feat: add X-Frame-Time when returning snapshot (#21932)

Co-authored-by: Florent MORICONI <170678386+fmcloudconsulting@users.noreply.github.com>

frigate/api/media.py

@@ -761,7 +761,7 @@ async def event_snapshot(
                 if event_id in camera_state.tracked_objects:
                     tracked_obj = camera_state.tracked_objects.get(event_id)
                     if tracked_obj is not None:
-                        jpg_bytes = tracked_obj.get_img_bytes(
+                        jpg_bytes, frame_time = tracked_obj.get_img_bytes(
                             ext="jpg",
                             timestamp=params.timestamp,
                             bounding_box=params.bbox,
@@ -790,6 +790,7 @@ async def event_snapshot(
     headers = {
         "Content-Type": "image/jpeg",
         "Cache-Control": "private, max-age=31536000" if event_complete else "no-store",
+        "X-Frame-Time": frame_time,
     }
 
     if params.download:

frigate/track/object_processing.py

@@ -185,7 +185,7 @@ class TrackedObjectProcessor(threading.Thread):
         def snapshot(camera: str, obj: TrackedObject) -> bool:
             mqtt_config: CameraMqttConfig = self.config.cameras[camera].mqtt
             if mqtt_config.enabled and self.should_mqtt_snapshot(camera, obj):
-                jpg_bytes = obj.get_img_bytes(
+                jpg_bytes, _ = obj.get_img_bytes(
                     ext="jpg",
                     timestamp=mqtt_config.timestamp,
                     bounding_box=mqtt_config.bounding_box,

frigate/track/tracked_object.py

@@ -434,7 +434,7 @@ class TrackedObject:
         return count > (self.camera_config.detect.stationary.threshold or 50)
 
     def get_thumbnail(self, ext: str) -> bytes | None:
-        img_bytes = self.get_img_bytes(
+        img_bytes, _ = self.get_img_bytes(
             ext, timestamp=False, bounding_box=False, crop=True, height=175
         )
 
@@ -475,20 +475,21 @@ class TrackedObject:
         crop: bool = False,
         height: int | None = None,
         quality: int | None = None,
-    ) -> bytes | None:
+    ) -> tuple[bytes | None, float | None]:
         if self.thumbnail_data is None:
-            return None
+            return None, None
 
         try:
+            frame_time = self.thumbnail_data["frame_time"]
             best_frame = cv2.cvtColor(
-                self.frame_cache[self.thumbnail_data["frame_time"]]["frame"],
+                self.frame_cache[frame_time]["frame"],
                 cv2.COLOR_YUV2BGR_I420,
             )
         except KeyError:
             logger.warning(
-                f"Unable to create jpg because frame {self.thumbnail_data['frame_time']} is not in the cache"
+                f"Unable to create jpg because frame {frame_time} is not in the cache"
             )
-            return None
+            return None, None
 
         if bounding_box:
             thickness = 2
@@ -570,13 +571,13 @@ class TrackedObject:
         ret, jpg = cv2.imencode(f".{ext}", best_frame, quality_params)
 
         if ret:
-            return jpg.tobytes()
+            return jpg.tobytes(), frame_time
         else:
-            return None
+            return None, None
 
     def write_snapshot_to_disk(self) -> None:
         snapshot_config: SnapshotsConfig = self.camera_config.snapshots
-        jpg_bytes = self.get_img_bytes(
+        jpg_bytes, _ = self.get_img_bytes(
             ext="jpg",
             timestamp=snapshot_config.timestamp,
             bounding_box=snapshot_config.bounding_box,