IAMBufferNegotiation::SuggestAllocatorProperties (Compact 2013)
3/26/2014
This method informs the pin of the application's preferred allocator properties. Call this method before the pin connects.
Syntax
HRESULT SuggestAllocatorProperties(
const ALLOCATOR_PROPERTIES* pprop
);
Parameters
- pprop
[in] Pointer to an ALLOCATOR_PROPERTIES structure that contains the requested properties. A negative value for any member indicates that the pin should use its default setting for that property.
Return Value
Returns an HRESULT value. The following table shows some of the possible return values.
Value |
Description |
|---|---|
S_OK |
Success. |
E_FAIL |
Failure. |
E_POINTER |
NULL pointer argument. |
VFW_E_ALREADY_CONNECTED |
Pin is already connected. |
Remarks
If both pins in the connection expose the IAMBufferNegotiation interface, call this method on each pin, to ensure that one pin does not override the other.
To request a particular number of buffers, set the cBuffers member of the ALLOCATOR_PROPERTIES structure. To request a particular buffer size, set the cbBuffer member. An application typically should not specify the alignment or prefix. If the number of buffers or size of each buffer is too small, the filter graph might drop samples.
The following code example shows how to call this method.
ALLOCATOR_PROPERTIES AllocProp;
AllocProp.cbAlign = -1; // -1 means no preference.
AllocProp.cbBuffer = dwBytesPerSec * dwLatencyInMilliseconds / 1000;
AllocProp.cbPrefix = -1;
AllocProp.cBuffers = -1;
pIAMBufferNegotiation->SuggestAllocatorProperties(&AllocProp);
Requirements
Header |
dshow.h |
Library |
Strmiids.lib |