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zebra-spaces: applyConstraints + log effective mic settings — surfaces hidden filtering

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When a PulseAudio monitor source is selected as the mic and music mode
is toggled on, Firefox can silently apply its default audio-processing
pipeline (EC/NS/AGC) regardless of the getUserMedia constraints. The
broadcast then sounds 'cleaned up' instead of letting the source pass
through transparently.

Two fixes:
- call track.applyConstraints(micConstraints()) after getUserMedia/replace.
  Some UAs honour applyConstraints when they silently ignored the initial
  request. Belt-and-suspenders.
- log track.getSettings() so we can see what the UA actually applied —
  ec/ns/agc/channels/sampleRate. If applyConstraints didn't stick, the
  log shows it instead of failing silently.
This commit is contained in:
Russell Ballestrini 2026-06-01 20:33:41 -04:00
parent 1294e96f01
commit 3f43379e00
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1 changed files with 22 additions and 3 deletions
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25
web/zebra-spaces.html
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@ -946,10 +946,28 @@ async function refreshMicList(){
} catch(e){ logLine('err','could not list inputs: '+e.message); }
}
function tagTrack(t){ if (t) t.contentHint = musicMode ? 'music' : 'speech'; }
/* Firefox sometimes ignores the EC/NS/AGC constraints at getUserMedia time
* for non-mic sources (e.g. PulseAudio monitor) and applies its default
* processing pipeline anyway. applyConstraints() after the fact tends to
* stick. Log the actual settings so we can see what the UA ended up with —
* silent disagreement between requested and effective constraints is what
* makes music-mode-on-a-monitor-source sound 'cleaned up'. */
async function enforceMicConstraints(track){
if (!track) return;
try { await track.applyConstraints(micConstraints()); } catch(e){ logLine('', 'applyConstraints rejected: '+e.message); }
try {
const s = track.getSettings();
logLine('', 'mic track settings: '+JSON.stringify({
ec: s.echoCancellation, ns: s.noiseSuppression, agc: s.autoGainControl,
ch: s.channelCount, hz: s.sampleRate, dev: (s.deviceId||'').slice(0,8)
}));
} catch(_){}
}
async function getMic(){
if (micStream) return micStream;
micStream = await navigator.mediaDevices.getUserMedia({ audio: micConstraints(), video:false });
tagTrack(micStream.getAudioTracks()[0]);
const t = micStream.getAudioTracks()[0];
tagTrack(t); await enforceMicConstraints(t);
return micStream;
}
async function setSenderBitrate(sender){
@ -998,6 +1016,7 @@ async function applyMicMode(){
const ns = await navigator.mediaDevices.getUserMedia({ audio: micConstraints(), video:false });
const nt = ns.getAudioTracks()[0];
tagTrack(nt); nt.enabled = !muted;
await enforceMicConstraints(nt);
async function swap(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); }
@ -1707,8 +1726,8 @@ logLine('', 'ready — pick a handle, type a rendezvous code, enter the space');
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