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/*
* Copyright (C) 2010 Google Inc. All rights reserved.
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* modification, are permitted provided that the following conditions
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*
* THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "AS IS" AND ANY
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#include "config.h"
#if ENABLE(WEB_AUDIO)
#include "HRTFElevation.h"
#include "AudioBus.h"
#include "AudioFileReader.h"
#include "Biquad.h"
#include "FFTFrame.h"
#include "HRTFDatabaseLoader.h"
#include "HRTFPanner.h"
#include <algorithm>
#include <math.h>
#include <wtf/NeverDestroyed.h>
namespace WebCore {
// Total number of components of an HRTF database.
constexpr size_t TotalNumberOfResponses = 240;
// Number of frames in an individual impulse response.
constexpr size_t ResponseFrameSize = 256;
// Sample-rate of the spatialization impulse responses as stored in the resource file.
// The impulse responses may be resampled to a different sample-rate (depending on the audio hardware) when they are loaded.
constexpr float ResponseSampleRate = 44100;
#if PLATFORM(COCOA) || USE(GSTREAMER)
#define USE_CONCATENATED_IMPULSE_RESPONSES
#endif
#ifdef USE_CONCATENATED_IMPULSE_RESPONSES
// Lazily load a concatenated HRTF database for given subject and store it in a
// local hash table to ensure quick efficient future retrievals.
static AudioBus* getConcatenatedImpulseResponsesForSubject(const String& subjectName)
{
typedef HashMap<String, AudioBus*> AudioBusMap;
static NeverDestroyed<AudioBusMap> audioBusMap;
AudioBus* bus;
AudioBusMap::iterator iterator = audioBusMap.get().find(subjectName);
if (iterator == audioBusMap.get().end()) {
auto concatenatedImpulseResponses = AudioBus::loadPlatformResource(subjectName.utf8().data(), ResponseSampleRate);
ASSERT(concatenatedImpulseResponses);
if (!concatenatedImpulseResponses)
return 0;
bus = concatenatedImpulseResponses.leakRef();
audioBusMap.get().set(subjectName, bus);
} else
bus = iterator->value;
size_t responseLength = bus->length();
size_t expectedLength = static_cast<size_t>(TotalNumberOfResponses * ResponseFrameSize);
// Check number of channels and length. For now these are fixed and known.
bool isBusGood = responseLength == expectedLength && bus->numberOfChannels() == 2;
ASSERT(isBusGood);
if (!isBusGood)
return 0;
return bus;
}
#endif
// Takes advantage of the symmetry and creates a composite version of the two measured versions. For example, we have both azimuth 30 and -30 degrees
// where the roles of left and right ears are reversed with respect to each other.
bool HRTFElevation::calculateSymmetricKernelsForAzimuthElevation(int azimuth, int elevation, float sampleRate, const String& subjectName,
RefPtr<HRTFKernel>& kernelL, RefPtr<HRTFKernel>& kernelR)
{
RefPtr<HRTFKernel> kernelL1;
RefPtr<HRTFKernel> kernelR1;
bool success = calculateKernelsForAzimuthElevation(azimuth, elevation, sampleRate, subjectName, kernelL1, kernelR1);
if (!success)
return false;
// And symmetric version
int symmetricAzimuth = !azimuth ? 0 : 360 - azimuth;
RefPtr<HRTFKernel> kernelL2;
RefPtr<HRTFKernel> kernelR2;
success = calculateKernelsForAzimuthElevation(symmetricAzimuth, elevation, sampleRate, subjectName, kernelL2, kernelR2);
if (!success)
return false;
// Notice L/R reversal in symmetric version.
kernelL = HRTFKernel::createInterpolatedKernel(kernelL1.get(), kernelR2.get(), 0.5f);
kernelR = HRTFKernel::createInterpolatedKernel(kernelR1.get(), kernelL2.get(), 0.5f);
return true;
}
bool HRTFElevation::calculateKernelsForAzimuthElevation(int azimuth, int elevation, float sampleRate, const String& subjectName,
RefPtr<HRTFKernel>& kernelL, RefPtr<HRTFKernel>& kernelR)
{
// Valid values for azimuth are 0 -> 345 in 15 degree increments.
// Valid values for elevation are -45 -> +90 in 15 degree increments.
bool isAzimuthGood = azimuth >= 0 && azimuth <= 345 && (azimuth / 15) * 15 == azimuth;
ASSERT(isAzimuthGood);
if (!isAzimuthGood)
return false;
bool isElevationGood = elevation >= -45 && elevation <= 90 && (elevation / 15) * 15 == elevation;
ASSERT(isElevationGood);
if (!isElevationGood)
return false;
// Construct the resource name from the subject name, azimuth, and elevation, for example:
// "IRC_Composite_C_R0195_T015_P000"
// Note: the passed in subjectName is not a string passed in via JavaScript or the web.
// It's passed in as an internal ASCII identifier and is an implementation detail.
int positiveElevation = elevation < 0 ? elevation + 360 : elevation;
#ifdef USE_CONCATENATED_IMPULSE_RESPONSES
AudioBus* bus(getConcatenatedImpulseResponsesForSubject(subjectName));
if (!bus)
return false;
int elevationIndex = positiveElevation / AzimuthSpacing;
if (positiveElevation > 90)
elevationIndex -= AzimuthSpacing;
// The concatenated impulse response is a bus containing all
// the elevations per azimuth, for all azimuths by increasing
// order. So for a given azimuth and elevation we need to compute
// the index of the wanted audio frames in the concatenated table.
unsigned index = ((azimuth / AzimuthSpacing) * HRTFDatabase::NumberOfRawElevations) + elevationIndex;
bool isIndexGood = index < TotalNumberOfResponses;
ASSERT(isIndexGood);
if (!isIndexGood)
return false;
// Extract the individual impulse response from the concatenated
// responses and potentially sample-rate convert it to the desired
// (hardware) sample-rate.
unsigned startFrame = index * ResponseFrameSize;
unsigned stopFrame = startFrame + ResponseFrameSize;
auto preSampleRateConvertedResponse = AudioBus::createBufferFromRange(bus, startFrame, stopFrame);
auto response = AudioBus::createBySampleRateConverting(preSampleRateConvertedResponse.get(), false, sampleRate);
AudioChannel* leftEarImpulseResponse = response->channel(AudioBus::ChannelLeft);
AudioChannel* rightEarImpulseResponse = response->channel(AudioBus::ChannelRight);
#else
auto resourceName = makeString("IRC_", subjectName, "_C_R0195_T", pad('0', 3, azimuth), "_P", pad('0', 3, positiveElevation)).utf8();
RefPtr<AudioBus> impulseResponse(AudioBus::loadPlatformResource(resourceName.data(), sampleRate));
ASSERT(impulseResponse.get());
if (!impulseResponse.get())
return false;
size_t responseLength = impulseResponse->length();
size_t expectedLength = static_cast<size_t>(256 * (sampleRate / 44100.0));
// Check number of channels and length. For now these are fixed and known.
bool isBusGood = responseLength == expectedLength && impulseResponse->numberOfChannels() == 2;
ASSERT(isBusGood);
if (!isBusGood)
return false;
AudioChannel* leftEarImpulseResponse = impulseResponse->channelByType(AudioBus::ChannelLeft);
AudioChannel* rightEarImpulseResponse = impulseResponse->channelByType(AudioBus::ChannelRight);
#endif
// Note that depending on the fftSize returned by the panner, we may be truncating the impulse response we just loaded in.
const size_t fftSize = HRTFPanner::fftSizeForSampleRate(sampleRate);
kernelL = HRTFKernel::create(leftEarImpulseResponse, fftSize, sampleRate);
kernelR = HRTFKernel::create(rightEarImpulseResponse, fftSize, sampleRate);
return true;
}
// The range of elevations for the IRCAM impulse responses varies depending on azimuth, but the minimum elevation appears to always be -45.
//
// Here's how it goes:
static const int maxElevations[] = {
// Azimuth
//
90, // 0
45, // 15
60, // 30
45, // 45
75, // 60
45, // 75
60, // 90
45, // 105
75, // 120
45, // 135
60, // 150
45, // 165
75, // 180
45, // 195
60, // 210
45, // 225
75, // 240
45, // 255
60, // 270
45, // 285
75, // 300
45, // 315
60, // 330
45 // 345
};
std::unique_ptr<HRTFElevation> HRTFElevation::createForSubject(const String& subjectName, int elevation, float sampleRate)
{
bool isElevationGood = elevation >= -45 && elevation <= 90 && (elevation / 15) * 15 == elevation;
ASSERT(isElevationGood);
if (!isElevationGood)
return nullptr;
auto kernelListL = makeUnique<HRTFKernelList>(NumberOfTotalAzimuths);
auto kernelListR = makeUnique<HRTFKernelList>(NumberOfTotalAzimuths);
// Load convolution kernels from HRTF files.
int interpolatedIndex = 0;
for (unsigned rawIndex = 0; rawIndex < NumberOfRawAzimuths; ++rawIndex) {
// Don't let elevation exceed maximum for this azimuth.
int maxElevation = maxElevations[rawIndex];
int actualElevation = std::min(elevation, maxElevation);
bool success = calculateKernelsForAzimuthElevation(rawIndex * AzimuthSpacing, actualElevation, sampleRate, subjectName, kernelListL->at(interpolatedIndex), kernelListR->at(interpolatedIndex));
if (!success)
return nullptr;
interpolatedIndex += InterpolationFactor;
}
// Now go back and interpolate intermediate azimuth values.
for (unsigned i = 0; i < NumberOfTotalAzimuths; i += InterpolationFactor) {
int j = (i + InterpolationFactor) % NumberOfTotalAzimuths;
// Create the interpolated convolution kernels and delays.
for (unsigned jj = 1; jj < InterpolationFactor; ++jj) {
float x = float(jj) / float(InterpolationFactor); // interpolate from 0 -> 1
(*kernelListL)[i + jj] = HRTFKernel::createInterpolatedKernel(kernelListL->at(i).get(), kernelListL->at(j).get(), x);
(*kernelListR)[i + jj] = HRTFKernel::createInterpolatedKernel(kernelListR->at(i).get(), kernelListR->at(j).get(), x);
}
}
return makeUnique<HRTFElevation>(WTFMove(kernelListL), WTFMove(kernelListR), elevation, sampleRate);
}
std::unique_ptr<HRTFElevation> HRTFElevation::createByInterpolatingSlices(HRTFElevation* hrtfElevation1, HRTFElevation* hrtfElevation2, float x, float sampleRate)
{
ASSERT(hrtfElevation1 && hrtfElevation2);
if (!hrtfElevation1 || !hrtfElevation2)
return nullptr;
ASSERT(x >= 0.0 && x < 1.0);
auto kernelListL = makeUnique<HRTFKernelList>(NumberOfTotalAzimuths);
auto kernelListR = makeUnique<HRTFKernelList>(NumberOfTotalAzimuths);
HRTFKernelList* kernelListL1 = hrtfElevation1->kernelListL();
HRTFKernelList* kernelListR1 = hrtfElevation1->kernelListR();
HRTFKernelList* kernelListL2 = hrtfElevation2->kernelListL();
HRTFKernelList* kernelListR2 = hrtfElevation2->kernelListR();
// Interpolate kernels of corresponding azimuths of the two elevations.
for (unsigned i = 0; i < NumberOfTotalAzimuths; ++i) {
(*kernelListL)[i] = HRTFKernel::createInterpolatedKernel(kernelListL1->at(i).get(), kernelListL2->at(i).get(), x);
(*kernelListR)[i] = HRTFKernel::createInterpolatedKernel(kernelListR1->at(i).get(), kernelListR2->at(i).get(), x);
}
// Interpolate elevation angle.
double angle = (1.0 - x) * hrtfElevation1->elevationAngle() + x * hrtfElevation2->elevationAngle();
return makeUnique<HRTFElevation>(WTFMove(kernelListL), WTFMove(kernelListR), static_cast<int>(angle), sampleRate);
}
void HRTFElevation::getKernelsFromAzimuth(double azimuthBlend, unsigned azimuthIndex, HRTFKernel* &kernelL, HRTFKernel* &kernelR, double& frameDelayL, double& frameDelayR)
{
bool checkAzimuthBlend = azimuthBlend >= 0.0 && azimuthBlend < 1.0;
ASSERT(checkAzimuthBlend);
if (!checkAzimuthBlend)
azimuthBlend = 0.0;
unsigned numKernels = m_kernelListL->size();
bool isIndexGood = azimuthIndex < numKernels;
ASSERT(isIndexGood);
if (!isIndexGood) {
kernelL = 0;
kernelR = 0;
return;
}
// Return the left and right kernels.
kernelL = m_kernelListL->at(azimuthIndex).get();
kernelR = m_kernelListR->at(azimuthIndex).get();
frameDelayL = m_kernelListL->at(azimuthIndex)->frameDelay();
frameDelayR = m_kernelListR->at(azimuthIndex)->frameDelay();
int azimuthIndex2 = (azimuthIndex + 1) % numKernels;
double frameDelay2L = m_kernelListL->at(azimuthIndex2)->frameDelay();
double frameDelay2R = m_kernelListR->at(azimuthIndex2)->frameDelay();
// Linearly interpolate delays.
frameDelayL = (1.0 - azimuthBlend) * frameDelayL + azimuthBlend * frameDelay2L;
frameDelayR = (1.0 - azimuthBlend) * frameDelayR + azimuthBlend * frameDelay2R;
}
} // namespace WebCore
#endif // ENABLE(WEB_AUDIO)