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 /*

  * Copyright (C) 2010, Google Inc. All rights reserved.

  *

  * Redistribution and use in source and binary forms, with or without

  * modification, are permitted provided that the following conditions

  * are met:

  * 1.  Redistributions of source code must retain the above copyright

  *    notice, this list of conditions and the following disclaimer.

  * 2.  Redistributions in binary form must reproduce the above copyright

  *    notice, this list of conditions and the following disclaimer in the

  *    documentation and/or other materials provided with the distribution.

  *

  * THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS'' AND ANY

  * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED

  * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE

  * DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS BE LIABLE FOR ANY

  * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES

  * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;

  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON

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 #include "HRTFPanner.h"

 #include "HRTFDatabaseLoader.h"

 #include "FFTConvolver.h"

 #include "HRTFDatabase.h"

 using namespace std;

 using namespace mozilla;

 using dom::ChannelInterpretation;

 namespace WebCore {

 // The value of 2 milliseconds is larger than the largest delay which exists in any HRTFKernel from the default HRTFDatabase (0.0136 seconds).

 // We ASSERT the delay values used in process() with this value.

 const double MaxDelayTimeSeconds = 0.002;

 const int UninitializedAzimuth = -1;

 const unsigned RenderingQuantum = WEBAUDIO_BLOCK_SIZE;

 HRTFPanner::HRTFPanner(float sampleRate, mozilla::TemporaryRef<HRTFDatabaseLoader> databaseLoader)

     : m_databaseLoader(databaseLoader)

     , m_sampleRate(sampleRate)

     , m_crossfadeSelection(CrossfadeSelection1)

     , m_azimuthIndex1(UninitializedAzimuth)

     , m_azimuthIndex2(UninitializedAzimuth)

     // m_elevation1 and m_elevation2 are initialized in pan()

     , m_crossfadeX(0)

     , m_crossfadeIncr(0)

     , m_convolverL1(HRTFElevation::fftSizeForSampleRate(sampleRate))

     , m_convolverR1(m_convolverL1.fftSize())

     , m_convolverL2(m_convolverL1.fftSize())

     , m_convolverR2(m_convolverL1.fftSize())

     , m_delayLine(MaxDelayTimeSeconds * sampleRate, 1.0)

 {

     MOZ_ASSERT(m_databaseLoader);

     MOZ_COUNT_CTOR(HRTFPanner);

     m_tempL1.SetLength(RenderingQuantum);

     m_tempR1.SetLength(RenderingQuantum);

     m_tempL2.SetLength(RenderingQuantum);

     m_tempR2.SetLength(RenderingQuantum);

 }

 HRTFPanner::~HRTFPanner()

 {

     MOZ_COUNT_DTOR(HRTFPanner);

 }

 size_t HRTFPanner::sizeOfIncludingThis(mozilla::MallocSizeOf aMallocSizeOf) const

 {

     size_t amount = aMallocSizeOf(this);

     if (m_databaseLoader) {

         m_databaseLoader->sizeOfIncludingThis(aMallocSizeOf);

     }

     amount += m_convolverL1.sizeOfExcludingThis(aMallocSizeOf);

     amount += m_convolverR1.sizeOfExcludingThis(aMallocSizeOf);

     amount += m_convolverL2.sizeOfExcludingThis(aMallocSizeOf);

     amount += m_convolverR2.sizeOfExcludingThis(aMallocSizeOf);

     amount += m_delayLine.SizeOfExcludingThis(aMallocSizeOf);

     amount += m_tempL1.SizeOfExcludingThis(aMallocSizeOf);

     amount += m_tempL2.SizeOfExcludingThis(aMallocSizeOf);

     amount += m_tempR1.SizeOfExcludingThis(aMallocSizeOf);

     amount += m_tempR2.SizeOfExcludingThis(aMallocSizeOf);

     return amount;

 }

 void HRTFPanner::reset()

 {

     m_azimuthIndex1 = UninitializedAzimuth;

     m_azimuthIndex2 = UninitializedAzimuth;

     // m_elevation1 and m_elevation2 are initialized in pan()

     m_crossfadeSelection = CrossfadeSelection1;

     m_crossfadeX = 0.0f;

     m_crossfadeIncr = 0.0f;

     m_convolverL1.reset();

     m_convolverR1.reset();

     m_convolverL2.reset();

     m_convolverR2.reset();

     m_delayLine.Reset();

 }

 int HRTFPanner::calculateDesiredAzimuthIndexAndBlend(double azimuth, double& azimuthBlend)

 {

     // Convert the azimuth angle from the range -180 -> +180 into the range 0 -> 360.

     // The azimuth index may then be calculated from this positive value.

     if (azimuth < 0)

         azimuth += 360.0;

     HRTFDatabase* database = m_databaseLoader->database();

     MOZ_ASSERT(database);

     int numberOfAzimuths = database->numberOfAzimuths();

     const double angleBetweenAzimuths = 360.0 / numberOfAzimuths;

     // Calculate the azimuth index and the blend (0 -> 1) for interpolation.

     double desiredAzimuthIndexFloat = azimuth / angleBetweenAzimuths;

     int desiredAzimuthIndex = static_cast<int>(desiredAzimuthIndexFloat);

     azimuthBlend = desiredAzimuthIndexFloat - static_cast<double>(desiredAzimuthIndex);

     // We don't immediately start using this azimuth index, but instead approach this index from the last index we rendered at.

     // This minimizes the clicks and graininess for moving sources which occur otherwise.

     desiredAzimuthIndex = max(0, desiredAzimuthIndex);

     desiredAzimuthIndex = min(numberOfAzimuths - 1, desiredAzimuthIndex);

     return desiredAzimuthIndex;

 }

 void HRTFPanner::pan(double desiredAzimuth, double elevation, const AudioChunk* inputBus, AudioChunk* outputBus)

 {

 #ifdef DEBUG

     unsigned numInputChannels =

         inputBus->IsNull() ? 0 : inputBus->mChannelData.Length();

     MOZ_ASSERT(numInputChannels <= 2);

     MOZ_ASSERT(inputBus->mDuration == WEBAUDIO_BLOCK_SIZE);

 #endif

     bool isOutputGood = outputBus && outputBus->mChannelData.Length() == 2 && outputBus->mDuration == WEBAUDIO_BLOCK_SIZE;

     MOZ_ASSERT(isOutputGood);

     if (!isOutputGood) {

         if (outputBus)

             outputBus->SetNull(outputBus->mDuration);

         return;

     }

     HRTFDatabase* database = m_databaseLoader->database();

     if (!database) { // not yet loaded

         outputBus->SetNull(outputBus->mDuration);

         return;

     }

     // IRCAM HRTF azimuths values from the loaded database is reversed from the panner's notion of azimuth.

     double azimuth = -desiredAzimuth;

     bool isAzimuthGood = azimuth >= -180.0 && azimuth <= 180.0;

     MOZ_ASSERT(isAzimuthGood);

     if (!isAzimuthGood) {

         outputBus->SetNull(outputBus->mDuration);

         return;

     }

     // Normally, we'll just be dealing with mono sources.

     // If we have a stereo input, implement stereo panning with left source processed by left HRTF, and right source by right HRTF.

     // Get destination pointers.

     float* destinationL =

         static_cast<float*>(const_cast<void*>(outputBus->mChannelData[0]));

     float* destinationR =

         static_cast<float*>(const_cast<void*>(outputBus->mChannelData[1]));

     double azimuthBlend;

     int desiredAzimuthIndex = calculateDesiredAzimuthIndexAndBlend(azimuth, azimuthBlend);

     // Initially snap azimuth and elevation values to first values encountered.

     if (m_azimuthIndex1 == UninitializedAzimuth) {

         m_azimuthIndex1 = desiredAzimuthIndex;

         m_elevation1 = elevation;

     }

     if (m_azimuthIndex2 == UninitializedAzimuth) {

         m_azimuthIndex2 = desiredAzimuthIndex;

         m_elevation2 = elevation;

     }

     // Cross-fade / transition over a period of around 45 milliseconds.

     // This is an empirical value tuned to be a reasonable trade-off between

     // smoothness and speed.

     const double fadeFrames = sampleRate() <= 48000 ? 2048 : 4096;

     // Check for azimuth and elevation changes, initiating a cross-fade if needed.

     if (!m_crossfadeX && m_crossfadeSelection == CrossfadeSelection1) {

         if (desiredAzimuthIndex != m_azimuthIndex1 || elevation != m_elevation1) {

             // Cross-fade from 1 -> 2

             m_crossfadeIncr = 1 / fadeFrames;

             m_azimuthIndex2 = desiredAzimuthIndex;

             m_elevation2 = elevation;

         }

     }

     if (m_crossfadeX == 1 && m_crossfadeSelection == CrossfadeSelection2) {

         if (desiredAzimuthIndex != m_azimuthIndex2 || elevation != m_elevation2) {

             // Cross-fade from 2 -> 1

             m_crossfadeIncr = -1 / fadeFrames;

             m_azimuthIndex1 = desiredAzimuthIndex;

             m_elevation1 = elevation;

         }

     }

     // Get the HRTFKernels and interpolated delays.

     HRTFKernel* kernelL1;

     HRTFKernel* kernelR1;

     HRTFKernel* kernelL2;

     HRTFKernel* kernelR2;

     double frameDelayL1;

     double frameDelayR1;

     double frameDelayL2;

     double frameDelayR2;

     database->getKernelsFromAzimuthElevation(azimuthBlend, m_azimuthIndex1, m_elevation1, kernelL1, kernelR1, frameDelayL1, frameDelayR1);

     database->getKernelsFromAzimuthElevation(azimuthBlend, m_azimuthIndex2, m_elevation2, kernelL2, kernelR2, frameDelayL2, frameDelayR2);

     bool areKernelsGood = kernelL1 && kernelR1 && kernelL2 && kernelR2;

     MOZ_ASSERT(areKernelsGood);

     if (!areKernelsGood) {

         outputBus->SetNull(outputBus->mDuration);

         return;

     }

     MOZ_ASSERT(frameDelayL1 / sampleRate() < MaxDelayTimeSeconds && frameDelayR1 / sampleRate() < MaxDelayTimeSeconds);

     MOZ_ASSERT(frameDelayL2 / sampleRate() < MaxDelayTimeSeconds && frameDelayR2 / sampleRate() < MaxDelayTimeSeconds);

     // Crossfade inter-aural delays based on transitions.

     double frameDelaysL[WEBAUDIO_BLOCK_SIZE];

     double frameDelaysR[WEBAUDIO_BLOCK_SIZE];

     {

       float x = m_crossfadeX;

       float incr = m_crossfadeIncr;

       for (unsigned i = 0; i < WEBAUDIO_BLOCK_SIZE; ++i) {

         frameDelaysL[i] = (1 - x) * frameDelayL1 + x * frameDelayL2;

         frameDelaysR[i] = (1 - x) * frameDelayR1 + x * frameDelayR2;

         x += incr;

       }

     }

     // First run through delay lines for inter-aural time difference.

     m_delayLine.Write(*inputBus);

     // "Speakers" means a mono input is read into both outputs (with possibly

     // different delays).

     m_delayLine.ReadChannel(frameDelaysL, outputBus, 0,

                             ChannelInterpretation::Speakers);

     m_delayLine.ReadChannel(frameDelaysR, outputBus, 1,

                             ChannelInterpretation::Speakers);

     m_delayLine.NextBlock();

     bool needsCrossfading = m_crossfadeIncr;

     // Have the convolvers render directly to the final destination if we're not cross-fading.

     float* convolutionDestinationL1 = needsCrossfading ? m_tempL1.Elements() : destinationL;

     float* convolutionDestinationR1 = needsCrossfading ? m_tempR1.Elements() : destinationR;

     float* convolutionDestinationL2 = needsCrossfading ? m_tempL2.Elements() : destinationL;

     float* convolutionDestinationR2 = needsCrossfading ? m_tempR2.Elements() : destinationR;

     // Now do the convolutions.

     // Note that we avoid doing convolutions on both sets of convolvers if we're not currently cross-fading.

     if (m_crossfadeSelection == CrossfadeSelection1 || needsCrossfading) {

         m_convolverL1.process(kernelL1->fftFrame(), destinationL, convolutionDestinationL1, WEBAUDIO_BLOCK_SIZE);

         m_convolverR1.process(kernelR1->fftFrame(), destinationR, convolutionDestinationR1, WEBAUDIO_BLOCK_SIZE);

     }

     if (m_crossfadeSelection == CrossfadeSelection2 || needsCrossfading) {

         m_convolverL2.process(kernelL2->fftFrame(), destinationL, convolutionDestinationL2, WEBAUDIO_BLOCK_SIZE);

         m_convolverR2.process(kernelR2->fftFrame(), destinationR, convolutionDestinationR2, WEBAUDIO_BLOCK_SIZE);

     }

     if (needsCrossfading) {

         // Apply linear cross-fade.

         float x = m_crossfadeX;

         float incr = m_crossfadeIncr;

         for (unsigned i = 0; i < WEBAUDIO_BLOCK_SIZE; ++i) {

             destinationL[i] = (1 - x) * convolutionDestinationL1[i] + x * convolutionDestinationL2[i];

             destinationR[i] = (1 - x) * convolutionDestinationR1[i] + x * convolutionDestinationR2[i];

             x += incr;

         }

         // Update cross-fade value from local.

         m_crossfadeX = x;

         if (m_crossfadeIncr > 0 && fabs(m_crossfadeX - 1) < m_crossfadeIncr) {

             // We've fully made the crossfade transition from 1 -> 2.

             m_crossfadeSelection = CrossfadeSelection2;

             m_crossfadeX = 1;

             m_crossfadeIncr = 0;

         } else if (m_crossfadeIncr < 0 && fabs(m_crossfadeX) < -m_crossfadeIncr) {

             // We've fully made the crossfade transition from 2 -> 1.

             m_crossfadeSelection = CrossfadeSelection1;

             m_crossfadeX = 0;

             m_crossfadeIncr = 0;

         }

     }

 }

 int HRTFPanner::maxTailFrames() const

 {

     // Although the ideal tail time would be the length of the impulse

     // response, there is additional tail time from the approximations in the

     // implementation.  Because HRTFPanner is implemented with a DelayKernel

     // and a FFTConvolver, the tailTime of the HRTFPanner is the sum of the

     // tailTime of the DelayKernel and the tailTime of the FFTConvolver.

     // The FFTConvolver has a tail time of fftSize(), including latency of

     // fftSize()/2.

     return m_delayLine.MaxDelayTicks() + fftSize();

 }

 } // namespace WebCore