IWMReaderAdvanced2::OpenStream method (wmsdkidl.h)

项目
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 It has been superseded by Source Reader and Sink Writer.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 OpenStream method opens a Windows Media stream for reading.

Syntax

HRESULT OpenStream(
  [in] IStream           *pStream,
  [in] IWMReaderCallback *pCallback,
  [in] void              *pvContext
);

Parameters

[in] pStream

Pointer to an IStream interface (see the Remarks section below).

[in] pCallback

Pointer to an IWMReaderCallback interface.

[in] pvContext

Generic pointer, for use by the application. This is passed to the application in calls to IWMReaderCallback::OnStatus.

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_POINTER	The pCallback parameter is NULL.
E_OUTOFMEMORY	There is not enough available memory.
E_UNEXPECTED	The method failed for an unspecified reason.

Remarks

This method is identical to IWMReader::Open, except that it takes an IStream interface pointer instead of a URL. An IStream is a standard COM interface for providing data. This allows the application to provide its own data, rather than just getting data from a file or a network. For example, if you have an IStream interface pointer that represents the contents of a supported media file (Windows Media Audio, Windows Media Video, MP3, for example) and, for performance reasons, you do not want to write a temporary file , this is a way you can use the SDK to parse and decompress your content.

This method sends a WMT_OPENED status notification to the application's IWMReaderCallback::OnStatus function. (OnStatus is inherited by IWMReaderCallback from IWMStatusCallback.)

Requirements

Requirement	Value
Minimum supported client	Windows 2000 Professional [desktop apps only],Windows Media Format 7 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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