diff --git a/event/stream/topics.go b/event/stream/topics.go
index 552c132..1345233 100644
--- a/event/stream/topics.go
+++ b/event/stream/topics.go
@@ -79,7 +79,14 @@ var topicRules = []struct {
 	// https://developer.axis.com/vapix/network-video/event-and-action-services/
 	{"MotionRegionDetector/Motion", KindMotion},
 
-	// AXIS ACAP motion apps with Camera<N>Profile<ID> suffixes. VMD is
+	// tns1:RuleEngine/tnsaxis:VMD3/vmd3_video_<N> — AXIS VMD 3, the
+	// firmware-builtin predecessor of the VMD 4 ACAP. It lives under
+	// RuleEngine, not CameraApplicationPlatform, so the VMD rule below
+	// does not cover it. Still shipping on deployed cameras.
+	// https://developer.axis.com/vapix/network-video/event-and-action-services/
+	{"RuleEngine/VMD3/", KindMotion},
+
+	// AXIS ACAP motion apps with Camera<N>Profile<ID> suffixes. VMD 4 is
 	// the stock app shipped on the camera; the Guard suite are the
 	// paid analytics products. Prefix-match because of the suffix.
 	// https://developer.axis.com/vapix/applications/vmd4
diff --git a/event/stream/topics_test.go b/event/stream/topics_test.go
index 617bf5b..8e12e26 100644
--- a/event/stream/topics_test.go
+++ b/event/stream/topics_test.go
@@ -31,6 +31,12 @@ func TestClassifyTopic(t *testing.T) {
 		{"axis_vmd4_profile_any", "tnsaxis:CameraApplicationPlatform/VMD/Camera1ProfileANY", KindMotion},
 		{"axis_vmd4_profile_numbered", "tnsaxis:CameraApplicationPlatform/VMD/Camera1Profile1", KindMotion},
 
+		// AXIS VMD 3 — the firmware-builtin predecessor, published under
+		// RuleEngine rather than CameraApplicationPlatform. Still shipping
+		// on deployed cameras; observed on site-07 camera-10.
+		{"axis_vmd3_video_1", "tns1:RuleEngine/tnsaxis:VMD3/vmd3_video_1", KindMotion},
+		{"axis_vmd3_video_2", "tns1:RuleEngine/tnsaxis:VMD3/vmd3_video_2", KindMotion},
+
 		// --- Tampering --------------------------------------------------
 
 		{"tamper_detector", "tns1:RuleEngine/TamperDetector/Tamper", KindTampering},