diff --git a/plugins/objectdetector/package-lock.json b/plugins/objectdetector/package-lock.json
index 6666d048d..bd822523d 100644
--- a/plugins/objectdetector/package-lock.json
+++ b/plugins/objectdetector/package-lock.json
@@ -1,12 +1,12 @@
 {
    "name": "@scrypted/objectdetector",
-   "version": "0.0.46",
+   "version": "0.0.47",
    "lockfileVersion": 2,
    "requires": true,
    "packages": {
       "": {
          "name": "@scrypted/objectdetector",
-         "version": "0.0.46",
+         "version": "0.0.47",
          "license": "Apache-2.0",
          "dependencies": {
             "@scrypted/common": "file:../../common",
diff --git a/plugins/objectdetector/package.json b/plugins/objectdetector/package.json
index 1db66b715..58968457e 100644
--- a/plugins/objectdetector/package.json
+++ b/plugins/objectdetector/package.json
@@ -1,6 +1,6 @@
 {
    "name": "@scrypted/objectdetector",
-   "version": "0.0.46",
+   "version": "0.0.47",
    "description": "Scrypted Video Analysis Plugin. Installed alongside a detection service like OpenCV or TensorFlow.",
    "author": "Scrypted",
    "license": "Apache-2.0",
diff --git a/plugins/objectdetector/src/denoise.ts b/plugins/objectdetector/src/denoise.ts
index 8c55f4d58..dcf64dadf 100644
--- a/plugins/objectdetector/src/denoise.ts
+++ b/plugins/objectdetector/src/denoise.ts
@@ -2,7 +2,7 @@ export class DenoisedDetectionEntry<T> {
     id: string;
     name: string;
     detection: T;
-    timeout?: NodeJS.Timeout;
+    lastSeen: number;
 }
 
 export interface DenoisedDetectionOptions<T> {
@@ -15,6 +15,7 @@ export function denoiseDetections<T>(previousDetections: DenoisedDetectionEntry<
     currentDetections: DenoisedDetectionEntry<T>[],
     options?: DenoisedDetectionOptions<T>
 ) {
+    const now = Date.now();
     const newAndExisting: DenoisedDetectionEntry<T>[] = [];
     for (const cd of currentDetections) {
         let index = -1;
@@ -28,24 +29,20 @@ export function denoiseDetections<T>(previousDetections: DenoisedDetectionEntry<
         }
         else {
             const [found] = previousDetections.splice(index, 1);
-            if (found.timeout) {
-                clearTimeout(found.timeout);
-                found.timeout = undefined;
-            }
+            found.lastSeen = now;
             newAndExisting.push(cd);
         }
     }
 
+    const purgeTime = options?.timeout || 10000;
     // anything remaining in previousDetections at this point has possibly left the scene.
-    for (const cd of previousDetections) {
-        if (!cd.timeout) {
-            cd.timeout = setTimeout(() => {
-                const index = previousDetections.findIndex(check => check === cd);
-                if (index !== -1)
-                    previousDetections.splice(index, 1);
-                options?.removed?.(cd);
-            }, options?.timeout || 10000);
-        }
+    for (const cd of previousDetections.slice()) {
+        if (now - cd.lastSeen < purgeTime)
+            continue;
+        const index = previousDetections.findIndex(check => check === cd);
+        if (index !== -1)
+            previousDetections.splice(index, 1);
+        options?.removed?.(cd);
     }
 
     // add all the detections that are pending removal
diff --git a/plugins/objectdetector/src/main.ts b/plugins/objectdetector/src/main.ts
index 3993850b4..c2ac30289 100644
--- a/plugins/objectdetector/src/main.ts
+++ b/plugins/objectdetector/src/main.ts
@@ -220,6 +220,8 @@ class ObjectDetectionMixin extends SettingsMixinDeviceBase<VideoCamera & Camera
       if (!this.internal) {
         stream = await this.cameraDevice.getVideoStream({
           destination: 'low-resolution',
+          // request no prebuffer because it will throw off detection timestamps.
+          prebuffer: 0,
         });
       }
       else {
@@ -250,6 +252,34 @@ class ObjectDetectionMixin extends SettingsMixinDeviceBase<VideoCamera & Camera
     if (detectionInput)
       this.setDetection(this.detectionId, detectionInput);
 
+    // determine zones of the objects, if configured.
+    if (detection.detections && Object.keys(this.zones).length) {
+      for (const o of detection.detections) {
+        if (!o.boundingBox)
+          continue;
+        o.zones = []
+        let [x, y, width, height] = o.boundingBox;
+        let x2 = x + width;
+        let y2 = y + height;
+        // the zones are point paths in percentage format
+        x = x * 100 / detection.inputDimensions[0];
+        y = y * 100 / detection.inputDimensions[1];
+        x2 = x2 * 100 / detection.inputDimensions[0];
+        y2 = y2 * 100 / detection.inputDimensions[1];
+        const box = [[x, y], [x2, y], [x2, y2], [x, y2]];
+        for (const [zone, zoneValue] of Object.entries(this.zones)) {
+          if (polygonOverlap(box, zoneValue)) {
+            this.console.log(o.className, 'inside', zone);
+            o.zones.push(zone);
+          }
+        }
+      }
+    }
+
+    // if this detector supports bounding boxes, and there are zones configured,
+    // filter the detections to the zones.
+    detection.detections = detection.detections.filter(o => !o.boundingBox || o?.zones?.length);
+
     if (this.hasMotionType) {
       const found = detection.detections?.find(d => d.className === 'motion');
       if (found) {
@@ -263,35 +293,8 @@ class ObjectDetectionMixin extends SettingsMixinDeviceBase<VideoCamera & Camera
       }
     }
 
-    if (!this.hasMotionType || this.motionAsObjects) {
-      if (detection.detections && Object.keys(this.zones).length) {
-        for (const o of detection.detections) {
-          if (!o.boundingBox)
-            continue;
-          o.zones = []
-          let [x, y, width, height] = o.boundingBox;
-          let x2 = x + width;
-          let y2 = y + height;
-          // the zones are point paths in percentage format
-          x = x * 100 / detection.inputDimensions[0];
-          y = y * 100 / detection.inputDimensions[1];
-          x2 = x2 * 100 / detection.inputDimensions[0];
-          y2 = y2 * 100 / detection.inputDimensions[1];
-          const box = [[x, y], [x2, y], [x2, y2], [x, y2]];
-          for (const [zone, zoneValue] of Object.entries(this.zones)) {
-            if (polygonOverlap(box, zoneValue)) {
-              this.console.log(o.className, 'inside', zone);
-              o.zones.push(zone);
-            }
-          }
-        }
-
-        // if this detector supports bounding boxes, and there are zones configured,
-        // filter the detections to the zones.
-        detection.detections = detection.detections.filter(o => !o.boundingBox || o?.zones?.length);
-      }
+    if (!this.hasMotionType || this.motionAsObjects)
       this.onDeviceEvent(ScryptedInterface.ObjectDetector, detection);
-    }
   }
 
   async extendedObjectDetect() {
@@ -324,6 +327,7 @@ class ObjectDetectionMixin extends SettingsMixinDeviceBase<VideoCamera & Camera
       id: detection.id,
       name: detection.className,
       detection,
+      lastSeen: detectionResult.timestamp,
     })), {
       timeout: this.detectionTimeout * 1000,
       added: d => found.push(d),