CLAUDE.md: chrome decoder anchor + always-SFU receive + telemetry + tickets

- SPEAKER_PLAYOUT_DELAY_SEC bumped to 0.7s; mesh peers no longer
  carry inbound audio so the worklet cushion absorbs host-wiggle
  on the SFU path unaided.
- New "Chromium decoder anchor" section pins the load-bearing
  hidden muted <audio> requirement so a future refactor can't
  silently remove it.
- New "Audio receive path — SFU only" section documents the
  always-SFU contract + ground rules for any future mesh
  reintroduction.
- New "Telemetry — signal-server CLIENT_LOG" section documents
  how to grep /var/log/zebra-spaces-signal.log via SSH, the
  per-tick line shape, the one-shot session fingerprint, and the
  per-service /version endpoints on cors-proxy.uncloseai.com.
- New "Defect tracking — docs/tickets/" section documents the
  resolution loop (telemetry → failing test → fix → stamp →
  deploy → close).
This commit is contained in:
Russell Ballestrini 2026-06-07 20:13:53 -04:00
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CLAUDE.md
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@ -280,10 +280,11 @@ Rules that took blood to find:
rearmThresholdBlocks=100`) before re-arming; emit silence in the interim.
2. **Role-aware buffer depth.** Listener gets 4s (lean-back, latency doesn't
matter, ride out wiggle-stalls). Speaker / cohost / host get 0.5s (small
enough for conversation, big enough to smooth ordinary jitter). Mesh
peers always 0.5s. `playoutDelayForRole(role)` and `SPEAKER_PLAYOUT_DELAY_SEC`
in `web/zebra-spaces.html`.
matter, ride out wiggle-stalls). Speaker / cohost / host get **0.7s**
(`SPEAKER_PLAYOUT_DELAY_SEC` in `web/zebra-spaces.html` — bumped from
0.5s when we removed the mesh→worklet swap; the worklet cushion now
absorbs the 200ms host-wiggle unaided on the SFU receive path).
`playoutDelayForRole(role)` returns the active target.
3. **Worklet retarget on role change**, don't rebuild. Post
`{cmd:'retarget', targetSeconds}` to the worklet's port — recomputes
@ -315,3 +316,97 @@ who don't have AudioWorklet support — natural deep buffer on the
`<audio>` preload side. Was deadlocking on `bcastMu` until 2026-06-04
(commit fixed `bcastInitCapture.Write` self-recursion). Worklet is the
primary path; HTTP-pull is the safety net.
### Chromium decoder anchor — required for remote audio tracks
**Every remote `MediaStreamTrack` consumed by a
`MediaStreamAudioSourceNode` must ALSO be attached to a hidden muted
`<audio>` element in the same page.** Without that anchor, chromium
does NOT run its WebRTC audio decoder for the track, and the source
node produces silence — even though packets arrive at full rate,
`audioCtx.state === 'running'`, and the worklet's `started` event
fires (queue filled with zeros).
Firefox does NOT have this restriction. Defects of this shape present
as **chrome-only silence with every JS-side invariant green**.
The anchor lives on the `listenerAudioNodes` entry as `node.anchor`
(see `attachAudioStreamViaWorklet`). It is muted, hidden, and
autoplays. `setWorkletStream` swaps `anchor.srcObject` alongside the
source node. `detachListenerStream` tears the anchor down.
Diagnostic signal: pavucontrol Playback shows the chrome stream
present, level meter pinned at 0 while RTP telemetry shows
`aud.recv pkt=N → N+50/sec bytes=growing level=0.000 jbuf=?` and
worklet `started` event has fired. → anchor is the load-bearing
fix. Do NOT remove it during a refactor.
Full root-cause writeup: `docs/tickets/0001-fedora-chrome-cannot-hear-speakers.md`.
Memory: `feedback-chromium-decoder-anchor`.
### Audio receive path — SFU only
**SFU is the only receive-audio path for every role**, including
speakers. Mesh PCs (`peers` map) carry our OUTBOUND mic only. Their
inbound audio is ignored (`pc.ontrack` in `connectToPeer` is a
breadcrumb log only).
This is a 2026-06-07 change. The previous mesh→worklet swap caused
chromium decoders to silently stall at the source-swap moment. The
0.5s → 0.7s `SPEAKER_PLAYOUT_DELAY_SEC` bump compensates for the lost
mesh latency benefit by giving the worklet enough cushion to absorb
the 200ms host-wiggle on the SFU path.
If you reintroduce a mesh receive path, the right shape is
verify-before-swap (poll mesh receiver stats for
`jitterBufferEmittedCount > 0` BEFORE disconnecting the SFU source).
### Telemetry — signal-server CLIENT_LOG
Every `logLine` call in `web/zebra-spaces.html` ships to the
zebra-spaces-signal server as a `client-log` WebSocket message. The
server logs to `/var/log/zebra-spaces-signal.log` on
proxy.uncloseai.com with the publisher's pubkey + handle attached.
Diagnostic SSH (read-only):
```bash
ssh -i ~/.ssh/digitalocean -p 22222 root@proxy.uncloseai.com \
'tail -2000 /var/log/zebra-spaces-signal.log | grep "actor_handle=\"HANDLE\""'
```
Per-tick (~5s) telemetry line shape:
```
· role=X sub=X/X pub=X/X mesh=N sListen=N streamMode=N muted=X xcr=X ctx.sink=…
aud.recv pkt=N lost=N bytes=N jitter=N level=N jbuf=Xs lp=Xs (per SFU sub PC audio receiver)
vid.recv pkt=N lost=N frames=N jbuf=Xs lp=Xs (per SFU sub PC video receiver)
mesh.recv u=XXXX pkt=N … level=N jbuf=Xs (per mesh PC audio receiver)
mic.send.aud / cam.send.vid / scr.send.vid / etc. (outbound stats per publish PC)
```
One-shot session fingerprint on entry (after `joined as X — uuid …`):
```
session: ua=chrome/desktop ctx={sr=48000 baseLat=0.0107 sinkSupp=1 sink=…}
devs={out=N in=N cam=N} picked={mic=… cam=… spk=…}
```
The signal-server endpoint backs `cors-proxy.uncloseai.com`. Per-service
`/version` is exposed at `/zebra-spaces-signal/version` /
`/zebra-spaces-sfu/version` / `/zebra-signal/version` / `/version` (each
returns the upstream Go binary's commit + build_time).
### Defect tracking — docs/tickets/
Anything that takes more than 15 minutes or needs cross-browser /
cross-session repro lives as a numbered markdown file under
`docs/tickets/`. Format spec + index in `docs/tickets/README.md`. New
tickets get the next number. The resolution loop is:
1. Reproduce or grab signal-server telemetry.
2. Write a failing test in `test/` that pins the contract.
3. Fix until test passes.
4. `make stamp`, push both repos.
5. Update ticket Status to `fixed`, link commit, note what to
re-test in production.