// Called when the presentation clock restarts from the same position while paused.
HRESULT STDMETHODCALLTYPE EVRCustomPresenter::OnClockRestart(MFTIME hnsSystemTime)
{
Log("EVRCustomPresenter::OnClockRestart");
HRESULT hr = S_OK;
CAutoLock lock(this);
// We cannot restart the clock after shutdown.
hr = CheckShutdown();
CHECK_HR(hr, "EVRCustomPresenter::OnClockRestart cannot restart after shutdown");
// The EVR calls OnClockRestart only while paused.
assert(m_RenderState == RENDER_STATE_PAUSED);
m_RenderState = RENDER_STATE_STARTED;
// Possibly we are in the middle of frame-stepping OR we have samples waiting in the frame-step queue.
hr = StartFrameStep();
CHECK_HR(hr, "EVRCustomPresenter::OnClockRestart EVRCustomPresenter::StartFrameStep() failed")
// Now resume the presentation loop.
ProcessOutputLoop();
return hr;
}
// Gets ready to frame step.
HRESULT EVRCustomPresenter::PrepareFrameStep(DWORD cSteps)
{
HRESULT hr = S_OK;
// Cache the step count.
m_FrameStep.steps += cSteps;
// Set the frame-step state.
m_FrameStep.state = FRAMESTEP_WAITING_START;
// If the clock is are already running, we can start frame-stepping now. Otherwise, we will start when the clock starts.
if (m_RenderState == RENDER_STATE_STARTED)
{
hr = StartFrameStep();
}
return hr;
}
// Called when the presentation clock starts.
HRESULT STDMETHODCALLTYPE EVRCustomPresenter::OnClockStart(MFTIME hnsSystemTime, LONGLONG llClockStartOffset)
{
Log("EVRCustomPresenter::OnClockStart (offset = %I64d)", llClockStartOffset);
HRESULT hr = S_OK;
CAutoLock lock(this);
// We cannot start after shutdown
hr = CheckShutdown();
CHECK_HR(hr, "EVRCustomPresenter::OnClockRestart cannot start after shutdown");
// Check if the clock is already active (not stopped).
if (IsActive())
{
m_RenderState = RENDER_STATE_STARTED;
// If the clock position changes while the clock is active, it is a seek request. We need to flush all pending samples.
if (llClockStartOffset != PRESENTATION_CURRENT_POSITION)
{
Flush();
}
}
else
{
// The clock has started from the stopped state.
m_RenderState = RENDER_STATE_STARTED;
// Possibly we are in the middle of frame-stepping or have samples waiting in the frame-step queue.
hr = StartFrameStep();
CHECK_HR(hr, "EVRCustomPresenter::OnClockRestart EVRCustomPresenter::StartFrameStep() failed");
}
// Now try to get new output samples from the mixer.
ProcessOutputLoop();
return hr;
}
