diff --git a/src/services/generation_handler.py b/src/services/generation_handler.py
index 28ee00d0..118dd722 100644
--- a/src/services/generation_handler.py
+++ b/src/services/generation_handler.py
@@ -1438,12 +1438,14 @@ async def _resolve_video_asset(
             str(operation.get("projectId") or video_info.get("projectId") or "").strip()
             or None
         )
+        # as29s indexes by generation operation id, not mediaName; the two are
+        # distinct UUIDs and the wrong one comes back as code=[5] (NOT_FOUND).
         media_name = (
-            operation.get("mediaName")
-            or video_info.get("mediaName")
-            or video_info.get("mediaGenerationId")
+            video_info.get("mediaGenerationId")
             or operation.get("name")
             or (operation.get("operation") or {}).get("name")
+            or operation.get("mediaName")
+            or video_info.get("mediaName")
         )
 
         video_url = ""
diff --git a/tests/test_video_asset_resolution.py b/tests/test_video_asset_resolution.py
new file mode 100644
index 00000000..b590a560
--- /dev/null
+++ b/tests/test_video_asset_resolution.py
@@ -0,0 +1,61 @@
+import unittest
+from unittest.mock import AsyncMock, MagicMock
+
+from src.services.generation_handler import GenerationHandler
+
+
+MEDIA_NAME = "4a7b00b4-a60f-44d2-a5fa-c0a4883c5fcc"
+GENERATION_ID = "a1607a19-a932-4c31-bb39-b5f6283f1eee"
+VIDEO_URL = f"https://flow-content.google/video/{GENERATION_ID}"
+
+
+def _operation():
+    return {
+        "status": "MEDIA_GENERATION_STATUS_SUCCESSFUL",
+        "projectId": "86955db9-5925-4e7b-b7ed-a3e9c5302c92",
+        "mediaName": MEDIA_NAME,
+        "name": GENERATION_ID,
+        "operation": {
+            "name": GENERATION_ID,
+            "metadata": {
+                "video": {
+                    "mediaName": MEDIA_NAME,
+                    "mediaGenerationId": GENERATION_ID,
+                    "aspectRatio": "VIDEO_ASPECT_RATIO_LANDSCAPE",
+                }
+            },
+        },
+    }
+
+
+class VideoAssetResolutionTests(unittest.IsolatedAsyncioTestCase):
+    def setUp(self):
+        self.handler = GenerationHandler.__new__(GenerationHandler)
+        self.handler.flow_client = MagicMock()
+        self.handler.flow_client.get_media_url_redirect = AsyncMock(return_value=VIDEO_URL)
+
+    async def test_resolves_media_by_generation_id_not_media_name(self):
+        """as29s 按生成操作 id 索引；传 mediaName 会返回 code=[5]。"""
+        resolved = await self.handler._resolve_video_asset(MagicMock(), _operation())
+
+        self.handler.flow_client.get_media_url_redirect.assert_awaited_once()
+        _, passed_id = self.handler.flow_client.get_media_url_redirect.await_args.args
+        self.assertEqual(passed_id, GENERATION_ID)
+        self.assertNotEqual(passed_id, MEDIA_NAME)
+        self.assertEqual(resolved["video_url"], VIDEO_URL)
+        self.assertEqual(resolved["video_media_id"], GENERATION_ID)
+
+    async def test_falls_back_to_operation_name_when_metadata_missing(self):
+        operation = _operation()
+        operation["operation"]["metadata"] = {}
+        operation.pop("name")
+
+        resolved = await self.handler._resolve_video_asset(MagicMock(), operation)
+
+        _, passed_id = self.handler.flow_client.get_media_url_redirect.await_args.args
+        self.assertEqual(passed_id, GENERATION_ID)
+        self.assertEqual(resolved["video_url"], VIDEO_URL)
+
+
+if __name__ == "__main__":
+    unittest.main()