Depth estimation block in video inference workflow causing issues?

[floatr]

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• I have searched the Inference issues and found no similar bug report.

Bug

It seems like we're encountering a serialization issue with a video inference pipeline on a workflow including the depth estimation block.

The log trace indicates an issue in webrtc.py in the inference library.

{"event": "[DATA_ONLY] Error at frame 1: Unable to serialize unknown type: <class 'numpy.ndarray'>", "timestamp": "2026-03-23 15:37.15", "filename": "webrtc.py", "func_name": "process_frames_data_only", "lineno": 570}

{"event": "AssertionError: this is a bug! please report it", "request_id": "6ce713026cd74040a282ff65ec0aecff", "timestamp": "2026-03-23 15:50.39", "exception": {"type": "AssertionError", "message": "this is a bug! please report it", "stacktrace": [{"filename": "/app/inference/core/interfaces/http/error_handlers.py", "lineno": 101, "function": "wrapped_route", "code": "return route(*args, **kwargs)"}, {"filename": "/app/inference/core/interfaces/http/http_api.py", "lineno": 1670, "function": "describe_workflows_blocks", "code": "result = handle_describe_workflows_blocks_request("}, {"filename": "/app/inference/core/interfaces/http/handlers/workflows.py", "lineno": 86, "function": "handle_describe_workflows_blocks_request", "code": "uql_operations_descriptions = prepare_operations_descriptions()"}, {"filename": "/app/inference/core/workflows/core_steps/common/query_language/introspection/core.py", "lineno": 64, "function": "prepare_operations_descriptions", "code": "operations_chain_schema = OperationsChain.model_json_schema()"}, {"filename": "/usr/local/lib/python3.10/dist-packages/pydantic/main.py", "lineno": 555, "function": "model_json_schema", "code": "return model_json_schema("}, {"filename": "/usr/local/lib/python3.10/dist-packages/pydantic/json_schema.py", "lineno": 2412, "function": "model_json_schema", "code": "assert not isinstance(cls.pydantic_core_schema, _mock_val_ser.MockCoreSchema), 'this is a bug! please report it'"}]}, "filename": "error_handlers.py", "func_name": "wrapped_route", "lineno": 476}

Environment

No response

Minimal Reproducible Example

Run local video inference with gpu with a depth estimation block using depth anything v3/ small

Additional

No response

Are you willing to submit a PR?

• Yes I'd like to help by submitting a PR!

[PawelPeczek-Roboflow]

Hi there - I believe we identified the root cause - lack of serializer for NUMPY_ARRAY_KIND - should be possible to fix before next release.

[PawelPeczek-Roboflow]

@floatr - is the problem resolved?

[floatr]

Yes, it seems like it's resolved now. Thanks @PawelPeczek-Roboflow