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<blockquote data-quote="tourettes" data-source="post: 661206" data-attributes="member: 10858">Thanks! I think your proposal doesn't take into account the drifting of audio and system clocks (only works around the discontinuity points). I have taken a bit different approach - calculating the clock drifting based on the timestamps when those are available. here's the current implementation:[code]&nbsp; DWORD dwTime = timeGetTime();&nbsp; UINT64 hwClock(0);&nbsp; UINT64 hwQpc(0);&nbsp; HRESULT hr = m_pAudioRenderer-&gt;AudioClock(hwClock, hwQpc);&nbsp; if (hr == S_OK)&nbsp; {&nbsp; &nbsp; if (m_dStartQpcHW == 0)&nbsp; &nbsp; &nbsp; m_dStartQpcHW = hwQpc;&nbsp; &nbsp; if (m_dStartTimeHW == 0)&nbsp; &nbsp; &nbsp; m_dStartTimeHW = hwClock;&nbsp; &nbsp; if (m_dPrevTimeHW &gt; hwClock)&nbsp; &nbsp; {&nbsp; &nbsp; &nbsp; m_dStartTimeHW = m_dPrevTimeHW = hwClock;&nbsp; &nbsp; &nbsp; m_dStartQpcHW = m_dPrevQpcHW = hwQpc;&nbsp; &nbsp; }&nbsp; &nbsp; else&nbsp; &nbsp; {&nbsp; &nbsp; &nbsp; double clockDiff = hwClock - m_dStartTimeHW;&nbsp; &nbsp; &nbsp; double qpcDiff = hwQpc - m_dStartQpcHW;&nbsp; &nbsp; &nbsp; if (clockDiff &gt; 0 &amp;&amp; qpcDiff &gt; 0)&nbsp; &nbsp; &nbsp; &nbsp; m_dSystemClockMultiplier =&nbsp; clockDiff / qpcDiff;&nbsp; &nbsp; &nbsp; // TODO id this needed?&nbsp; &nbsp; &nbsp; if (m_dSystemClockMultiplier &lt; 0.95 || m_dSystemClockMultiplier &gt; 1.05)&nbsp; &nbsp; &nbsp; &nbsp; m_dSystemClockMultiplier = 1.0;&nbsp; &nbsp; &nbsp; m_dPrevTimeHW = hwClock;&nbsp; &nbsp; &nbsp; m_dPrevQpcHW = hwQpc;&nbsp; &nbsp; }&nbsp; }&nbsp; else&nbsp; {&nbsp; &nbsp; //Log(&quot;AudioClock() returned error (0x%08x)&quot;);&nbsp; }&nbsp; REFERENCE_TIME delta = REFERENCE_TIME(dwTime) - REFERENCE_TIME(m_dwPrevSystemTime);&nbsp; if(dwTime &lt; m_dwPrevSystemTime)&nbsp; {&nbsp; &nbsp; delta +=&nbsp; REFERENCE_TIME(UINT_MAX) + 1;&nbsp; }&nbsp; m_dwPrevSystemTime = dwTime;&nbsp; delta = (REFERENCE_TIME)(delta * (UNITS / MILLISECONDS) * m_dAdjustment * m_dBias);&nbsp; if (m_bHWBasedRefClock)&nbsp; &nbsp; delta *= m_dSystemClockMultiplier;&nbsp; //Log(&quot;mul: %.10f delta: %I64d - hwClock: %I64d hwQpc: %I64d qpc: %I64d clock diff: %I64d qpc diff: %I64d&quot;, m_dSystemClockMultiplier, delta, hwClock, hwQpc, qpcNow, hwClock - m_dStartTimeHW, hwQpc - m_dStartQpcHW);&nbsp; m_rtPrivateTime = m_rtPrivateTime + delta;&nbsp; return m_rtPrivateTime;[/code]</blockquote>

[QUOTE="tourettes, post: 661206, member: 10858"] Thanks! I think your proposal doesn't take into account the drifting of audio and system clocks (only works around the discontinuity points). I have taken a bit different approach - calculating the clock drifting based on the timestamps when those are available. here's the current implementation: [code] DWORD dwTime = timeGetTime(); UINT64 hwClock(0); UINT64 hwQpc(0); HRESULT hr = m_pAudioRenderer->AudioClock(hwClock, hwQpc); if (hr == S_OK) { if (m_dStartQpcHW == 0) m_dStartQpcHW = hwQpc; if (m_dStartTimeHW == 0) m_dStartTimeHW = hwClock; if (m_dPrevTimeHW > hwClock) { m_dStartTimeHW = m_dPrevTimeHW = hwClock; m_dStartQpcHW = m_dPrevQpcHW = hwQpc; } else { double clockDiff = hwClock - m_dStartTimeHW; double qpcDiff = hwQpc - m_dStartQpcHW; if (clockDiff > 0 && qpcDiff > 0) m_dSystemClockMultiplier = clockDiff / qpcDiff; // TODO id this needed? if (m_dSystemClockMultiplier < 0.95 || m_dSystemClockMultiplier > 1.05) m_dSystemClockMultiplier = 1.0; m_dPrevTimeHW = hwClock; m_dPrevQpcHW = hwQpc; } } else { //Log("AudioClock() returned error (0x%08x)"); } REFERENCE_TIME delta = REFERENCE_TIME(dwTime) - REFERENCE_TIME(m_dwPrevSystemTime); if(dwTime < m_dwPrevSystemTime) { delta += REFERENCE_TIME(UINT_MAX) + 1; } m_dwPrevSystemTime = dwTime; delta = (REFERENCE_TIME)(delta * (UNITS / MILLISECONDS) * m_dAdjustment * m_dBias); if (m_bHWBasedRefClock) delta *= m_dSystemClockMultiplier; //Log("mul: %.10f delta: %I64d - hwClock: %I64d hwQpc: %I64d qpc: %I64d clock diff: %I64d qpc diff: %I64d", m_dSystemClockMultiplier, delta, hwClock, hwQpc, qpcNow, hwClock - m_dStartTimeHW, hwQpc - m_dStartQpcHW); m_rtPrivateTime = m_rtPrivateTime + delta; return m_rtPrivateTime; [/code] [/QUOTE]

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