void DriverAlsa::AudioThread()
{
try
{
for (;;)
{
Msg* msg = iPipeline.Pull();
msg = msg->Process(*this);
if (msg != NULL)
{
msg->RemoveRef();
}
AutoMutex am(iMutex);
if (iQuit)
break;
}
}
catch (ThreadKill&) {}
}
void AudioDriver::AudioThread()
{
HANDLE mmcssHandle = NULL;
DWORD mmcssTaskIndex = 0;
HRESULT hr = CoInitializeEx(NULL, COINIT_MULTITHREADED);
if (hr != S_OK)
{
Log::Print("Unable to initialize COM in render thread: %x\n", hr);
return;
}
// Gain access to the system multimedia audio endpoint and associate an
// audio client object with it.
if (InitializeAudioClient() == false)
{
goto Exit;
}
// Hook up to the Multimedia Class Scheduler Service to prioritise
// our render activities.
mmcssHandle = AvSetMmThreadCharacteristics(L"Audio", &mmcssTaskIndex);
if (mmcssHandle == NULL)
{
Log::Print("Unable to enable MMCSS on render thread: %d\n",
GetLastError());
goto Exit;
}
// Native events waited on in this thread.
HANDLE waitArray[2] = {iAudioSessionDisconnectedEvent,
iAudioSamplesReadyEvent};
// Pipeline processing loop.
try {
for (;;) {
#ifdef _TIMINGS_DEBUG
LARGE_INTEGER StartingTime, EndingTime, ElapsedMicroseconds;
LARGE_INTEGER Frequency;
QueryPerformanceFrequency(&Frequency);
QueryPerformanceCounter(&StartingTime);
#endif /* _TIMINGS_DEBUG */
TUint32 padding = 0;
//
// Calculate the number of bytes in the render buffer
// for this period.
//
// This is the maximum we will pull from the pipeline.
//
// If the Audio Engine has not been initialized yet stick with
// the default value.
//
if (iAudioEngineInitialised && ! iAudioSessionDisconnected)
{
hr = iAudioClient->GetCurrentPadding(&padding);
if (hr == S_OK)
{
iRenderBytesThisPeriod = (iBufferSize - padding) *
iFrameSize;
}
else
{
Log::Print("ERROR: Couldn't read render buffer padding\n");
iRenderBytesThisPeriod = 0;
}
iRenderBytesRemaining = iRenderBytesThisPeriod;
}
//
// Process pipeline messages until we've reached the maximum for
// this period.
//
// The pull will block if there are no messages.
//
for(;;)
{
if (iPlayable != NULL) {
ProcessAudio(iPlayable);
}
else {
Msg* msg = iPipeline.Pull();
ASSERT(msg != NULL);
msg = msg->Process(*this);
ASSERT(msg == NULL);
}
//
// Have we reached the data limit for this period or been told
// to exit ?
//
if (iPlayable != NULL || iQuit)
{
break;
}
}
if (iQuit)
{
break;
}
// Log some interesting data if we can't fill at least half
// of the available space in the render buffer.
if (iRenderBytesThisPeriod * 0.5 < iRenderBytesRemaining)
{
Log::Print("Audio period: Requested Bytes [%u] : Returned Bytes"
" [%u]\n",
iRenderBytesThisPeriod,
iRenderBytesThisPeriod - iRenderBytesRemaining);
if (iPlayable)
{
TUint bytes = iPlayable->Bytes();
if (iResamplingInput)
{
// Calculate the bytes that will be generated by the
// translation.
long long tmp = (long long)bytes *
(long long)iResampleOutputBps /
(long long)iResampleInputBps;
bytes = TUint(tmp);
// Round up to the nearest frame.
bytes += iMixFormat->nBlockAlign;
bytes -= bytes % iMixFormat->nBlockAlign;
}
Log::Print(" Available Bytes [%u]\n", bytes);
}
else
{
Log::Print(" Available Bytes [0]\n");
}
if (iAudioEngineInitialised)
{
Log::Print(" Period Start Frames In Buffer [%u]\n",
padding);
hr = iAudioClient->GetCurrentPadding(&padding);
if (hr == S_OK)
{
Log::Print(" Current Frames In Buffer [%u]\n",
padding);
}
}
}
#ifdef _TIMINGS_DEBUG
QueryPerformanceCounter(&EndingTime);
ElapsedMicroseconds.QuadPart = EndingTime.QuadPart -
StartingTime.QuadPart;
//
// We now have the elapsed number of ticks, along with the
// number of ticks-per-second. We use these values
// to convert to the number of elapsed microseconds.
// To guard against loss-of-precision, we convert
// to microseconds *before* dividing by ticks-per-second.
//
ElapsedMicroseconds.QuadPart *= 1000000;
ElapsedMicroseconds.QuadPart /= Frequency.QuadPart;
Log::Print("Time To Process Messages This Audio Period [%lld us]\n",
ElapsedMicroseconds.QuadPart);
#endif /* _TIMINGS_DEBUG */
// The audio client isn't capable of playing this stream.
// Continue to pull from pipeline until the next playable
// stream is available.
if (! iStreamFormatSupported)
{
continue;
}
// The audio session has been disconnected.
// Continue to pull from pipeline until we are instructed to quit.
if (iAudioSessionDisconnected)
{
continue;
}
//
// Start the Audio client once we have pre-loaded some
// data to the render buffer.
//
// This will prevent any initial audio glitches..
//
if (! iAudioClientStarted)
{
// There was no data read this period so try again next period.
if (iRenderBytesThisPeriod == iRenderBytesRemaining)
{
continue;
}
hr = iAudioClient->Start();
if (hr != S_OK)
{
Log::Print("Unable to start render client: %x.\n", hr);
break;
}
iAudioClientStarted = true;
}
// Apply any volume changes
if (iAudioClientStarted && iVolumeChanged)
{
iAudioSessionVolume->SetMasterVolume(iVolumeLevel, NULL);
iVolumeChanged = false;
}
// Wait for a kick from the native audio engine.
DWORD waitResult =
WaitForMultipleObjects(2, waitArray, FALSE, INFINITE);
switch (waitResult) {
case WAIT_OBJECT_0 + 0: // iAudioSessionDisconnectedEvent
// Stop the audio client
iAudioClient->Stop();
iAudioClient->Reset();
iAudioClientStarted = false;
iAudioSessionDisconnected = true;
break;
case WAIT_OBJECT_0 + 1: // iAudioSamplesReadyEvent
break;
default:
Log::Print("ERROR: Unexpected event received [%d]\n",
waitResult);
}
}
}
catch (ThreadKill&) {}
Exit:
// Complete any previous resampling session.
if (iResamplingInput)
{
WWMFSampleData sampleData;
hr = iResampler.Drain((iBufferSize * iFrameSize), &sampleData);
if (hr == S_OK)
{
Log::Print("Resampler drained correctly [%d bytes].\n",
sampleData.bytes);
sampleData.Release();
}
else
{
Log::Print("Resampler drain failed.\n");
}
}
iResampler.Finalize();
// Now we've stopped reading the pipeline, stop the native audio.
StopAudioEngine();
// Free up native resources.
ShutdownAudioEngine();
// Unhook from MMCSS.
AvRevertMmThreadCharacteristics(mmcssHandle);
CoUninitialize();
}
