bool AREngine::initHardware(IOService* inProvider)
{
bool theAnswer = false;
if(IOAudioEngine::initHardware(inProvider))
{
IOAudioSampleRate theInitialSampleRate = { 0, 0 };
UInt32 theNumberChannels = 0;
// create the streams
if(CreateStreams(&theInitialSampleRate, &theNumberChannels) && (theInitialSampleRate.whole != 0))
{
CreateControls(theNumberChannels);
// figure out how long each block is in microseconds
mBlockTimeoutMicroseconds = 1000000 * mBlockSize / theInitialSampleRate.whole;
setSampleRate(&theInitialSampleRate);
// Set the number of sample frames in each buffer
setNumSampleFramesPerBuffer(mBlockSize * mNumberBlocks);
// set up the timer
IOWorkLoop* theWorkLoop = getWorkLoop();
if(theWorkLoop != NULL)
{
mTimerEventSource = IOTimerEventSource::timerEventSource(this, TimerFired);
if(mTimerEventSource != NULL)
{
theWorkLoop->addEventSource(mTimerEventSource);
theAnswer = true;
}
}
// set the safety offset
// note that due to cache issues, it probably isn't wise to leave the safety offset at 0,
// we set it to 4 here, just to be safe.
setSampleOffset(4);
// set up the time stamp generator
mTimeStampGenerator.SetSampleRate(theInitialSampleRate.whole);
mTimeStampGenerator.SetFramesPerRingBuffer(mBlockSize * mNumberBlocks);
// nate that the rate scalar is a 4.28 fixed point number
// this means that each incremnt is 1/2^28
mTimeStampGenerator.SetRateScalar(1UL << 28);
// set the maximum jitter
// AbsoluteTime theMaximumJitter = { 0, 0 };
// nanoseconds_to_absolutetime(5ULL * 1000ULL, &theMaximumJitter);
// mTimeStampGenerator.SetMaximumJitter(theMaximumJitter.lo);
}
}
return theAnswer;
}
void ossimNitfRpcBase::setSampleOffset(ossim_uint32 sampleOffset)
{
ossimString os = ossimNitfCommon::convertToUIntString(sampleOffset,
SAMPLE_OFFSET_SIZE);
setSampleOffset(os);
}
