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 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());
}
