From 60615a2e73d084e6297d8127045f63e52b314791 Mon Sep 17 00:00:00 2001
From: Russell Ballestrini <russell.ballestrini@gmail.com>
Date: Thu, 28 May 2026 17:38:41 -0400
Subject: [PATCH] =?UTF-8?q?zebra-audio:=20music=20mode=20=E2=80=94=20disab?=
 =?UTF-8?q?le=20voice=20isolation=20for=20playing=20audio?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Add a "music mode" toggle that re-acquires the mic with echo cancellation,
noise suppression, and auto-gain OFF (so music/audio passes through instead of
being treated as noise and pumped), tags the track contentHint='music' so the
Opus encoder drops speech optimizations (DTX etc.), and raises the send bitrate.
Switchable mid-call via replaceTrack — hot-swaps the track with no
renegotiation, preserving mute state. Verified mid-call switch stays connected
both directions.
---
 web/zebra-audio.html | 49 +++++++++++++++++++++++++++++++++++++++-----
 1 file changed, 44 insertions(+), 5 deletions(-)

diff --git a/web/zebra-audio.html b/web/zebra-audio.html
index 5d3e2d7..d1c0a33 100644
--- a/web/zebra-audio.html
+++ b/web/zebra-audio.html
@@ -88,6 +88,9 @@
     <div class="dot" id="dot-path"></div>
     <span id="path-status" class="status-line">path: —</span>
   </div>
+  <div class="row">
+    <label class="note"><input type="checkbox" id="music-mode"> music mode — raw mic, no echo/noise cancellation (for playing audio through it)</label>
+  </div>
   <p class="note">
     both partners type the same code and hit call. audio is end-to-end
     encrypted (DTLS-SRTP), peer-to-peer when the network allows, relayed through
@@ -173,14 +176,44 @@ async function refreshTurnCred(){
 }
 
 /* ---- audio ---- */
-let micStream = null, audioCtx = null;
+let micStream = null, audioCtx = null, musicMode = false;
+/* voice mode = echo-cancel + noise-suppress + auto-gain (clean speech).
+ * music mode = all of that OFF so music/audio passes through un-mangled. */
+function micConstraints(){
+  return musicMode
+    ? { echoCancellation:false, noiseSuppression:false, autoGainControl:false }
+    : { echoCancellation:true,  noiseSuppression:true,  autoGainControl:true  };
+}
+function tagTrack(t){ if (t) t.contentHint = musicMode ? 'music' : 'speech'; }
+async function setSenderBitrate(sender){
+  if (!sender) return;
+  try {
+    const p = sender.getParameters();
+    if (!p.encodings || !p.encodings.length) p.encodings = [{}];
+    p.encodings[0].maxBitrate = musicMode ? 160000 : 40000;   /* bits/s */
+    await sender.setParameters(p);
+  } catch(_){}
+}
 async function getMic(){
   if (micStream) return micStream;
-  micStream = await navigator.mediaDevices.getUserMedia({
-    audio: { echoCancellation:true, noiseSuppression:true, autoGainControl:true }, video:false
-  });
+  micStream = await navigator.mediaDevices.getUserMedia({ audio: micConstraints(), video:false });
+  tagTrack(micStream.getAudioTracks()[0]);
   return micStream;
 }
+/* switch voice<->music mid-call: re-acquire the mic and hot-swap the track on
+ * the live connection (no renegotiation), preserving mute state */
+async function applyMicMode(){
+  const ns = await navigator.mediaDevices.getUserMedia({ audio: micConstraints(), video:false });
+  const nt = ns.getAudioTracks()[0];
+  tagTrack(nt); nt.enabled = !muted;
+  if (pc){
+    const sender = pc.getSenders().find(s=>s.track && s.track.kind==='audio') || pc.getSenders()[0];
+    if (sender){ try { await sender.replaceTrack(nt); } catch(_){} setSenderBitrate(sender); }
+  }
+  if (micStream) micStream.getTracks().forEach(t=>t.stop());
+  micStream = ns;
+  meterFor(micStream, 'meter-mic');
+}
 function meterFor(stream, fillId){
   if (!audioCtx) audioCtx = new (window.AudioContext||window.webkitAudioContext)();
   const src = audioCtx.createMediaStreamSource(stream);
@@ -214,7 +247,8 @@ function setPath(msg, cls){ const e=$('path-status'); e.textContent=msg; e.class
 async function ensurePC(){
   if (pc) return pc;
   pc = new RTCPeerConnection(rtcConfig);
-  for (const tr of micStream.getTracks()) pc.addTrack(tr, micStream);
+  for (const tr of micStream.getTracks()) { tagTrack(tr); pc.addTrack(tr, micStream); }
+  setSenderBitrate(pc.getSenders().find(s=>s.track && s.track.kind==='audio'));
   pc.ontrack = (ev) => {
     const stream = ev.streams[0] || new MediaStream([ev.track]);
     $('remote-audio').srcObject = stream;
@@ -353,6 +387,11 @@ $('btn-call').addEventListener('click', startCall);
 $('btn-hangup').addEventListener('click', hangup);
 $('btn-mute').addEventListener('click', toggleMute);
 $('rdv-code').addEventListener('keydown', e=>{ if(e.key==='Enter'){ e.preventDefault(); startCall(); } });
+$('music-mode').addEventListener('change', async (e)=>{
+  musicMode = e.target.checked;
+  logLine('', 'mic mode: '+(musicMode?'MUSIC — raw, no voice isolation':'VOICE — echo/noise cancel'));
+  if (micStream){ try { await applyMicMode(); } catch(err){ logLine('err','mic mode switch failed: '+err.message); } }
+});
 logLine('', 'ready — type a rendezvous code and call. mic stays muted to the room until connected.');
 })();
 </script>