IMediaObject::AllocateStreamingResources method (mediaobj.h)

[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 It has been superseded by MediaPlayer, IMFMediaEngine, and Audio/Video Capture in Media Foundation.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.]

The AllocateStreamingResources method allocates any resources needed by the DMO. Calling this method is always optional.

Syntax

HRESULT AllocateStreamingResources();

Return value

Returns S_OK if successful. Otherwise, returns an HRESULT value indicating the cause of the error.

Remarks

An application can call this method as a streaming optimization. It gives the DMO an opportunity to perform any time-consuming initializations before streaming begins. If you call this method, do so after you set the media types on the DMO, but before you make the first calls to ProcessInput or ProcessOutput.

This method is optional in the following sense:

• If the DMO does not support this method, the method returns S_OK.
• If the application never calls this method, the DMO allocates resources within a call to IMediaObject::ProcessInput or IMediaObject::ProcessOutput.

Requirements

See also

IMediaObject Interface