IMemAllocator::GetBuffer

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Retrieves a container for a sample.

HRESULT GetBuffer( IMediaSample **
ppBuffer
,
REFERENCE_TIME *
pStartTime
,
REFERENCE_TIME *
pEndTime
,
DWORD
dwFlags
);

Parameters

ppBuffer

[out] Pointer to a retrieved media sample buffer.

pStartTime

[in] Either NULL or set to the beginning time of the sample to retrieve. Only the video renderer uses this.

pEndTime

[in] Either NULL or set to the ending time of the sample to retrieve. Only the video renderer uses this.

dwFlags

[in] GetBuffersupports the following flags.

AM_GBF_NOTASYNCPOINT

Dynamic format changes are not allowed on this buffer because it is not a key frame.

AM_GBF_PREVFRAMESKIPPED

Set to TRUE if this sample is the first after a discontinuity. Only the video renderer uses this.

Return Values

Returns an HRESULTvalue that depends on the implementation. HRESULTcan be one of the following standard constants, or other values not listed.

E_FAIL	Failure.
E_POINTER	Null pointer argument.
E_INVALIDARG	Invalid argument.
E_NOTIMPL	Method isn't supported.
S_OK or NOERROR	Success.

Remarks

IMemAllocator::GetBufferis a locking, synchronous method to get the next free buffer. Upon return, the properties are invalid, but the buffer pointer and size are correct. This method succeeds only if memory has been committed. GetBufferreturns with an error value if it is blocked waiting for a buffer, and the IMemAllocator::Decommitmethod is called on another thread.

If the pStartTimeand pEndTimeparameters are not NULL, they specify the intended start and end time for the sample in stream time (reference clock time minus the stream time offset). The video renderer applies these parameters when using DirectDraw to schedule when to return a sample. If pStartTimeand pEndTimeare NULL the video renderer will not use DirectDraw.