IWMStreamConfig2::AddDataUnitExtension method (wmsdkidl.h)

Artigo
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 It has been superseded by Source Reader and Sink Writer.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 AddDataUnitExtension method adds a data unit extension system to the stream. You can use data unit extension systems to attach custom data to samples in an output file.

Syntax

HRESULT AddDataUnitExtension(
  [in] GUID  guidExtensionSystemID,
  [in] WORD  cbExtensionDataSize,
  [in] BYTE  *pbExtensionSystemInfo,
  [in] DWORD cbExtensionSystemInfo
);

Parameters

[in] guidExtensionSystemID

A GUID that identifies the data unit extension system. This can be one of the predefined GUIDs listed in INSSBuffer3::SetProperty, or a GUID whose value is understood by a custom player application.

[in] cbExtensionDataSize

Size, in bytes, of the data unit extensions that will be attached to the packets in the stream. Set to 0xFFFF to specify data unit extensions of variable size. Each individual data unit extension can then be set to any size ranging from 0 to 65534.

[in] pbExtensionSystemInfo

Pointer to a byte buffer containing information about the data unit extension system. If you have no information, you can pass NULL. When passing NULL, cbExtensionSystemInfo must be zero.

[in] cbExtensionSystemInfo

Count of bytes in the buffer at pbExtensionSystemInfo. If you have no data unit extension system information, you can pass zero. When passing zero, pbExtensionSystemInfo must be NULL.

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.
E_INVALIDARG	cbExtensionSystemInfo specifies a non-zero value, but pbExtensionSystemInfo is NULL.
E_OUTOFMEMORY	The method cannot allocate memory to hold the new data unit extension.

Remarks

Passing the GUID of an existing data unit extension system does not cause an error. The old system is destroyed and replaced by the new one.

The new value will not take effect in the profile until you call IWMProfile::ReconfigStream.

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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