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#include "HRTFElevation.h"
#include <speex/speex_resampler.h>
#include "mozilla/PodOperations.h"
#include "AudioSampleFormat.h"
#include "IRC_Composite_C_R0195-incl.cpp"
using namespace mozilla;
namespace WebCore {
const int elevationSpacing = irc_composite_c_r0195_elevation_interval;
const int firstElevation = irc_composite_c_r0195_first_elevation;
const int numberOfElevations = std::size(irc_composite_c_r0195);
const unsigned HRTFElevation::NumberOfTotalAzimuths = 360 / 15 * 8;
const int rawSampleRate = irc_composite_c_r0195_sample_rate;
// Number of frames in an individual impulse response.
const size_t ResponseFrameSize = 256;
size_t HRTFElevation::sizeOfIncludingThis(
mozilla::MallocSizeOf aMallocSizeOf)
const {
size_t amount = aMallocSizeOf(
this);
amount += m_kernelListL.ShallowSizeOfExcludingThis(aMallocSizeOf);
for (size_t i = 0; i < m_kernelListL.Length(); i++) {
amount += m_kernelListL[i]->sizeOfIncludingThis(aMallocSizeOf);
}
return amount;
}
size_t HRTFElevation::fftSizeForSampleRate(
float sampleRate) {
// The IRCAM HRTF impulse responses were 512 sample-frames @44.1KHz,
// but these have been truncated to 256 samples.
// An FFT-size of twice impulse response size is used (for convolution).
// So for sample rates of 44.1KHz an FFT size of 512 is good.
// We double the FFT-size only for sample rates at least double this.
// If the FFT size is too large then the impulse response will be padded
// with zeros without the fade-out provided by HRTFKernel.
MOZ_ASSERT(sampleRate > 1.0 && sampleRate < 1048576.0);
// This is the size if we were to use all raw response samples.
unsigned resampledLength =
floorf(ResponseFrameSize * sampleRate / rawSampleRate);
// Keep things semi-sane, with max FFT size of 1024.
unsigned size = std::min(resampledLength, 1023U);
// Ensure a minimum of 2 * WEBAUDIO_BLOCK_SIZE (with the size++ below) for
// FFTConvolver and set the 8 least significant bits for rounding up to
// the next power of 2 below.
size |= 2 * WEBAUDIO_BLOCK_SIZE - 1;
// Round up to the next power of 2, making the FFT size no more than twice
// the impulse response length. This doubles size for values that are
// already powers of 2. This works by filling in alls bit to right of the
// most significant bit. The most significant bit is no greater than
// 1 << 9, and the least significant 8 bits were already set above, so
// there is at most one bit to add.
size |= (size >> 1);
size++;
MOZ_ASSERT((size & (size - 1)) == 0);
return size;
}
nsReturnRef<HRTFKernel> HRTFElevation::calculateKernelForAzimuthElevation(
int azimuth,
int elevation, SpeexResamplerState* resampler,
float sampleRate) {
int elevationIndex = (elevation - firstElevation) / elevationSpacing;
MOZ_ASSERT(elevationIndex >= 0 && elevationIndex <= numberOfElevations);
int numberOfAzimuths = irc_composite_c_r0195[elevationIndex].count;
int azimuthSpacing = 360 / numberOfAzimuths;
MOZ_ASSERT(numberOfAzimuths * azimuthSpacing == 360);
int azimuthIndex = azimuth / azimuthSpacing;
MOZ_ASSERT(azimuthIndex * azimuthSpacing == azimuth);
const int16_t(&impulse_response_data)[ResponseFrameSize] =
irc_composite_c_r0195[elevationIndex].azimuths[azimuthIndex];
float response[ResponseFrameSize];
ConvertAudioSamples(impulse_response_data, response, ResponseFrameSize);
float* resampledResponse;
// Note that depending on the fftSize returned by the panner, we may be
// truncating the impulse response.
const size_t resampledResponseLength = fftSizeForSampleRate(sampleRate) / 2;
AutoTArray<AudioDataValue, 2 * ResponseFrameSize> resampled;
if (sampleRate == rawSampleRate) {
resampledResponse = response;
MOZ_ASSERT(resampledResponseLength == ResponseFrameSize);
}
else {
resampled.SetLength(resampledResponseLength);
resampledResponse = resampled.Elements();
speex_resampler_skip_zeros(resampler);
// Feed the input buffer into the resampler.
spx_uint32_t in_len = ResponseFrameSize;
spx_uint32_t out_len = resampled.Length();
speex_resampler_process_float(resampler, 0, response, &in_len,
resampled.Elements(), &out_len);
if (out_len < resampled.Length()) {
// The input should have all been processed.
MOZ_ASSERT(in_len == ResponseFrameSize);
// Feed in zeros get the data remaining in the resampler.
spx_uint32_t out_index = out_len;
in_len = speex_resampler_get_input_latency(resampler);
out_len = resampled.Length() - out_index;
speex_resampler_process_float(resampler, 0, nullptr, &in_len,
resampled.Elements() + out_index, &out_len);
out_index += out_len;
// There may be some uninitialized samples remaining for very low
// sample rates.
PodZero(resampled.Elements() + out_index, resampled.Length() - out_index);
}
speex_resampler_reset_mem(resampler);
}
return HRTFKernel::create(resampledResponse, resampledResponseLength,
sampleRate);
}
// 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 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
};
nsReturnRef<HRTFElevation> HRTFElevation::createBuiltin(
int elevation,
float sampleRate) {
if (elevation < firstElevation ||
elevation > firstElevation + numberOfElevations * elevationSpacing ||
(elevation / elevationSpacing) * elevationSpacing != elevation)
return nsReturnRef<HRTFElevation>();
// Spacing, in degrees, between every azimuth loaded from resource.
// Some elevations do not have data for all these intervals.
// See maxElevations.
static const unsigned AzimuthSpacing = 15;
static const unsigned NumberOfRawAzimuths = 360 / AzimuthSpacing;
static_assert(AzimuthSpacing * NumberOfRawAzimuths == 360,
"Not a multiple");
static const unsigned InterpolationFactor =
NumberOfTotalAzimuths / NumberOfRawAzimuths;
static_assert(
NumberOfTotalAzimuths == NumberOfRawAzimuths * InterpolationFactor,
"Not a multiple");
HRTFKernelList kernelListL;
kernelListL.SetLength(NumberOfTotalAzimuths);
SpeexResamplerState* resampler =
sampleRate == rawSampleRate
? nullptr
: speex_resampler_init(1, rawSampleRate, sampleRate,
SPEEX_RESAMPLER_QUALITY_MIN, nullptr);
// 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);
kernelListL[interpolatedIndex] = calculateKernelForAzimuthElevation(
rawIndex * AzimuthSpacing, actualElevation, resampler, sampleRate);
interpolatedIndex += InterpolationFactor;
}
if (resampler) speex_resampler_destroy(resampler);
// 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[i], kernelListL[j], x);
}
}
return nsReturnRef<HRTFElevation>(
new HRTFElevation(std::move(kernelListL), elevation, sampleRate));
}
nsReturnRef<HRTFElevation> HRTFElevation::createByInterpolatingSlices(
HRTFElevation* hrtfElevation1, HRTFElevation* hrtfElevation2,
float x,
float sampleRate) {
MOZ_ASSERT(hrtfElevation1 && hrtfElevation2);
if (!hrtfElevation1 || !hrtfElevation2)
return nsReturnRef<HRTFElevation>();
MOZ_ASSERT(x >= 0.0 && x < 1.0);
HRTFKernelList kernelListL;
kernelListL.SetLength(NumberOfTotalAzimuths);
const HRTFKernelList& kernelListL1 = hrtfElevation1->kernelListL();
const HRTFKernelList& kernelListL2 = hrtfElevation2->kernelListL();
// Interpolate kernels of corresponding azimuths of the two elevations.
for (
unsigned i = 0; i < NumberOfTotalAzimuths; ++i) {
kernelListL[i] = HRTFKernel::createInterpolatedKernel(kernelListL1[i],
kernelListL2[i], x);
}
// Interpolate elevation angle.
double angle = (1.0 - x) * hrtfElevation1->elevationAngle() +
x * hrtfElevation2->elevationAngle();
return nsReturnRef<HRTFElevation>(
new HRTFElevation(
std::move(kernelListL),
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;
MOZ_ASSERT(checkAzimuthBlend);
if (!checkAzimuthBlend) azimuthBlend = 0.0;
unsigned numKernels = m_kernelListL.Length();
bool isIndexGood = azimuthIndex < numKernels;
MOZ_ASSERT(isIndexGood);
if (!isIndexGood) {
kernelL = 0;
kernelR = 0;
return;
}
// Return the left and right kernels,
// using symmetry to produce the right kernel.
kernelL = m_kernelListL[azimuthIndex];
int azimuthIndexR = (numKernels - azimuthIndex) % numKernels;
kernelR = m_kernelListL[azimuthIndexR];
frameDelayL = kernelL->frameDelay();
frameDelayR = kernelR->frameDelay();
int azimuthIndex2L = (azimuthIndex + 1) % numKernels;
double frameDelay2L = m_kernelListL[azimuthIndex2L]->frameDelay();
int azimuthIndex2R = (numKernels - azimuthIndex2L) % numKernels;
double frameDelay2R = m_kernelListL[azimuthIndex2R]->frameDelay();
// Linearly interpolate delays.
frameDelayL =
(1.0 - azimuthBlend) * frameDelayL + azimuthBlend * frameDelay2L;
frameDelayR =
(1.0 - azimuthBlend) * frameDelayR + azimuthBlend * frameDelay2R;
}
}
// namespace WebCore
