void AudioDestinationHandler::render(AudioBus* sourceBus, AudioBus* destinationBus, size_t numberOfFrames)
{
// We don't want denormals slowing down any of the audio processing
// since they can very seriously hurt performance.
// This will take care of all AudioNodes because they all process within this scope.
DenormalDisabler denormalDisabler;
// Need to check if the context actually alive. Otherwise the subsequent
// steps will fail. If the context is not alive somehow, return immediately
// and do nothing.
//
// TODO(hongchan): because the context can go away while rendering, so this
// check cannot guarantee the safe execution of the following steps.
ASSERT(context());
if (!context())
return;
context()->deferredTaskHandler().setAudioThreadToCurrentThread();
// If the destination node is not initialized, pass the silence to the final
// audio destination (one step before the FIFO). This check is for the case
// where the destination is in the middle of tearing down process.
if (!isInitialized()) {
destinationBus->zero();
return;
}
// Let the context take care of any business at the start of each render quantum.
context()->handlePreRenderTasks();
// Prepare the local audio input provider for this render quantum.
if (sourceBus)
m_localAudioInputProvider.set(sourceBus);
ASSERT(numberOfInputs() >= 1);
if (numberOfInputs() < 1) {
destinationBus->zero();
return;
}
// This will cause the node(s) connected to us to process, which in turn will pull on their input(s),
// all the way backwards through the rendering graph.
AudioBus* renderedBus = input(0).pull(destinationBus, numberOfFrames);
if (!renderedBus) {
destinationBus->zero();
} else if (renderedBus != destinationBus) {
// in-place processing was not possible - so copy
destinationBus->copyFrom(*renderedBus);
}
// Process nodes which need a little extra help because they are not connected to anything, but still need to process.
context()->deferredTaskHandler().processAutomaticPullNodes(numberOfFrames);
// Let the context take care of any business at the end of each render quantum.
context()->handlePostRenderTasks();
// Advance current sample-frame.
size_t newSampleFrame = m_currentSampleFrame + numberOfFrames;
releaseStore(&m_currentSampleFrame, newSampleFrame);
}
bool OfflineAudioDestinationHandler::renderIfNotSuspended(AudioBus* sourceBus, AudioBus* destinationBus, size_t numberOfFrames)
{
// We don't want denormals slowing down any of the audio processing
// since they can very seriously hurt performance.
// This will take care of all AudioNodes because they all process within this scope.
DenormalDisabler denormalDisabler;
context()->deferredTaskHandler().setAudioThread(currentThread());
if (!context()->isDestinationInitialized()) {
destinationBus->zero();
return false;
}
// Take care pre-render tasks at the beginning of each render quantum. Then
// it will stop the rendering loop if the context needs to be suspended
// at the beginning of the next render quantum.
if (context()->handlePreOfflineRenderTasks()) {
suspendOfflineRendering();
return true;
}
// Prepare the local audio input provider for this render quantum.
if (sourceBus)
m_localAudioInputProvider.set(sourceBus);
ASSERT(numberOfInputs() >= 1);
if (numberOfInputs() < 1) {
destinationBus->zero();
return false;
}
// This will cause the node(s) connected to us to process, which in turn will pull on their input(s),
// all the way backwards through the rendering graph.
AudioBus* renderedBus = input(0).pull(destinationBus, numberOfFrames);
if (!renderedBus) {
destinationBus->zero();
} else if (renderedBus != destinationBus) {
// in-place processing was not possible - so copy
destinationBus->copyFrom(*renderedBus);
}
// Process nodes which need a little extra help because they are not connected to anything, but still need to process.
context()->deferredTaskHandler().processAutomaticPullNodes(numberOfFrames);
// Let the context take care of any business at the end of each render quantum.
context()->handlePostOfflineRenderTasks();
// Advance current sample-frame.
size_t newSampleFrame = m_currentSampleFrame + numberOfFrames;
releaseStore(&m_currentSampleFrame, newSampleFrame);
return false;
}
void ChannelMergerHandler::process(size_t framesToProcess) {
AudioNodeOutput& output = this->output(0);
DCHECK_EQ(framesToProcess, output.bus()->length());
unsigned numberOfOutputChannels = output.numberOfChannels();
DCHECK_EQ(numberOfInputs(), numberOfOutputChannels);
// Merge multiple inputs into one output.
for (unsigned i = 0; i < numberOfOutputChannels; ++i) {
AudioNodeInput& input = this->input(i);
DCHECK_EQ(input.numberOfChannels(), 1u);
AudioChannel* outputChannel = output.bus()->channel(i);
if (input.isConnected()) {
// The mixing rules will be applied so multiple channels are down-
// mixed to mono (when the mixing rule is defined). Note that only
// the first channel will be taken for the undefined input channel
// layout.
//
// See:
// http://webaudio.github.io/web-audio-api/#channel-up-mixing-and-down-mixing
AudioChannel* inputChannel = input.bus()->channel(0);
outputChannel->copyFrom(inputChannel);
} else {
// If input is unconnected, fill zeros in the channel.
outputChannel->zero();
}
}
}
void ChannelMergerNode::process(size_t framesToProcess)
{
AudioNodeOutput* output = this->output(0);
ASSERT(output);
ASSERT_UNUSED(framesToProcess, framesToProcess == output->bus()->length());
// Output bus not updated yet, so just output silence.
if (m_desiredNumberOfOutputChannels != output->numberOfChannels()) {
output->bus()->zero();
return;
}
// Merge all the channels from all the inputs into one output.
unsigned outputChannelIndex = 0;
for (unsigned i = 0; i < numberOfInputs(); ++i) {
AudioNodeInput* input = this->input(i);
if (input->isConnected()) {
unsigned numberOfInputChannels = input->bus()->numberOfChannels();
// Merge channels from this particular input.
for (unsigned j = 0; j < numberOfInputChannels; ++j) {
AudioChannel* inputChannel = input->bus()->channel(j);
AudioChannel* outputChannel = output->bus()->channel(outputChannelIndex);
outputChannel->copyFrom(inputChannel);
++outputChannelIndex;
}
}
}
ASSERT(outputChannelIndex == output->numberOfChannels());
}
// Any time a connection or disconnection happens on any of our inputs, we potentially need to change the
// number of channels of our output.
void ChannelMergerNode::checkNumberOfChannelsForInput(AudioNodeInput* input)
{
ASSERT(context()->isAudioThread() && context()->isGraphOwner());
// Count how many channels we have all together from all of the inputs.
unsigned numberOfOutputChannels = 0;
for (unsigned i = 0; i < numberOfInputs(); ++i) {
AudioNodeInput* input = this->input(i);
if (input->isConnected())
numberOfOutputChannels += input->numberOfChannels();
}
// If the actual number of channels exceeds the max allowed, just drop the excess.
numberOfOutputChannels = std::min(numberOfOutputChannels, AudioContext::maxNumberOfChannels());
// Set the correct number of channels on the output
AudioNodeOutput* output = this->output(0);
ASSERT(output);
output->setNumberOfChannels(numberOfOutputChannels);
// There can in rare cases be a slight delay before the output bus is updated to the new number of
// channels because of tryLocks() in the context's updating system. So record the new number of
// output channels here.
m_desiredNumberOfOutputChannels = numberOfOutputChannels;
AudioNode::checkNumberOfChannelsForInput(input);
}
// Any time a connection or disconnection happens on any of our inputs, we potentially need to change the
// number of channels of our output.
void ChannelMergerNode::checkNumberOfChannelsForInput(ContextRenderLock& r, AudioNodeInput* input)
{
// Count how many channels we have all together from all of the inputs.
uint32_t numberOfOutputChannels = 0;
for (uint32_t i = 0; i < numberOfInputs(); ++i)
{
auto input = this->input(i);
if (input->isConnected())
{
numberOfOutputChannels += input->bus(r)->numberOfChannels();
}
}
// Set the correct number of channels on the output
auto output = this->output(0);
output->setNumberOfChannels(r, numberOfOutputChannels);
// Note * There can in rare cases be a slight delay before the output bus is updated to the new number of
// channels because of tryLocks() in the context's updating system. So record the new number of
// output channels here.
m_desiredNumberOfOutputChannels = numberOfOutputChannels;
AudioNode::checkNumberOfChannelsForInput(r, input);
}
// Any time a connection or disconnection happens on any of our inputs, we potentially need to change the
// number of channels of our output.
void AudioChannelMerger::checkNumberOfChannelsForInput(AudioNodeInput*)
{
ASSERT(context()->isAudioThread() && context()->isGraphOwner());
// Count how many channels we have all together from all of the inputs.
unsigned numberOfOutputChannels = 0;
for (unsigned i = 0; i < numberOfInputs(); ++i) {
AudioNodeInput* input = this->input(i);
if (input->isConnected())
numberOfOutputChannels += input->bus()->numberOfChannels();
}
// Set the correct number of channels on the output
AudioNodeOutput* output = this->output(0);
ASSERT(output);
output->setNumberOfChannels(numberOfOutputChannels);
}
void ChannelMergerNode::process(size_t framesToProcess)
{
AudioNodeOutput* output = this->output(0);
ASSERT(output);
ASSERT_UNUSED(framesToProcess, framesToProcess == output->bus()->length());
// Output bus not updated yet, so just output silence.
if (m_desiredNumberOfOutputChannels != output->numberOfChannels()) {
output->bus()->zero();
return;
}
// Merge all the channels from all the inputs into one output.
unsigned outputChannelIndex = 0;
unsigned maxAllowedOutputChannels = output->numberOfChannels();
for (unsigned i = 0; i < numberOfInputs(); ++i) {
AudioNodeInput* input = this->input(i);
if (input->isConnected()) {
unsigned numberOfInputChannels = input->bus()->numberOfChannels();
// Merge channels from this particular input, but be careful not to exceed the number of
// output channels. (This can happen if there are many inputs with each input
// containing many channels.)
for (unsigned j = 0; j < numberOfInputChannels; ++j) {
if (outputChannelIndex < maxAllowedOutputChannels) {
AudioChannel* inputChannel = input->bus()->channel(j);
AudioChannel* outputChannel = output->bus()->channel(outputChannelIndex);
outputChannel->copyFrom(inputChannel);
++outputChannelIndex;
}
}
}
if (outputChannelIndex >= maxAllowedOutputChannels)
break;
}
ASSERT(outputChannelIndex == output->numberOfChannels());
}
void ChannelMergerNode::process(ContextRenderLock& r, size_t framesToProcess)
{
auto output = this->output(0);
ASSERT_UNUSED(framesToProcess, framesToProcess == output->bus(r)->length());
// Output bus not updated yet, so just output silence. See Note * in checkNumberOfChannelsForInput
if (m_desiredNumberOfOutputChannels != output->numberOfChannels())
{
output->bus(r)->zero();
return;
}
// Merge all the channels from all the inputs into one output.
uint32_t outputChannelIndex = 0;
for (uint32_t i = 0; i < numberOfInputs(); ++i)
{
auto input = this->input(i);
if (input->isConnected())
{
uint32_t numberOfInputChannels = input->bus(r)->numberOfChannels();
// Merge channels from this particular input.
for (uint32_t j = 0; j < numberOfInputChannels; ++j)
{
AudioChannel* inputChannel = input->bus(r)->channel(j);
AudioChannel* outputChannel = output->bus(r)->channel(outputChannelIndex);
outputChannel->copyFrom(inputChannel);
++outputChannelIndex;
}
}
}
ASSERT(outputChannelIndex == output->numberOfChannels());
}
