media/webaudio/IIRFilterNode.cpp

/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim:set ts=2 sw=2 sts=2 et cindent: */
/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

#include "IIRFilterNode.h"
#include "AudioNodeEngine.h"

#include "blink/IIRFilter.h"

#include "nsGkAtoms.h"

namespace mozilla {
namespace dom {

NS_IMPL_ISUPPORTS_INHERITED0(IIRFilterNode, AudioNode)

class IIRFilterNodeEngine final : public AudioNodeEngine
{
public:
  IIRFilterNodeEngine(AudioNode* aNode, AudioDestinationNode* aDestination,
                      const AudioDoubleArray &aFeedforward,
                      const AudioDoubleArray &aFeedback,
                      uint64_t aWindowID)
    : AudioNodeEngine(aNode)
    , mDestination(aDestination->Stream())
    , mFeedforward(aFeedforward)
    , mFeedback(aFeedback)
    , mWindowID(aWindowID)
  {
  }

  void ProcessBlock(AudioNodeStream* aStream,
                    GraphTime aFrom,
                    const AudioBlock& aInput,
                    AudioBlock* aOutput,
                    bool* aFinished) override
  {
    float inputBuffer[WEBAUDIO_BLOCK_SIZE + 4];
    float* alignedInputBuffer = ALIGNED16(inputBuffer);
    ASSERT_ALIGNED16(alignedInputBuffer);

    if (aInput.IsNull()) {
      if (!mIIRFilters.IsEmpty()) {
        bool allZero = true;
        for (uint32_t i = 0; i < mIIRFilters.Length(); ++i) {
          allZero &= mIIRFilters[i]->buffersAreZero();
        }

        // all filter buffer values are zero, so the output will be zero
        // as well.
        if (allZero) {
          mIIRFilters.Clear();
          aStream->ScheduleCheckForInactive();

          RefPtr<PlayingRefChangeHandler> refchanged =
            new PlayingRefChangeHandler(aStream, PlayingRefChangeHandler::RELEASE);
          aStream->Graph()->
            DispatchToMainThreadAfterStreamStateUpdate(refchanged.forget());

          aOutput->SetNull(WEBAUDIO_BLOCK_SIZE);
          return;
        }

        PodZero(alignedInputBuffer, WEBAUDIO_BLOCK_SIZE);
      }
    } else if(mIIRFilters.Length() != aInput.ChannelCount()){
      if (mIIRFilters.IsEmpty()) {
        RefPtr<PlayingRefChangeHandler> refchanged =
          new PlayingRefChangeHandler(aStream, PlayingRefChangeHandler::ADDREF);
        aStream->Graph()->
          DispatchToMainThreadAfterStreamStateUpdate(refchanged.forget());
      } else {
        WebAudioUtils::LogToDeveloperConsole(mWindowID,
                                             "IIRFilterChannelCountChangeWarning");
      }

      // Adjust the number of filters based on the number of channels
      mIIRFilters.SetLength(aInput.ChannelCount());
      for (size_t i = 0; i < aInput.ChannelCount(); ++i) {
        mIIRFilters[i] = new blink::IIRFilter(&mFeedforward, &mFeedback);
      }
    }

    uint32_t numberOfChannels = mIIRFilters.Length();
    aOutput->AllocateChannels(numberOfChannels);

    for (uint32_t i = 0; i < numberOfChannels; ++i) {
      const float* input;
      if (aInput.IsNull()) {
        input = alignedInputBuffer;
      } else {
        input = static_cast<const float*>(aInput.mChannelData[i]);
        if (aInput.mVolume != 1.0) {
          AudioBlockCopyChannelWithScale(input, aInput.mVolume, alignedInputBuffer);
          input = alignedInputBuffer;
        }
      }

      mIIRFilters[i]->process(input,
                              aOutput->ChannelFloatsForWrite(i),
                              aInput.GetDuration());
    }
  }

  bool IsActive() const override
  {
    return !mIIRFilters.IsEmpty();
  }

  size_t SizeOfExcludingThis(MallocSizeOf aMallocSizeOf) const override
  {
    // Not owned:
    // - mDestination - probably not owned
    // - AudioParamTimelines - counted in the AudioNode
    size_t amount = AudioNodeEngine::SizeOfExcludingThis(aMallocSizeOf);
    amount += mIIRFilters.ShallowSizeOfExcludingThis(aMallocSizeOf);
    return amount;
  }

  size_t SizeOfIncludingThis(MallocSizeOf aMallocSizeOf) const override
  {
    return aMallocSizeOf(this) + SizeOfExcludingThis(aMallocSizeOf);
  }

private:
  AudioNodeStream* mDestination;
  nsTArray<nsAutoPtr<blink::IIRFilter>> mIIRFilters;
  AudioDoubleArray mFeedforward;
  AudioDoubleArray mFeedback;
  uint64_t mWindowID;
};

IIRFilterNode::IIRFilterNode(AudioContext* aContext,
                             const mozilla::dom::binding_detail::AutoSequence<double>& aFeedforward,
                             const mozilla::dom::binding_detail::AutoSequence<double>& aFeedback)
  : AudioNode(aContext,
              2,
              ChannelCountMode::Max,
              ChannelInterpretation::Speakers)
{
  mFeedforward.SetLength(aFeedforward.Length());
  PodCopy(mFeedforward.Elements(), aFeedforward.Elements(), aFeedforward.Length());
  mFeedback.SetLength(aFeedback.Length());
  PodCopy(mFeedback.Elements(), aFeedback.Elements(), aFeedback.Length());

  // Scale coefficients -- we guarantee that mFeedback != 0 when creating
  // the IIRFilterNode.
  double scale = mFeedback[0];
  double* elements = mFeedforward.Elements();
  for (size_t i = 0; i < mFeedforward.Length(); ++i) {
    elements[i] /= scale;
  }

  elements = mFeedback.Elements();
  for (size_t i = 0; i < mFeedback.Length(); ++i) {
    elements[i] /= scale;
  }

  // We check that this is exactly equal to one later in blink/IIRFilter.cpp
  elements[0] = 1.0;

  uint64_t windowID = aContext->GetParentObject()->WindowID();
  IIRFilterNodeEngine* engine = new IIRFilterNodeEngine(this, aContext->Destination(), mFeedforward, mFeedback, windowID);
  mStream = AudioNodeStream::Create(aContext, engine,
                                    AudioNodeStream::NO_STREAM_FLAGS,
                                    aContext->Graph());
}

IIRFilterNode::~IIRFilterNode()
{
}

size_t
IIRFilterNode::SizeOfExcludingThis(MallocSizeOf aMallocSizeOf) const
{
  size_t amount = AudioNode::SizeOfExcludingThis(aMallocSizeOf);
  return amount;
}

size_t
IIRFilterNode::SizeOfIncludingThis(MallocSizeOf aMallocSizeOf) const
{
  return aMallocSizeOf(this) + SizeOfExcludingThis(aMallocSizeOf);
}

JSObject*
IIRFilterNode::WrapObject(JSContext* aCx, JS::Handle<JSObject*> aGivenProto)
{
  return IIRFilterNodeBinding::Wrap(aCx, this, aGivenProto);
}

void
IIRFilterNode::GetFrequencyResponse(const Float32Array& aFrequencyHz,
                                    const Float32Array& aMagResponse,
                                    const Float32Array& aPhaseResponse)
{
  aFrequencyHz.ComputeLengthAndData();
  aMagResponse.ComputeLengthAndData();
  aPhaseResponse.ComputeLengthAndData();

  uint32_t length = std::min(std::min(aFrequencyHz.Length(),
                                      aMagResponse.Length()),
                             aPhaseResponse.Length());
  if (!length) {
    return;
  }

  auto frequencies = MakeUnique<float[]>(length);
  float* frequencyHz = aFrequencyHz.Data();
  const double nyquist = Context()->SampleRate() * 0.5;

  // Normalize the frequencies
  for (uint32_t i = 0; i < length; ++i) {
    if (frequencyHz[i] >= 0 && frequencyHz[i] <= nyquist) {
        frequencies[i] = static_cast<float>(frequencyHz[i] / nyquist);
    } else {
        frequencies[i] = std::numeric_limits<float>::quiet_NaN();
    }
  }

  blink::IIRFilter filter(&mFeedforward, &mFeedback);
  filter.getFrequencyResponse(int(length), frequencies.get(), aMagResponse.Data(), aPhaseResponse.Data());
}

} // namespace dom
} // namespace mozilla