diff --git a/web/zebra-spaces.html b/web/zebra-spaces.html
index 5bc0e56..e3f552e 100644
--- a/web/zebra-spaces.html
+++ b/web/zebra-spaces.html
@@ -2161,7 +2161,7 @@ async function sfuPublish(){
for (const tr of micStream.getTracks()){ tagTrack(tr); pc.addTrack(tr, micStream); }
setSenderBitrate(pc.getSenders().find(s=>s.track && s.track.kind==='audio'));
const offer = await pc.createOffer();
- offer.sdp = preferStereoOpus(offer.sdp, musicMode ? 510000 : 40000, { music: musicMode });
+ offer.sdp = preferStereoOpus(offer.sdp, musicMode ? 320000 : 40000, { music: musicMode });
await pc.setLocalDescription(offer);
await waitForIceGathering(pc);
const res = await fetch(SFU_BASE + '/publish?room=' + encodeURIComponent(roomID) + '&pub=' + myKeys.pubHex, {
@@ -2251,7 +2251,7 @@ async function sfuPublishScreen(){
const offer = await pc.createOffer();
/* screen-share audio is always music-grade — system audio capture is
* what users actually broadcast, not voice */
- offer.sdp = preferStereoOpus(offer.sdp, 510000, { music: true });
+ offer.sdp = preferStereoOpus(offer.sdp, 320000, { music: true });
await pc.setLocalDescription(offer);
await waitForIceGathering(pc);
const url = SFU_BASE + '/publish?room=' + encodeURIComponent(roomID)
@@ -2271,7 +2271,7 @@ async function sfuPublishScreen(){
for (const s of pc.getSenders()){
if (!s.track) continue;
if (s.track.kind === 'video') setSenderMaxBitrate(s, 6000000);
- if (s.track.kind === 'audio') setSenderMaxBitrate(s, 510000);
+ if (s.track.kind === 'audio') setSenderMaxBitrate(s, 320000);
}
/* Screen share CANNOT auto-rebuild like mic + camera — getDisplayMedia
* requires a fresh user gesture (transient activation). Auto-calling
@@ -2343,7 +2343,7 @@ async function sfuPublishGame(iframe){
}
stream.getVideoTracks()[0].addEventListener('ended', () => { sfuUnpublishGame(); });
const offer = await pc.createOffer();
- offer.sdp = preferStereoOpus(offer.sdp, 510000, { music: true });
+ offer.sdp = preferStereoOpus(offer.sdp, 320000, { music: true });
await pc.setLocalDescription(offer);
await waitForIceGathering(pc);
const url = SFU_BASE + '/publish?room=' + encodeURIComponent(roomID)
@@ -2360,7 +2360,7 @@ async function sfuPublishGame(iframe){
for (const s of pc.getSenders()){
if (!s.track) continue;
if (s.track.kind === 'video') setSenderMaxBitrate(s, 4000000);
- if (s.track.kind === 'audio') setSenderMaxBitrate(s, 510000);
+ if (s.track.kind === 'audio') setSenderMaxBitrate(s, 320000);
}
/* game-share doesn't auto-rebuild on 'failed' — its capture source is
* a user-selected iframe via Region Capture; the user would have to
@@ -2924,7 +2924,7 @@ async function setSenderBitrate(sender){
* for transient-heavy material (orchestral, drums). 40 kbps mono is plenty
* for speech. Opus VBR only spends what it needs; idle music stays around
* 200–300 kbps and only peaks claim the ceiling. */
- p.encodings[0].maxBitrate = musicMode ? 510000 : 40000;
+ p.encodings[0].maxBitrate = musicMode ? 320000 : 40000;
await sender.setParameters(p);
} catch(_){}
}
@@ -2946,41 +2946,61 @@ async function setSenderMaxBitrate(sender, bps){
*
* Music mode also pins fullband (maxplaybackrate / sprop-maxcapturerate =
* 48000) so Opus can't opportunistically narrow to 16/24 kHz under BWE
- * pressure — and advertises NACK + maxptime:120 so receivers tolerate
- * larger frames and reactive packet recovery. cbr=0 is explicit so no
- * browser quirk silently flips us to constant-rate. */
+ * pressure. NACK is gated by RTCRtpSender.getCapabilities so each browser
+ * only advertises what it can back up. cbr=0 is explicit so no browser
+ * quirk silently flips us to constant-rate. */
function preferStereoOpus(sdp, maxAvgBps, opts){
const music = !!(opts && opts.music);
/* DTX is great for voice (silence is silence) but its comfort-noise
* transitions audibly pop on continuous music signals — keep it OFF
* in music mode and ON for voice. */
const dtx = music ? '0' : '1';
- let opusPT = null;
- sdp = sdp.replace(/a=fmtp:(\d+) ([^\r\n]*minptime=10[^\r\n]*)/g, (m, pt, fmtp) => {
- opusPT = pt;
- /* useinbandfec=1: forward error correction so a single dropped
- * packet doesn't audibly chop — Opus reconstructs from FEC.
- * maxplaybackrate / sprop-maxcapturerate=48000: fullband both ways.
- * cbr=0: explicit VBR. Opus VBR only spends what it needs; the high
- * ceiling is just headroom for transients, not a constant load. */
- const want = {
- 'stereo': '1', 'sprop-stereo': '1',
- 'maxaveragebitrate': String(maxAvgBps),
- 'useinbandfec': '1', 'usedtx': dtx,
- 'maxplaybackrate': '48000', 'sprop-maxcapturerate': '48000',
- 'cbr': '0',
- };
- const parts = fmtp.split(';').map(s => s.trim()).filter(Boolean);
- const seen = new Set();
- for (let i = 0; i < parts.length; i++){
- const k = parts[i].split('=')[0];
- seen.add(k);
- if (want[k] !== undefined) parts[i] = k + '=' + want[k];
+ /* Find every Opus payload type from rtpmap. Anchoring on minptime=10
+ * (as we used to) silently no-op'd on Firefox publishers, because
+ * Firefox emits `a=fmtp:109 maxplaybackrate=48000;stereo=1;useinbandfec=1`
+ * with no minptime — the entire music-mode SDP munge was skipped on FF
+ * for years. rtpmap is reliably present for every negotiated codec. */
+ const opusPTs = [];
+ const rtpmapRe = /a=rtpmap:(\d+) opus\/48000\/2/gi;
+ let mm;
+ while ((mm = rtpmapRe.exec(sdp)) !== null) opusPTs.push(mm[1]);
+ if (!opusPTs.length) return sdp;
+ /* useinbandfec=1: forward error correction so a single dropped
+ * packet doesn't audibly chop — Opus reconstructs from FEC.
+ * maxplaybackrate / sprop-maxcapturerate=48000: fullband both ways.
+ * cbr=0: explicit VBR. Opus VBR only spends what it needs; the high
+ * ceiling is just headroom for transients, not a constant load. */
+ const want = {
+ 'stereo': '1', 'sprop-stereo': '1',
+ 'maxaveragebitrate': String(maxAvgBps),
+ 'useinbandfec': '1', 'usedtx': dtx,
+ 'maxplaybackrate': '48000', 'sprop-maxcapturerate': '48000',
+ 'cbr': '0',
+ };
+ for (const pt of opusPTs){
+ const fmtpRe = new RegExp('a=fmtp:' + pt + ' ([^\\r\\n]*)', 'g');
+ if (fmtpRe.test(sdp)){
+ /* update existing fmtp params in place */
+ sdp = sdp.replace(new RegExp('a=fmtp:' + pt + ' ([^\\r\\n]*)', 'g'), (_, fmtp) => {
+ const parts = fmtp.split(';').map(s => s.trim()).filter(Boolean);
+ const seen = new Set();
+ for (let i = 0; i < parts.length; i++){
+ const k = parts[i].split('=')[0];
+ seen.add(k);
+ if (want[k] !== undefined) parts[i] = k + '=' + want[k];
+ }
+ for (const k of Object.keys(want)) if (!seen.has(k)) parts.push(k + '=' + want[k]);
+ return 'a=fmtp:' + pt + ' ' + parts.join(';');
+ });
+ } else {
+ /* no fmtp line exists for this PT — insert one right after rtpmap */
+ const parts = Object.keys(want).map(k => k + '=' + want[k]);
+ sdp = sdp.replace(
+ new RegExp('(a=rtpmap:' + pt + ' opus[^\\r\\n]*\\r?\\n)', 'i'),
+ '$1a=fmtp:' + pt + ' ' + parts.join(';') + '\r\n'
+ );
}
- for (const k of Object.keys(want)) if (!seen.has(k)) parts.push(k + '=' + want[k]);
- return 'a=fmtp:' + pt + ' ' + parts.join(';');
- });
- if (!opusPT) return sdp;
+ }
/* Audio NACK is asymmetric — the SENDER has to respond to retransmit
* requests. Chrome implements both sides; Firefox implements neither
* for audio (Mozilla never shipped it). Blanket-advertising NACK in
@@ -2995,19 +3015,19 @@ function preferStereoOpus(sdp, maxAvgBps, opts){
* Each browser only offers what it can back up. No LCD across the
* room, no per-peer signaling needed — the SDP itself is honest. */
if (senderSupportsAudioNack()){
- const nackLine = 'a=rtcp-fb:' + opusPT + ' nack';
- if (sdp.indexOf(nackLine) === -1){
- sdp = sdp.replace(new RegExp('(a=rtpmap:' + opusPT + ' opus[^\\r\\n]*\\r?\\n)'),
- '$1' + nackLine + '\r\n');
+ for (const pt of opusPTs){
+ const nackLine = 'a=rtcp-fb:' + pt + ' nack';
+ if (sdp.indexOf(nackLine) === -1){
+ sdp = sdp.replace(new RegExp('(a=rtpmap:' + pt + ' opus[^\\r\\n]*\\r?\\n)', 'i'),
+ '$1' + nackLine + '\r\n');
+ }
}
}
- /* Tolerate larger frames from peers (up to 120ms). Bigger encode
- * windows give Opus more context per packet → cleaner music at the
- * same bitrate. We can't force OUR encoder's frame size from JS but
- * advertising the tolerance keeps the negotiation open. */
- if (music && !/a=maxptime:/.test(sdp)){
- sdp = sdp.replace(/(a=rtpmap:\d+ opus[^\r\n]*\r?\n)/, '$1a=maxptime:120\r\n');
- }
+ /* maxptime advertisement removed: tried a=maxptime:120 to encourage
+ * larger encode windows, but Chrome publishers under it produced choppy
+ * playback on receivers (likely the encoder actually packed at higher
+ * ptime and the receiver's jitter buffer / playoutDelayHint=0.7 didn't
+ * keep up). Default 20ms packetization stays. */
return sdp;
}
/* Probe the local browser's audio sender capabilities — does Opus
@@ -3822,7 +3842,7 @@ async function connectToPeer(uuid, weOffer){
};
if (weOffer){
const offer = await pc.createOffer();
- offer.sdp = preferStereoOpus(offer.sdp, musicMode ? 510000 : 40000, { music: musicMode });
+ offer.sdp = preferStereoOpus(offer.sdp, musicMode ? 320000 : 40000, { music: musicMode });
await pc.setLocalDescription(offer);
await waitForIceGathering(pc);
await sendEncSDP(uuid, 'offer', pc.localDescription);
@@ -4447,8 +4467,8 @@ logLine('', 'ready — pick a handle, type a rendezvous code, enter the space');