager.attachInput(S.rawMicStream);
     populateAudioInputs();
   } catch {
     S.micStream = null;
@@ -423,7 +428,9 @@ function leaveVoice(reason) {
   S.peers.clear();
   if (S.pingTimer) { clearInterval(S.pingTimer); S.pingTimer = null; }
   if (S.ws) { try { S.ws.close(); } catch {} S.ws = null; }
-  if (S.micStream) { S.micStream.getTracks().forEach((t) => t.stop()); S.micStream = null; }
+  S.audioManager.stop();
+  S.rawMicStream = null;
+  S.micStream = null;
   // Keep share buttons enabled so clicking one prompts the user to join a channel
   updateMicButton();
   document.querySelectorAll('.channel.voice').forEach((c) => c.classList.remove('active'));
@@ -1106,16 +1113,20 @@ function rms(analyser) {
   return Math.sqrt(sum / meterBuf.length);
 }
 
-let localAnalyser = null;
+function updateMicSignal(level = S.audioManager.getLevel()) {
+  const meter = $('#mic-level');
+  const value = $('#mic-level-value');
+  const clipping = $('#mic-clipping');
+  if (meter) meter.value = Math.min(1, level.rms * 3);
+  if (value) value.textContent = level.rms > 0 ? `${Math.round(20 * Math.log10(level.rms))} dB` : '-∞ dB';
+  if (clipping) clipping.classList.toggle('hidden', !level.clipping);
+}
+
 setInterval(() => {
   if (!S.audioCtx) return;
-  if (S.micStream && !localAnalyser) {
-    const src = S.audioCtx.createMediaStreamSource(S.micStream);
-    localAnalyser = S.audioCtx.createAnalyser();
-    localAnalyser.fftSize = 256;
-    src.connect(localAnalyser); // tap only — not connected to destination (no echo)
-  }
-  const meSpeaking = localAnalyser && !S.muted && rms(localAnalyser) > 0.04;
+  const localLevel = S.audioManager.getLevel();
+  updateMicSignal(localLevel);
+  const meSpeaking = S.micStream && !S.muted && localLevel.rms > 0.04;
   els.meAvatar.classList.toggle('speaking', !!meSpeaking);
   let changed = false;
   for (const peer of S.peers.values()) {
@@ -2192,6 +2203,9 @@ navigator.mediaDevices?.addEventListener('devicechange', populateAudioInputs);
 // ---------------------------------------------------------------------------
 function openSettings() {
   populateAudioInputs();
+  const gain = $('#mic-gain');
+  if (gain) gain.value = S.audioManager.gain;
+  updateMicGainUi();
   const override = localStorage.getItem(LS_ICE);
   $('#override-enabled').checked = !!override;
   const current = override ? JSON.parse(override) : effectiveIce();
@@ -2202,6 +2216,17 @@ function openSettings() {
   );
   $('#modal-backdrop').classList.remove('hidden');
 }
+function updateMicGainUi() {
+  const gain = S.audioManager.gain;
+  const input = $('#mic-gain');
+  const value = $('#mic-gain-value');
+  if (input) input.value = gain;
+  if (value) value.textContent = `${Math.round(gain * 100)}%`;
+}
+$('#mic-gain').oninput = (ev) => {
+  S.audioManager.setGain(ev.target.value);
+  updateMicGainUi();
+};
 $('#audio-input').onchange = (ev) => switchAudioInput(ev.target.value);
 $('#ice-cancel').onclick = () => $('#modal-backdrop').classList.add('hidden');
 $('#modal-backdrop').onclick = (ev) => {