IWMCodecInfo3::SetCodecEnumerationSetting method (wmsdkidl.h)

Статья
4/26/2023

[The feature associated with this page, Windows Media Format 11 SDK, is a legacy feature. It has been superseded by Source Reader and Sink Writer. Source Reader and Sink Writer have been optimized for Windows 10 and Windows 11. Microsoft strongly recommends that new code use Source Reader and Sink Writer instead of Windows Media Format 11 SDK, when possible. Microsoft suggests that existing code that uses the legacy APIs be rewritten to use the new APIs if possible.]

The SetCodecEnumerationSetting method sets the value of one codec enumeration setting. Codec enumeration settings dictate the codec formats that can be enumerated by the methods of IWMCodecInfo.

Syntax

HRESULT SetCodecEnumerationSetting(
  [in] REFGUID           guidType,
  [in] DWORD             dwCodecIndex,
  [in] LPCWSTR           pszName,
  [in] WMT_ATTR_DATATYPE Type,
  [in] const BYTE        *pValue,
  [in] DWORD             dwSize
);

Parameters

[in] guidType

GUID identifying the major type of digital media. This must be one of the following constants.

Constant	Description
WMMEDIATYPE_Video	Specifies a video codec.
WMMEDIATYPE_Audio	Specifies an audio codec.

[in] dwCodecIndex

DWORD containing the codec index ranging from zero to one less than the number of supported codecs of the type specified by guidType. To retrieve the number of individual codecs supporting a major type, use the IWMCodecInfo::GetCodecInfoCount method.

[in] pszName

Pointer to a wide-character null-terminated string containing the name of the enumeration setting. Use one of the following constants.

Constant	Description
g_wszVBREnabled	Use to enumerate the supported codec formats that use variable bit rate (VBR) encoding.The value returned in pValue is a BOOL.
g_wszNumPasses	Use to enumerate the supported codec formats that use a number of passes equal to the value in pValue.The value returned in pValue is a DWORD specifying the number of passes.

[in] Type

A WMT_ATTR_DATATYPE value specifying the data type of the value in pValue.

[in] pValue

A pointer to a BYTE array containing the setting value.

[in] dwSize

DWORD containing the size of the pValue BYTE array.

Return value

The method returns an HRESULT. Possible values include, but are not limited to, those in the following table.

Return code	Description
S_OK	The method succeeded; the feature is supported by the codec.
NS_E_UNSUPPORTED_PROPERTY	The enumeration setting specified is not valid for the codec.

Remarks

The Windows Media Audio and Video 9 Series codecs can potentially enumerate four different sets of codec formats, as listed in the following table.

	Constant bit rate (CBR) stream	Two-pass CBR stream	Quality-based variable bit rate (VBR) stream	Bit-rate-based VBR stream (constrained or unconstrained)
g_wszVBREnabled	FALSE	FALSE	TRUE	TRUE
g_wszNumPasses	1	2	1	2

Not all codecs support all formats.

If you make a call to this method and get the NS_E_UNSUPPORTED_PROPERTY error code, then the codec does not support that feature. For example, if an attempt to set g_wszNumPasses returns NS_E_UNSUPPORTED_PROPERTY, the codec does not support multiple encoding passes.

The return value of a call made to this method does not guarantee support of a codec feature. For example, the Windows Media Audio 9 Lossless codec does not return NS_E_UNSUPPORTED_PROPERTY for calls that set the number of passes, even though the codec does not support two-pass encoding.

Requirements

Requirement	Value
Minimum supported client	Windows 2000 Professional [desktop apps only],Windows Media Format 9 Series SDK, or later versions of the SDK
Minimum supported server	Windows 2000 Server [desktop apps only]
Target Platform	Windows
Header	wmsdkidl.h (include Wmsdk.h)
Library	Wmvcore.lib; WMStubDRM.lib (if you use DRM)

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