What does HRESULT 0x0004022D (VFW_S_DUPLICATE_NAME) mean?

VFW_S_DUPLICATE_NAME

DirectShow filter added with an adjusted duplicate name

VFW_S_DUPLICATE_NAME is HRESULT 262701 (0x0004022D) from Video for Windows. The documented description is “An attempt to add a filter with a duplicate name succeeded with a modified name.” The high-order severity bit is clear, so this is a success result, but it carries more information than plain S_OK.

The filter was added successfully, but the graph changed its display name because the requested name duplicated an existing filter name.

Where the result is encountered

• This result can appear in IFilterGraph::AddFilter; record the producing interface and method.
• This result can appear in graph-building tools that address filters by friendly name; record the producing interface and method.
• It can appear in applications loading multiple instances of the same filter; record the producing interface and method.

State to verify

The central question is whether the filter identity is tracked by its interface pointer or graph membership rather than by the originally requested name alone.

Evidence to preserve

• Preserve requested and actual filter names.
• Preserve filter CLSID and interface pointer.
• Preserve graph filter list before and after addition.
• Preserve application lookup strategy.
• Preserve saved graph representation if persisted.

Correct handling, retry, and recovery

Use the actual assigned name or, preferably, retain the filter interface directly. Avoid assuming that a friendly name is globally unique inside a graph.

Diagnostic sequence

• Capture the raw HRESULT 0x0004022D immediately after the returning method and record whether the caller used SUCCEEDED, FAILED, equality testing, or exception translation.
• Verify the method-specific state: the filter identity is tracked by its interface pointer or graph membership rather than by the originally requested name alone.

Practical validation scenario

An application adds two decoder instances both named Decoder. The second call returns it and assigns a modified name; the application stores each IBaseFilter pointer and displays the actual graph names.

Difference from nearby HRESULT values

S_OK means the requested name was accepted without this adjustment; VFW_E_DUPLICATE_NAME-style failures would not add the filter.

Developer and administrator guidance

References

• Microsoft: DirectShow error and success codes
• Microsoft: DirectShow overview
• Microsoft: IFilterGraph::AddFilter