fix hifi mode

public/app.js

@@ -33,6 +33,11 @@ window.addEventListener('unhandledrejection', (event) => {
 // ---------------------------------------------------------------------------
 const ROOM_UNITS = 100;          // spatial plane is 0..100 x 0..100
 const SPATIAL_SCALE = 0.12;      // room units -> audio world units
+// Hi-Fi rooms: stereo Opus at 256 kbps with echo cancellation disabled —
+// for music/listening channels where fidelity beats echo-proofing. Marked
+// with a HI-FI badge in the channel list.
+const HIFI_ROOMS = new Set(['code', 'gaming']);
+function roomIsHifi(room = S.room) { return HIFI_ROOMS.has(room); }
 const FALLBACK_ICE = { iceServers: [{ urls: ['stun:turn.k6n.net:3478', 'stun:stun.l.google.com:19302'] }] };
 const LS_NAME = 'voicepoc.nick';
 const LS_ICE = 'voicepoc.iceOverride';
@@ -139,15 +144,39 @@ async function tuneAudioSender(sender) {
   if (!sender?.getParameters || !sender?.setParameters) return;
   const params = sender.getParameters();
   if (!params.encodings?.length) params.encodings = [{}];
-  // 128 kbps keeps Opus in its fullband LD/MD modes with headroom for FEC;
-  // 64 kbps audibly compresses louder/denser speech. DTX stays off so the
-  // channel doesn't pump in and out of low-bitrate comfort noise.
-  params.encodings[0].maxBitrate = 128000;
+  // Hi-Fi rooms get 256 kbps stereo (see HIFI_ROOMS); elsewhere 128 kbps
+  // keeps Opus in its fullband LD/MD modes with headroom for FEC — 64 kbps
+  // audibly compresses louder/denser speech. DTX stays off so the channel
+  // doesn't pump in and out of low-bitrate comfort noise.
+  params.encodings[0].maxBitrate = roomIsHifi() ? 256000 : 128000;
   params.encodings[0].dtx = false;
   params.encodings[0].priority = 'high';
   await sender.setParameters(params);
 }
 
+// Hi-Fi rooms force Opus stereo and lift the in-band bitrate cap. The sender
+// encodings' maxBitrate alone is not enough: Chrome clamps Opus to the SDP's
+// maxaveragebandwidth, and stereo only survives the wire when both sides
+// declare stereo=1 in fmtp. Applied to our local offers AND answers.
+function mungeOpusHifi(sdp) {
+  const pts = [...sdp.matchAll(/a=rtpmap:(\d+) opus\/48000\/2\r?\n/g)].map((m) => m[1]);
+  if (!pts.length) return sdp;
+  const extra = 'stereo=1;sprop-stereo=1;maxaveragebandwidth=256000;maxplaybackrate=48000';
+  for (const pt of pts) {
+    if (new RegExp(`a=fmtp:${pt} `).test(sdp)) {
+      sdp = sdp.replace(new RegExp(`a=fmtp:${pt} `), `a=fmtp:${pt} ${extra};`);
+    } else {
+      sdp = sdp.replace(new RegExp(`(a=rtpmap:${pt} opus\\/48000\\/2\\r?\\n)`), `$1a=fmtp:${pt} ${extra}\r\n`);
+    }
+  }
+  return sdp;
+}
+
+function hifiDescription(desc) {
+  if (!desc || !roomIsHifi()) return desc;
+  return { type: desc.type, sdp: mungeOpusHifi(desc.sdp) };
+}
+
 function preferOpus(pc) {
   const capabilities = globalThis.RTCRtpReceiver?.getCapabilities?.('audio');
   const codecs = capabilities?.codecs || [];
@@ -269,12 +298,12 @@ function effectiveIce() {
   return S.iceServers || FALLBACK_ICE;
 }
 
-function microphoneConstraints(deviceId = localStorage.getItem(LS_AUDIO_INPUT)) {
+function microphoneConstraints(deviceId = localStorage.getItem(LS_AUDIO_INPUT), hifi = roomIsHifi()) {
   const audio = {
-    echoCancellation: true,
+    echoCancellation: !hifi, // hi-fi rooms: raw capture — speakers may feed back, use headphones
     noiseSuppression: false,
     autoGainControl: false,
-    channelCount: 1,
+    channelCount: hifi ? 2 : 1, // ideal, not exact — mono-only mics downgrade gracefully
     sampleRate: 48000,
     sampleSize: 16,
   };
@@ -340,6 +369,9 @@ async function joinVoice(room) {
   if (S.room) leaveVoice('switching channel');
   S.connecting = true;
   setStatus(`connecting to ${room}…`, 'connecting');
+  // Hi-Fi profile must be resolved before capture: S.room still names the
+  // previous channel here, so the target room is passed explicitly.
+  const hifi = HIFI_ROOMS.has(room);
 
   // Mic permission & AudioContext: request immediately on the user-click gesture
   // so browsers don't block the microphone permission prompt or audio autoplay policy.
@@ -357,7 +389,7 @@ async function joinVoice(room) {
   window.addEventListener('keydown', resumeCtx, { passive: true });
 
   try {
-    S.rawMicStream = await navigator.mediaDevices.getUserMedia(microphoneConstraints());
+    S.rawMicStream = await navigator.mediaDevices.getUserMedia(microphoneConstraints(undefined, hifi));
     S.micStream = await S.audioManager.attachInput(S.rawMicStream);
     populateAudioInputs();
   } catch {
@@ -378,6 +410,7 @@ async function joinVoice(room) {
   S.room = room;
   S.connecting = false;
   playRetroCue('join');
+  if (hifi) toast('Hi-Fi audio on: stereo, 256 kbps, echo cancellation off — headphones recommended', 'ok');
   renderAll();
 }
 
@@ -679,7 +712,8 @@ function ensurePC(peer, initiator) {
   pc.onnegotiationneeded = async () => {
     try {
       peer.makingOffer = true;
-      await pc.setLocalDescription();
+      const offer = await pc.createOffer();
+      await pc.setLocalDescription(hifiDescription(offer));
       send({ type: 'offer', to: peer.id, sdp: pc.localDescription });
     } catch (err) {
       console.error('negotiation failed', err);
@@ -840,7 +874,8 @@ async function onDescription(peer, desc) {
     });
   }
   if (desc.type === 'offer') {
-    await pc.setLocalDescription();
+    const answer = await pc.createAnswer();
+    await pc.setLocalDescription(hifiDescription(answer));
     send({ type: 'answer', to: peer.id, sdp: pc.localDescription });
   }
 }