From 6fd5b136b6ce79ae62ac841f2c8ea045d746513d Mon Sep 17 00:00:00 2001
From: patrykorwat <patrykorwat@gmail.com>
Date: Fri, 21 Aug 2026 06:08:17 +0000
Subject: [PATCH] fix(axelera): stop keep-alive frames after pipeline init

Misattribution reproduced at night: when Frigate stops sending frames
during quiet periods the queue empties and keep-alive frames are emitted;
a pending real-frame result then races the keep-alive's (empty) result,
which steals the real id (frame/detections shown under the WRONG camera).

Fix: synthesize keep-alive frames ONLY until the first stream result
(_primed), then never again - no unregistered result can exist in the
pipeline afterwards. Queue-empty after init just waits; under Frigate's
continuous feed this branch is only hit during true quiet periods, where
there is no pending request to misattribute anyway.
---
 frigate/detectors/plugins/axelera.py | 23 +++++++++++++++++++----
 1 file changed, 19 insertions(+), 4 deletions(-)

diff --git a/frigate/detectors/plugins/axelera.py b/frigate/detectors/plugins/axelera.py
index e3ea5436e7..cf990f8dfa 100644
--- a/frigate/detectors/plugins/axelera.py
+++ b/frigate/detectors/plugins/axelera.py
@@ -153,6 +153,11 @@ class _AxeleraInference:
         # flight the FIFO pop can misattribute a result to the wrong camera.
         # With at most one frame in flight the result can only belong to it.
         self._run_lock = threading.Lock()
+        # Set on the FIRST stream result. Until then the feed may synthesize
+        # keep-alive frames so the SDK pipeline finishes initializing; after
+        # this NO synthetic frames are ever emitted, so an unregistered result
+        # can never arrive while a real request id is pending.
+        self._primed = threading.Event()
 
         if stream_factory is None:
             # lazy import: never import the SDK unless the detector is used
@@ -187,9 +192,16 @@ class _AxeleraInference:
             try:
                 frame_id, frame = self._frame_q.get(timeout=1.0)
             except queue.Empty:
-                # keep-alive: no request pending, keep the SDK stream fed so the
-                # inference timeout never kills it during quiet periods. The
-                # None id means this frame's result is dropped by the pump.
+                if self._primed.is_set():
+                    # After init NEVER synthesize frames: a keep-alive result
+                    # can arrive while a real id is pending and steal it
+                    # (misattribution across cameras, observed at night when
+                    # Frigate stops sending frames during quiet periods).
+                    time.sleep(0.2)
+                    continue
+                # During pipeline init the SDK needs a sustained source; these
+                # zero frames prime it and are drained before the first real
+                # request is registered.
                 frame_id, frame = None, np.zeros(
                     (self._height, self._width, 3), np.uint8
                 )
@@ -255,8 +267,11 @@ class _AxeleraInference:
         logger.info("axelera: inference stream started")
         try:
             for frame_result in self._stream:
+                if not self._primed.is_set():
+                    self._primed.set()
+                    logger.info("axelera: pipeline initialized (first result)")
                 out = _pad_rows(self._detection_rows(frame_result))
-                if self._pending_ids:
+                if self._primed.is_set() and self._pending_ids:
                     # FIFO: the stream returns results in submission order, so
                     # the oldest pending id belongs to this result.
                     frame_id = self._pending_ids.popleft()