protected int ProcessOutput()
{
Debug.Assert(m_bSampleNotify || m_bRepaint); // See note above.
int hr = S_Ok;
ProcessOutputStatus dwStatus = 0;
long mixerStartTime = 0, mixerEndTime = 0;
long systemTime = 0;
bool bRepaint = m_bRepaint; // Temporarily store this state flag.
MFTOutputDataBuffer[] dataBuffer = new MFTOutputDataBuffer[1];
IMFSample pSample = null;
// If the clock is not running, we present the first sample,
// and then don't present any more until the clock starts.
if ((m_RenderState != RenderState.Started) && // Not running.
!m_bRepaint && // Not a repaint request.
m_bPrerolled // At least one sample has been presented.
)
{
return S_False;
}
// Make sure we have a pointer to the mixer.
if (m_pMixer == null)
{
return MFError.MF_E_INVALIDREQUEST;
}
if (!m_bRepaint)
{
MFTOutputStatusFlags osf;
hr = m_pMixer.GetOutputStatus(out osf);
MFError.ThrowExceptionForHR(hr);
if ((osf & MFTOutputStatusFlags.SampleReady) == 0)
{
m_bSampleNotify = false;
return S_Ok;
}
}
try
{
// Try to get a free sample from the video sample pool.
m_SamplePool.GetSample(out pSample);
if (pSample == null)
{
return S_False; // No free samples. We'll try again when a sample is released.
}
// (If the following assertion fires, it means we are not managing the sample pool correctly.)
//Debug.Assert(MFGetAttributeUINT32(pSample, MFSamplePresenter_SampleCounter, -1) == m_TokenCounter);
if (m_bRepaint)
{
// Repaint request. Ask the mixer for the most recent sample.
SetDesiredSampleTime(pSample, m_scheduler.LastSampleTime(), m_scheduler.FrameDuration());
m_bRepaint = false; // OK to clear this flag now.
}
else
{
// Not a repaint request. Clear the desired sample time; the mixer will
// give us the next frame in the stream.
ClearDesiredSampleTime(pSample);
if (m_pClock != null)
{
// Latency: Record the starting time for the ProcessOutput operation.
hr = m_pClock.GetCorrelatedTime(0, out mixerStartTime, out systemTime);
MFError.ThrowExceptionForHR(hr);
}
}
// Now we are ready to get an output sample from the mixer.
dataBuffer[0].dwStreamID = 0;
dataBuffer[0].dwStatus = 0;
dataBuffer[0].pEvents = null;
dataBuffer[0].pSample = Marshal.GetIUnknownForObject(pSample);
try
{
hr = m_pMixer.ProcessOutput(0, 1, dataBuffer, out dwStatus);
MFError.ThrowExceptionForHR(hr);
// Release any events that were returned from the ProcessOutput method.
// (We don't expect any events from the mixer, but this is a good practice.)
ReleaseEventCollection(dataBuffer.Length, dataBuffer);
}
catch (Exception e)
{
hr = Marshal.GetHRForException(e);
}
finally
{
Marshal.Release(dataBuffer[0].pSample);
//SafeRelease(dataBuffer[0].pSample);
}
if (Failed(hr))
{
// Return the sample to the pool.
m_SamplePool.ReturnSample(pSample);
// Handle some known error codes from ProcessOutput.
if (hr == MFError.MF_E_TRANSFORM_TYPE_NOT_SET)
{
// The mixer's format is not set. Negotiate a new format.
RenegotiateMediaType();
}
else if (hr == MFError.MF_E_TRANSFORM_STREAM_CHANGE)
{
// There was a dynamic media type change. Clear our media type.
SetMediaType(null);
}
else if (hr == MFError.MF_E_TRANSFORM_NEED_MORE_INPUT)
{
// The mixer needs more input.
// We have to wait for the mixer to get more input.
m_bSampleNotify = false;
}
else
{
MFError.ThrowExceptionForHR(hr);
}
}
else
{
// We got an output sample from the mixer.
if (m_pClock != null && !bRepaint)
{
// Latency: Record the ending time for the ProcessOutput operation,
// and notify the EVR of the latency.
hr = m_pClock.GetCorrelatedTime(0, out mixerEndTime, out systemTime);
MFError.ThrowExceptionForHR(hr);
long latencyTime = mixerEndTime - mixerStartTime;
GCHandle gh = GCHandle.Alloc(latencyTime, GCHandleType.Pinned);
try
{
// This event (EventCode.ProcessingLatency) isn't defined until DirectShowNet v2.1
NotifyEvent((EventCode)0x21, gh.AddrOfPinnedObject(), IntPtr.Zero);
}
finally
{
gh.Free();
}
}
// Set up notification for when the sample is released.
TrackSample(pSample);
// Schedule the sample.
if ((m_FrameStep.state == FrameStepRate.None) || bRepaint)
{
DeliverSample(pSample, bRepaint);
}
else
{
// We are frame-stepping (and this is not a repaint request).
DeliverFrameStepSample(pSample);
}
m_bPrerolled = true; // We have presented at least one sample now.
}
}
finally
{
//SafeRelease(pSample);
}
return S_Ok;
}
protected void ReleaseEventCollection(int cOutputBuffers, MFTOutputDataBuffer[] pBuffers)
{
for (int i = 0; i < cOutputBuffers; i++)
{
SafeRelease(pBuffers[i].pEvents);
pBuffers[i].pEvents = null;
}
}
/// <summary> /// The routine that usually performs the transform. /// </summary> /// <param name="pOutputSamples">The structure to populate with output values.</param> /// <returns>S_Ok unless error.</returns> /// <remarks> /// The input sample is in InputSample. Process it into the pOutputSamples struct. /// Depending on what you set in On*StreamInfo, you can either perform /// in-place processing by modifying the input sample (which still must /// set inout the struct), or create a new IMFSample and FULLY populate /// it from the input. If the input sample has been fully processed, /// set InputSample to null. /// </remarks> abstract protected HResult OnProcessOutput(ref MFTOutputDataBuffer pOutputSamples);
