| Microsoft DirectX 8.1 (C++) | 
The QueryOperationModePreferences method retrieves the DMO's preferred optimization features.
Syntax
HRESULT QueryOperationModePreferences(
    ULONG ulOutputStreamIndex,
    DWORD* pdwRequestedCapabilities
);
Parameters
ulOutputStreamIndex
Zero-based index of an output stream on the DMO.
pdwRequestedCapabilities
Pointer to a variable that receives the DMO's requested features. The returned value is a bitwise combination of zero or more flags from the DMO_VIDEO_OUTPUT_STREAM_FLAGS enumeration.
Return Value
Returns an HRESULT value. Possible values include those in the following table.
| Return Code | Description | 
| DMO_E_INVALIDSTREAMINDEX | Invalid stream index | 
| E_POINTER | NULL pointer argument | 
| S_OK | Success | 
See Also