|Microsoft DirectX 9.0|
The AllocateStreamingResources method allocates any resources needed by the DMO. Calling this method is always optional.
Returns S_OK if successful. Otherwise, returns an HRESULT value indicating the cause of the error.
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 supports this method, it should also support the IMediaObject::FreeStreamingResources method.