void AudioDevicePush::PushChunkToDevice(DspChunk& chunk, CAMEvent* pFilledEvent)
{
// Get up-to-date information on the device buffer.
UINT32 bufferPadding;
ThrowIfFailed(m_backend->audioClient->GetCurrentPadding(&bufferPadding));
// Find out how many frames we can write this time.
const UINT32 doFrames = std::min(m_backend->deviceBufferSize - bufferPadding, (UINT32)chunk.GetFrameCount());
if (doFrames == 0)
return;
// Write frames to the device buffer.
BYTE* deviceBuffer;
ThrowIfFailed(m_backend->audioRenderClient->GetBuffer(doFrames, &deviceBuffer));
assert(chunk.GetFrameSize() == (m_backend->waveFormat->wBitsPerSample / 8 * m_backend->waveFormat->nChannels));
memcpy(deviceBuffer, chunk.GetData(), doFrames * chunk.GetFrameSize());
ThrowIfFailed(m_backend->audioRenderClient->ReleaseBuffer(doFrames, 0));
// If the buffer is fully filled, set the corresponding event (if requested).
if (pFilledEvent &&
bufferPadding + doFrames == m_backend->deviceBufferSize)
{
pFilledEvent->Set();
}
assert(doFrames <= chunk.GetFrameCount());
chunk.ShrinkHead(chunk.GetFrameCount() - doFrames);
m_pushedFrames += doFrames;
}
void AudioRenderer::ApplyRateCorrection(DspChunk& chunk)
{
CAutoLock objectLock(this);
assert(m_device);
assert(!m_device->IsBitstream());
assert(m_state == State_Running);
if (chunk.IsEmpty())
return;
const REFERENCE_TIME latency = llMulDiv(chunk.GetFrameCount(), OneSecond, chunk.GetRate(), 0) +
m_device->GetStreamLatency() + OneMillisecond * 10;
const REFERENCE_TIME remaining = m_device->GetEnd() - m_device->GetPosition();
REFERENCE_TIME deltaTime = 0;
if (m_live)
{
// Rate matching.
if (remaining > latency)
{
size_t dropFrames = (size_t)llMulDiv(m_device->GetWaveFormat()->nSamplesPerSec,
remaining - latency, OneSecond, 0);
dropFrames = std::min(dropFrames, chunk.GetFrameCount());
chunk.ShrinkHead(chunk.GetFrameCount() - dropFrames);
DebugOut("AudioRenderer drop", dropFrames, "frames for rate matching");
}
}
else
{
// Clock matching.
assert(m_externalClock);
REFERENCE_TIME graphTime, myTime, myStartTime;
if (SUCCEEDED(m_myClock.GetAudioClockStartTime(&myStartTime)) &&
SUCCEEDED(m_myClock.GetAudioClockTime(&myTime, nullptr)) &&
SUCCEEDED(m_graphClock->GetTime(&graphTime)) &&
myTime > myStartTime)
{
myTime -= m_device->GetSilence();
if (myTime > graphTime)
{
// Pad and adjust backwards.
REFERENCE_TIME padTime = myTime - graphTime;
assert(padTime >= 0);
size_t padFrames = (size_t)llMulDiv(m_device->GetWaveFormat()->nSamplesPerSec,
padTime, OneSecond, 0);
if (padFrames > m_device->GetWaveFormat()->nSamplesPerSec / 33) // ~30ms threshold
{
DspChunk tempChunk(chunk.GetFormat(), chunk.GetChannelCount(),
chunk.GetFrameCount() + padFrames, chunk.GetRate());
size_t padBytes = tempChunk.GetFrameSize() * padFrames;
ZeroMemory(tempChunk.GetData(), padBytes);
memcpy(tempChunk.GetData() + padBytes, chunk.GetData(), chunk.GetSize());
chunk = std::move(tempChunk);
REFERENCE_TIME paddedTime = llMulDiv(padFrames, OneSecond,
m_device->GetWaveFormat()->nSamplesPerSec, 0);
m_myClock.OffsetSlavedClock(-paddedTime);
padTime -= paddedTime;
assert(padTime >= 0);
DebugOut("AudioRenderer pad", paddedTime / 10000., "ms for clock matching at",
m_sampleCorrection.GetLastFrameEnd() / 10000., "frame position");
}
// Correct the rest with variable rate.
m_dspRealtimeRate.Adjust(padTime);
m_myClock.OffsetSlavedClock(-padTime);
}
else if (remaining > latency)
{
// Crop and adjust forwards.
assert(myTime <= graphTime);
REFERENCE_TIME dropTime = std::min(graphTime - myTime, remaining - latency);
assert(dropTime >= 0);
size_t dropFrames = (size_t)llMulDiv(m_device->GetWaveFormat()->nSamplesPerSec,
dropTime, OneSecond, 0);
dropFrames = std::min(dropFrames, chunk.GetFrameCount());
if (dropFrames > m_device->GetWaveFormat()->nSamplesPerSec / 33) // ~30ms threshold
{
chunk.ShrinkHead(chunk.GetFrameCount() - dropFrames);
REFERENCE_TIME droppedTime = llMulDiv(dropFrames, OneSecond,
m_device->GetWaveFormat()->nSamplesPerSec, 0);
m_myClock.OffsetSlavedClock(droppedTime);
dropTime -= droppedTime;
assert(dropTime >= 0);
DebugOut("AudioRenderer drop", droppedTime / 10000., "ms for clock matching at",
m_sampleCorrection.GetLastFrameEnd() / 10000., "frame position");
}
// Correct the rest with variable rate.
m_dspRealtimeRate.Adjust(-dropTime);
m_myClock.OffsetSlavedClock(dropTime);
}
}
}
}
