fix(volcengine): unpack Ark parameters sent through extra_body

litellm/llms/volcengine/videos/transformation.py

@@ -592,8 +592,13 @@ class VolcEngineVideoConfig(BaseVideoConfig):
         and an omitted length is sent as OpenAI's documented default of 4 seconds, since the 2.5 family's own default
         is ``-1``.
         """
-        params: Final = video_create_optional_request_params
         drop_params: Final = _drops_params(litellm_params)
+        params: Final = MappingProxyType(
+            {
+                **{key: value for key, value in video_create_optional_request_params.items() if key != "parameters"},
+                **_parameters_fields(video_create_optional_request_params.get("parameters"), model, drop_params),
+            }
+        )
         content: Final = _sent_content(prompt, params, model, drop_params)
         if params.get("frames") is not None and not drop_params:
             raise _droppable(model, "frames is not supported through litellm, pass seconds instead")

tests/unit/llms/volcengine/test_volcengine_video_transformation.py

@@ -876,6 +876,24 @@ async def test_seconds_size_and_extra_body_content_reach_the_wire():
     }
 
 
+@pytest.mark.asyncio
+@pytest.mark.parametrize(
+    "fields",
+    [{"parameters": {"seed": 3}}, {"extra_body": {"parameters": {"seed": 3}}}],
+    ids=["top_level", "extra_body"],
+)
+async def test_parameters_reach_the_wire_unpacked_whether_sent_top_level_or_in_extra_body(fields: dict[str, object]):
+    body = await _wire_body(model=f"volcengine/{SEEDANCE_2_5}", prompt="p", seconds="4", **fields)
+
+    assert body == {
+        "model": SEEDANCE_2_5,
+        "content": [{"type": "text", "text": "p"}],
+        "resolution": "720p",
+        "duration": 4,
+        "seed": 3,
+    }
+
+
 @pytest.mark.asyncio
 async def test_an_extra_body_duration_of_minus_one_is_rejected_before_anything_is_sent():
     with pytest.raises(UnsupportedParamsError, match="Ark-picked length"):