long
AudioCallbackDriver::DataCallback(AudioDataValue* aBuffer, long aFrames)
{
bool stillProcessing;
if (mPauseRequested) {
PodZero(aBuffer, aFrames * mGraphImpl->AudioChannelCount());
return aFrames;
}
#ifdef XP_MACOSX
if (OSXDeviceSwitchingWorkaround()) {
PodZero(aBuffer, aFrames * mGraphImpl->AudioChannelCount());
return aFrames;
}
#endif
#ifdef DEBUG
// DebugOnly<> doesn't work here... it forces an initialization that will cause
// mInCallback to be set back to false before we exit the statement. Do it by
// hand instead.
AutoInCallback aic(this);
#endif
GraphTime stateComputedTime = StateComputedTime();
if (stateComputedTime == 0) {
MonitorAutoLock mon(mGraphImpl->GetMonitor());
// Because this function is called during cubeb_stream_init (to prefill the
// audio buffers), it can be that we don't have a message here (because this
// driver is the first one for this graph), and the graph would exit. Simply
// return here until we have messages.
if (!mGraphImpl->MessagesQueued()) {
PodZero(aBuffer, aFrames * mGraphImpl->AudioChannelCount());
return aFrames;
}
mGraphImpl->SwapMessageQueues();
}
uint32_t durationMS = aFrames * 1000 / mSampleRate;
// For now, simply average the duration with the previous
// duration so there is some damping against sudden changes.
if (!mIterationDurationMS) {
mIterationDurationMS = durationMS;
} else {
mIterationDurationMS = (mIterationDurationMS*3) + durationMS;
mIterationDurationMS /= 4;
}
mBuffer.SetBuffer(aBuffer, aFrames);
// fill part or all with leftover data from last iteration (since we
// align to Audio blocks)
mScratchBuffer.Empty(mBuffer);
// if we totally filled the buffer (and mScratchBuffer isn't empty),
// we don't need to run an iteration and if we do so we may overflow.
if (mBuffer.Available()) {
// State computed time is decided by the audio callback's buffer length. We
// compute the iteration start and end from there, trying to keep the amount
// of buffering in the graph constant.
GraphTime nextStateComputedTime =
mGraphImpl->RoundUpToNextAudioBlock(stateComputedTime + mBuffer.Available());
mIterationStart = mIterationEnd;
// inGraph is the number of audio frames there is between the state time and
// the current time, i.e. the maximum theoretical length of the interval we
// could use as [mIterationStart; mIterationEnd].
GraphTime inGraph = stateComputedTime - mIterationStart;
// We want the interval [mIterationStart; mIterationEnd] to be before the
// interval [stateComputedTime; nextStateComputedTime]. We also want
// the distance between these intervals to be roughly equivalent each time, to
// ensure there is no clock drift between current time and state time. Since
// we can't act on the state time because we have to fill the audio buffer, we
// reclock the current time against the state time, here.
mIterationEnd = mIterationStart + 0.8 * inGraph;
STREAM_LOG(LogLevel::Debug, ("interval[%ld; %ld] state[%ld; %ld] (frames: %ld) (durationMS: %u) (duration ticks: %ld)\n",
(long)mIterationStart, (long)mIterationEnd,
(long)stateComputedTime, (long)nextStateComputedTime,
(long)aFrames, (uint32_t)durationMS,
(long)(nextStateComputedTime - stateComputedTime)));
mCurrentTimeStamp = TimeStamp::Now();
if (stateComputedTime < mIterationEnd) {
STREAM_LOG(LogLevel::Warning, ("Media graph global underrun detected"));
mIterationEnd = stateComputedTime;
}
stillProcessing = mGraphImpl->OneIteration(nextStateComputedTime);
} else {
NS_WARNING("DataCallback buffer filled entirely from scratch buffer, skipping iteration.");
stillProcessing = true;
}
mBuffer.BufferFilled();
if (mNextDriver && stillProcessing) {
{
// If the audio stream has not been started by the previous driver or
// the graph itself, keep it alive.
MonitorAutoLock mon(mGraphImpl->GetMonitor());
if (!IsStarted()) {
return aFrames;
}
}
STREAM_LOG(LogLevel::Debug, ("Switching to system driver."));
mNextDriver->SetGraphTime(this, mIterationStart, mIterationEnd);
mGraphImpl->SetCurrentDriver(mNextDriver);
mNextDriver->Start();
// Returning less than aFrames starts the draining and eventually stops the
// audio thread. This function will never get called again.
return aFrames - 1;
}
if (!stillProcessing) {
LIFECYCLE_LOG("Stopping audio thread for MediaStreamGraph %p", this);
return aFrames - 1;
}
return aFrames;
}
long
AudioCallbackDriver::DataCallback(AudioDataValue* aBuffer, long aFrames)
{
bool stillProcessing;
if (mPauseRequested) {
PodZero(aBuffer, aFrames * mGraphImpl->AudioChannelCount());
return aFrames;
}
DebugOnly<AutoInCallback> aic(AutoInCallback(this));
if (mStateComputedTime == 0) {
MonitorAutoLock mon(mGraphImpl->GetMonitor());
// Because this function is called during cubeb_stream_init (to prefill the
// audio buffers), it can be that we don't have a message here (because this
// driver is the first one for this graph), and the graph would exit. Simply
// return here until we have messages.
if (!mGraphImpl->MessagesQueued()) {
PodZero(aBuffer, aFrames * mGraphImpl->AudioChannelCount());
return aFrames;
}
mGraphImpl->SwapMessageQueues();
}
uint32_t durationMS = aFrames * 1000 / mSampleRate;
// For now, simply average the duration with the previous
// duration so there is some damping against sudden changes.
if (!mIterationDurationMS) {
mIterationDurationMS = durationMS;
} else {
mIterationDurationMS += durationMS;
mIterationDurationMS /= 2;
}
mBuffer.SetBuffer(aBuffer, aFrames);
mScratchBuffer.Empty(mBuffer);
mStateComputedTime = mNextStateComputedTime;
// State computed time is decided by the audio callback's buffer length. We
// compute the iteration start and end from there, trying to keep the amount
// of buffering in the graph constant.
mNextStateComputedTime =
mGraphImpl->RoundUpToNextAudioBlock(mStateComputedTime + mBuffer.Available());
mIterationStart = mIterationEnd;
// inGraph is the number of audio frames there is between the state time and
// the current time, i.e. the maximum theoretical length of the interval we
// could use as [mIterationStart; mIterationEnd].
GraphTime inGraph = mStateComputedTime - mIterationStart;
// We want the interval [mIterationStart; mIterationEnd] to be before the
// interval [mStateComputedTime; mNextStateComputedTime]. We also want
// the distance between these intervals to be roughly equivalent each time, to
// ensure there is no clock drift between current time and state time. Since
// we can't act on the state time because we have to fill the audio buffer, we
// reclock the current time against the state time, here.
mIterationEnd = mIterationStart + 0.8 * inGraph;
STREAM_LOG(PR_LOG_DEBUG, ("interval[%ld; %ld] state[%ld; %ld] (frames: %ld) (durationMS: %u) (duration ticks: %ld)\n",
(long)mIterationStart, (long)mIterationEnd,
(long)mStateComputedTime, (long)mNextStateComputedTime,
(long)aFrames, (uint32_t)durationMS,
(long)(mNextStateComputedTime - mStateComputedTime)));
mCurrentTimeStamp = TimeStamp::Now();
if (mStateComputedTime < mIterationEnd) {
STREAM_LOG(PR_LOG_WARNING, ("Media graph global underrun detected"));
mIterationEnd = mStateComputedTime;
}
stillProcessing = mGraphImpl->OneIteration(mIterationStart,
mIterationEnd,
mStateComputedTime,
mNextStateComputedTime);
mBuffer.BufferFilled();
if (mNextDriver && stillProcessing) {
{
// If the audio stream has not been started by the previous driver or
// the graph itself, keep it alive.
MonitorAutoLock mon(mGraphImpl->GetMonitor());
if (!IsStarted()) {
return aFrames;
}
}
STREAM_LOG(PR_LOG_DEBUG, ("Switching to system driver."));
mNextDriver->SetGraphTime(this, mIterationStart, mIterationEnd,
mStateComputedTime, mNextStateComputedTime);
mGraphImpl->SetCurrentDriver(mNextDriver);
mNextDriver->Start();
// Returning less than aFrames starts the draining and eventually stops the
// audio thread. This function will never get called again.
return aFrames - 1;
}
if (!stillProcessing) {
LIFECYCLE_LOG("Stopping audio thread for MediaStreamGraph %p", this);
return aFrames - 1;
}
return aFrames;
}
