hrtf_elevation.cc | Explore in Territory

/*
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#ifdef UNSAFE_BUFFERS_BUILD
// TODO(crbug.com/351564777): Remove this and convert code to safer constructs.
#pragma allow_unsafe_buffers
#endif

#include "third_party/blink/renderer/platform/audio/hrtf_elevation.h"

#include <math.h>
#include <algorithm>
#include <memory>
#include <utility>

#include "base/memory/ptr_util.h"
#include "base/synchronization/lock.h"
#include "third_party/blink/renderer/platform/audio/audio_bus.h"
#include "third_party/blink/renderer/platform/audio/hrtf_database.h"
#include "third_party/blink/renderer/platform/audio/hrtf_panner.h"
#include "third_party/blink/renderer/platform/wtf/text/string_hash.h"

namespace blink {

namespace {
// Spacing, in degrees, between every azimuth loaded from resource.
constexpr unsigned kAzimuthSpacing = …;

// Number of azimuths loaded from resource.
constexpr unsigned kNumberOfRawAzimuths = …;

// Interpolates by this factor to get the total number of azimuths from every
// azimuth loaded from resource.
constexpr unsigned kInterpolationFactor = …;

// Total number of azimuths after interpolation.
constexpr unsigned kNumberOfTotalAzimuths = …;

// Total number of components of an HRTF database.
constexpr size_t kTotalNumberOfResponses = …;

// Number of frames in an individual impulse response.
constexpr size_t kResponseFrameSize = …;

// 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 kResponseSampleRate = …;

// This table maps the index into the elevation table with the corresponding
// angle. See https://bugs.webkit.org/show_bug.cgi?id=98294#c9 for the
// elevation angles and their order in the concatenated response.
constexpr int kElevationIndexTableSize = …;
constexpr int kElevationIndexTable[kElevationIndexTableSize] = …;

// 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:
constexpr int kMaxElevations[] = …;

// Lazily load a concatenated HRTF database for given subject and store it in a
// local hash table to ensure quick efficient future retrievals.
scoped_refptr<AudioBus> GetConcatenatedImpulseResponsesForSubject(
    int subject_resource_id) { … }

}  // namespace

bool HRTFElevation::CalculateKernelsForAzimuthElevation(
    int azimuth,
    int elevation,
    float sample_rate,
    int subject_resource_id,
    std::unique_ptr<HRTFKernel>& kernel_l,
    std::unique_ptr<HRTFKernel>& kernel_r) { … }

std::unique_ptr<HRTFElevation> HRTFElevation::CreateForSubject(
    int subject_resource_id,
    int elevation,
    float sample_rate) { … }

std::unique_ptr<HRTFElevation> HRTFElevation::CreateByInterpolatingSlices(
    HRTFElevation* hrtf_elevation1,
    HRTFElevation* hrtf_elevation2,
    float x) { … }

unsigned HRTFElevation::NumberOfAzimuths() { … }

void HRTFElevation::GetKernelsFromAzimuth(double azimuth_blend,
                                          unsigned azimuth_index,
                                          HRTFKernel*& kernel_l,
                                          HRTFKernel*& kernel_r,
                                          double& frame_delay_l,
                                          double& frame_delay_r) { … }

}  // namespace blink
chromium/third_party/blink/renderer/platform/audio/hrtf_elevation.cc
