CPullPin.DecideAllocator method
[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 It has been superseded by MediaPlayer, IMFMediaEngine, and Audio/Video Capture in Media Foundation.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 DecideAllocator method negotiates an allocator with the output pin.
Syntax
virtual HRESULT DecideAllocator(
IMemAllocator *pAlloc,
ALLOCATOR_PROPERTIES *pProps
);
Parameters
-
pAlloc
-
Pointer to the IMemAllocator interface of the input pin's preferred allocator, or NULL.
-
pProps
-
Pointer to an optional ALLOCATOR_PROPERTIES structure that contains the input pin's buffer requirements.
Return value
Returns S_OK if successful, or an error code otherwise.
Remarks
This method calls the IAsyncReader::RequestAllocator method to negotiate an allocator. It passes the pAlloc parameter directly to the RequestAllocator method. It passes the pProps parameter to RequestAllocator if pProps is non-NULL; otherwise, it creates an ALLOCATOR_PROPERTIES structure with a default request of three 64K buffers.
Requirements
| Requirement | Value |
|---|---|
| Header |
|
| Library |
|