IAMMediaStream::Initialize method (amstream.h)

Artikel
4/26/2023

[The feature associated with this page, DirectShow, is a legacy feature. It has been superseded by MediaPlayer, IMFMediaEngine, and Audio/Video Capture in Media Foundation. Those features have been optimized for Windows 10 and Windows 11. Microsoft strongly recommends that new code use MediaPlayer, IMFMediaEngine and Audio/Video Capture in Media Foundation instead of DirectShow, when possible. Microsoft suggests that existing code that uses the legacy APIs be rewritten to use the new APIs if possible.]

Note This interface is deprecated. New applications should not use it.

The Initialize method creates and initializes a new media stream with the specified stream type and purpose ID.

Syntax

HRESULT Initialize(
  [in] IUnknown          *pSourceObject,
  [in] DWORD             dwFlags,
  [in] REFMSPID          PurposeId,
  [in] const STREAM_TYPE StreamType
);

Parameters

[in] pSourceObject

Pointer to an IUnknown source object.

[in] dwFlags

Value that modifies the media stream's behavior; it is a combination of one or more of the following values.

Value	Description
AMMSF_ADDDEFAULTRENDERER	Add a default renderer.
AMMSF_CREATEPEER	Create a peer stream based on the same object as a pStreamObject.
AMMSF_NOSTALL	Run the stream even if Update is not called.
AMMSF_STOPIFNOSAMPLES	Terminates the stream if no samples were created or if the last sample is deleted.

[in] PurposeId

Purpose ID for the new media stream.

[in] StreamType

STREAM_TYPE enumeration value that specifies the new media stream's media type.

Return value

Returns S_OK if successful or E_POINTER if one or more of the required parameters are invalid.

Remarks

If dwFlags specifies AMMSF_ADDDEFAULTRENDERER, then the default renderer for the given purpose ID is created, if possible. Currently, the only default renderer supported is for audio using DirectSound. In this case, the pStreamObject parameter must be NULL and any calls to the IMultiMediaStream::GetMediaStream or IMultiMediaStream::EnumMediaStreams method will not recognize the stream.

If dwFlags specifies AMMSF_CREATEPEER, then a media stream is created using pStreamObject and added to the current multimedia stream. The pStreamObject parameter varies depending on the stream type. In general, pStreamObject can point to an IMediaStream object, in which case a stream with the sample purpose ID and format is created. For IDirectDraw streams, it can also be a pointer to an IDirectDraw interface.

If dwFlags specifies AMMSF_STOPIFNOSAMPLES, then the stream is terminated.

If no flags are set, then pStreamObject can be one of the following.

Value	Description
An IAMMediaStream object	This stream is then added to the streams in the multimedia stream.
NULL	In this case a default IMediaStream object is added to the stream with a default underlying object, if required.
A pointer to an underlying object	This is used to construct default streams. For video streams, this can be an IDirectDraw pointer.

Requirements

Requirement	Value
Target Platform	Windows
Header	amstream.h

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