void
DurationIndex::Add(REFERENCE_TIME tStart, REFERENCE_TIME tEnd)
{
// In general it is safer to just use the start time of each sample
// since the stop time will be either wrong, or will just be deduced from
// the next sample start time.
// However, when frame re-ordering is happening, the composition time (== PTS) will
// not be the same as the decode time (== DTS) and we need to use both start and
// stop time to build the CTTS table.
// We save the first few timestamps and then decide which mode to be in.
if (m_nSamples < mode_decide_count)
{
if (m_nSamples == 0)
{
m_SumDurations = 0;
}
m_SumDurations += (tEnd - tStart);
m_SampleStarts[m_nSamples] = tStart;
m_SampleStops[m_nSamples] = tEnd;
m_nSamples++;
return;
}
else if (m_nSamples == mode_decide_count)
{
// this decides on a mode and then processes
// all the samples in the table
ModeDecide();
}
if (m_bCTTS)
{
AppendCTTSMode(tStart, tEnd);
}
else
{
AddDuration(long(ToScale(tStart) - m_TotalDuration));
}
m_nSamples++;
m_tStartLast = tStart;
m_tStopLast = tEnd;
return;
}
HRESULT
DurationIndex::WriteTable(Atom* patm)
{
// do nothing if no samples at all
HRESULT hr = S_OK;
if (m_nSamples <= mode_decide_count)
{
ModeDecide();
}
if (m_nSamples > 0)
{
if (!m_bCTTS)
{
// the final sample duration has not been recorded -- use the
// stop time
if (ToScale(m_tStopLast) > m_TotalDuration)
{
AddDuration(long(ToScale(m_tStopLast) - m_TotalDuration));
} else
// NOTE: We still need some duration recorded, to avoid stts/stsz discrepancy at the very least
AddDuration(1);
}
// create atom and write table
smart_ptr<Atom> pstts = patm->CreateAtom('stts');
m_STTS.Write(pstts);
pstts->Close();
if (m_bCTTS)
{
// write CTTS table
smart_ptr<Atom> pctts = patm->CreateAtom('ctts');
m_CTTS.Write(pctts);
pctts->Close();
}
}
return hr;
}