Error 0x80040294

Value: -2147220844 | 0x80040294 | 2147746452

What does it mean ?

VFW_E_PIN_ALREADY_BLOCKED  
IPinFlowControl::Block() has been called on another thread. The current thread cannot make any assumptions about this pin's block state.%0
Value: 660 | 0x0294 | 0b0000001010010100

Where does it come from ?

FACILITY_ITF  
COM/OLE Interface management. FACILITY_ITF is designated for user-defined error codes returned from interface methods
Value: 4 | 0x004 | 0b00000100

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Other Errors for FACILITY_ITF