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DMOEnum

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Microsoft DirectShow 9.0

DMOEnum

The DMOEnum function enumerates DMOs listed in the registry. The caller can search by category, media type, or both.

Syntax

  HRESULT DMOEnum(
    REFGUID guidCategory,
    DWORD dwFlags,
    DWORD cInTypes,
    const DMO_PARTIAL_MEDIATYPE *pInTypes,
    DWORD cOutTypes,
    const DMO_PARTIAL_MEDIATYPE *pOutTypes,
    IEnumDMO **ppEnum
);

Parameters

guidCategory

GUID that specifies which category of DMO to search. Use GUID_NULL to search every category. See DMO GUIDs for a list of category GUIDs.

dwFlags

Bitwise combination of zero or more flags from the DMO_ENUM_FLAGS enumeration.

cInTypes

Number of input media types to use in the search criteria. Use zero to match any input type.

pInTypes

Pointer to an array of DMO_PARTIAL_MEDIATYPE structures that contain the input media types. Specify the size of the array in the cInTypes parameter.

cOutTypes

Number of output media types to use in the search criteria. Use zero to match any output type.

pOutTypes

Pointer to an array of DMO_PARTIAL_MEDIATYPE structures that contain the output media types. Specify the size of the array in the cOutTypes parameter.

ppEnum

Address of a variable to receive the IEnumDMO interface of the enumerator.

Return Value

Returns an HRESULT value. Possible values include the following.

Result Code Description
E_FAIL Failure
E_OUTOFMEMORY Insufficient memory
S_OK Success

Remarks

This method returns a pointer to an enumerator object that supports the IEnumDMO interface. The application uses the IEnumDMO interface to enumerate over the set of DMOs that match the search criteria.

Requirements

  Header: Declared in Dmoreg.h; include Dmo.h
  Library: Msdmo.lib.

Example Code

The following example enumerates all audio effect DMOs on the user's system, including keyed DMOs.

IEnumDMO* pEnum = NULL; 
HRESULT hr = DMOEnum(
    DMOCATEGORY_AUDIO_EFFECT, // Category
    DMO_ENUMF_INCLUDE_KEYED,  // Included keyed DMOs
    0, NULL,                  // Input types (don't care)
    0, NULL,                  // Output types (don't care)
    &pEnum);

if (SUCCEEDED(hr)) 
{
    CLSID clsidDMO;
    WCHAR* wszName;
    do
    {
        hr = pEnum->Next(1, &clsidDMO, &wszName, NULL);
        if (hr == S_OK) 
        {  
            // Now wszName holds the friendly name of the DMO, 
            // and clsidDMO holds the CLSID. 

            // Remember to release wszName!
            CoTaskMemFree(wszName);
        }
    } while (hr == S_OK);
    pEnum->Release();
}

See Also