A Hikvision DS-2CD1047G3H-LIU returned HTTP 503 (statusCode 2 / deviceBusy)
on EVERY main-stream snapshot — its main encoder is persistently saturated.
Probed on hardware: channels/101/picture → 503 on 5 consecutive tries, while
channels/102/picture (sub stream) → 200 clean JPEG every time. A retry loop
can't fix a persistent busy; the real fix is stream selection.
- Add a `stream` config field to the Hikvision driver (1=main, default for
back-compat; 2=sub). ISAPI channel id is <channel><stream> (101 main, 102 sub).
Verified live: setting the G3H to Sub flips its status degraded→ready (14.7KB
JPEG in ~87ms).
- captureSnapshot also retries the TRANSIENT case (503/500, linear backoff
250/500/750ms ×4) then fails naming it "(device busy)"; does NOT retry 401/404
(config errors won't self-heal). Complements captureSnapshotShared (concurrent
de-dup). healthCheck still reports a live 503 as degraded (surfaces a saturated
main stream rather than hiding it).
Tests: camera.test.ts (10) — retry behaviour + main/sub path selection.
Claude-Session: https://claude.ai/code/session_01Xcm6ikLgGoCxxHrxtjkk5V
julian
f0fd15bb88