When is it safe to release IMFSample and data?

Question

According to the tutorial here: http://msdn.microsoft.com/en-us/library/windows/desktop/ff819477(v=vs.85).aspx, it looks like we are supposed to release the sample and sample buffer right away:
// Send the sample to the Sink Writer.
if (SUCCEEDED(hr))
hr = pWriter->WriteSample(streamIndex, pSample);
SafeRelease(&pSample);
SafeRelease(&pBuffer);
But sometimes I get heap corruption errors when doing this.. if I omit the calls to SafeRelease the sample and buffer, I leak memory, but I don't get heap corruption errors.  From what I understand, the IMFSinkWriter queues up the samples sent to it and
writes them in its own good time.. so, it does make sense that heap corruption happens when I release the sample before the sink writer gets a chance to write it.  Is this what is happening?  If so, how should I clean up the memory responsibly?  Do
I need to put an asynchronous call back on the sink writer and use that to monitor when samples are finished so I can delete the memory?  That seems cumbersome, and I've never seen that done in any microsoft examples, so I'm sort of wondering what to
do.

Answer 1

For posterity, here is the answer, answered on stack overflow:
http://stackoverflow.com/questions/27861080/when-is-it-safe-to-release-an-imfsample-and-its-data/27862288#27862288
No, it's not necessary to put on an asynchronous callback to free the memory.