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-rw-r--r--WebCore/platform/audio/HRTFPanner.cpp229
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diff --git a/WebCore/platform/audio/HRTFPanner.cpp b/WebCore/platform/audio/HRTFPanner.cpp
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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
- * ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
- * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
- */
-
-#include "config.h"
-
-#if ENABLE(WEB_AUDIO)
-
-#include "HRTFPanner.h"
-
-#include "AudioBus.h"
-#include "FFTConvolver.h"
-#include "HRTFDatabase.h"
-#include "HRTFDatabaseLoader.h"
-#include <algorithm>
-#include <wtf/MathExtras.h>
-#include <wtf/RefPtr.h>
-
-using namespace std;
-
-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;
-
-HRTFPanner::HRTFPanner(double sampleRate)
- : Panner(PanningModelHRTF)
- , m_sampleRate(sampleRate)
- , m_isFirstRender(true)
- , m_azimuthIndex(0)
- , m_convolverL(fftSizeForSampleRate(sampleRate))
- , m_convolverR(fftSizeForSampleRate(sampleRate))
- , m_delayLineL(MaxDelayTimeSeconds, sampleRate)
- , m_delayLineR(MaxDelayTimeSeconds, sampleRate)
-{
-}
-
-HRTFPanner::~HRTFPanner()
-{
-}
-
-size_t HRTFPanner::fftSizeForSampleRate(double sampleRate)
-{
- // The HRTF impulse responses (loaded as audio resources) are 512 sample-frames @44.1KHz.
- // Currently, we truncate the impulse responses to half this size, but an FFT-size of twice impulse response size is needed (for convolution).
- // So for sample rates around 44.1KHz an FFT size of 512 is good. We double that size for higher sample rates.
- ASSERT(sampleRate >= 44100 && sampleRate <= 96000.0);
- return (sampleRate <= 48000.0) ? 512 : 1024;
-}
-
-void HRTFPanner::reset()
-{
- m_isFirstRender = true;
- m_convolverL.reset();
- m_convolverR.reset();
- m_delayLineL.reset();
- m_delayLineR.reset();
-}
-
-static bool wrapDistance(int i, int j, int length)
-{
- int directDistance = abs(i - j);
- int indirectDistance = length - directDistance;
-
- return indirectDistance < directDistance;
-}
-
-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 = HRTFDatabaseLoader::defaultHRTFDatabase();
- 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, AudioBus* inputBus, AudioBus* outputBus, size_t framesToProcess)
-{
- unsigned numInputChannels = inputBus ? inputBus->numberOfChannels() : 0;
-
- bool isInputGood = inputBus && numInputChannels >= 1 && numInputChannels <= 2;
- ASSERT(isInputGood);
-
- bool isOutputGood = outputBus && outputBus->numberOfChannels() == 2 && framesToProcess <= outputBus->length();
- ASSERT(isOutputGood);
-
- if (!isInputGood || !isOutputGood) {
- if (outputBus)
- outputBus->zero();
- return;
- }
-
- // This code only runs as long as the context is alive and after database has been loaded.
- HRTFDatabase* database = HRTFDatabaseLoader::defaultHRTFDatabase();
- ASSERT(database);
- if (!database) {
- outputBus->zero();
- 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;
- ASSERT(isAzimuthGood);
- if (!isAzimuthGood) {
- outputBus->zero();
- 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.
- AudioChannel* inputChannelL = inputBus->channelByType(AudioBus::ChannelLeft);
- AudioChannel* inputChannelR = numInputChannels > 1 ? inputBus->channelByType(AudioBus::ChannelRight) : 0;
-
- // Get source and destination pointers.
- float* sourceL = inputChannelL->data();
- float* sourceR = numInputChannels > 1 ? inputChannelR->data() : sourceL;
- float* destinationL = outputBus->channelByType(AudioBus::ChannelLeft)->data();
- float* destinationR = outputBus->channelByType(AudioBus::ChannelRight)->data();
-
- double azimuthBlend;
- int desiredAzimuthIndex = calculateDesiredAzimuthIndexAndBlend(azimuth, azimuthBlend);
-
- // This algorithm currently requires that we process in power-of-two size chunks at least 128.
- ASSERT(1UL << static_cast<int>(log2(framesToProcess)) == framesToProcess);
- ASSERT(framesToProcess >= 128);
-
- const unsigned framesPerSegment = 128;
- const unsigned numberOfSegments = framesToProcess / framesPerSegment;
-
- for (unsigned segment = 0; segment < numberOfSegments; ++segment) {
- if (m_isFirstRender) {
- // Snap exactly to desired position (first time and after reset()).
- m_azimuthIndex = desiredAzimuthIndex;
- m_isFirstRender = false;
- } else {
- // Each segment renders with an azimuth index closer by one to the desired azimuth index.
- // Because inter-aural time delay is mostly a factor of azimuth and the delay is where the clicks and graininess come from,
- // we don't bother smoothing the elevations.
- int numberOfAzimuths = database->numberOfAzimuths();
- bool wrap = wrapDistance(m_azimuthIndex, desiredAzimuthIndex, numberOfAzimuths);
- if (wrap) {
- if (m_azimuthIndex < desiredAzimuthIndex)
- m_azimuthIndex = (m_azimuthIndex - 1 + numberOfAzimuths) % numberOfAzimuths;
- else if (m_azimuthIndex > desiredAzimuthIndex)
- m_azimuthIndex = (m_azimuthIndex + 1) % numberOfAzimuths;
- } else {
- if (m_azimuthIndex < desiredAzimuthIndex)
- m_azimuthIndex = (m_azimuthIndex + 1) % numberOfAzimuths;
- else if (m_azimuthIndex > desiredAzimuthIndex)
- m_azimuthIndex = (m_azimuthIndex - 1 + numberOfAzimuths) % numberOfAzimuths;
- }
- }
-
- // Get the HRTFKernels and interpolated delays.
- HRTFKernel* kernelL;
- HRTFKernel* kernelR;
- double frameDelayL;
- double frameDelayR;
- database->getKernelsFromAzimuthElevation(azimuthBlend, m_azimuthIndex, elevation, kernelL, kernelR, frameDelayL, frameDelayR);
-
- ASSERT(kernelL && kernelR);
- if (!kernelL || !kernelR) {
- outputBus->zero();
- return;
- }
-
- ASSERT(frameDelayL / sampleRate() < MaxDelayTimeSeconds && frameDelayR / sampleRate() < MaxDelayTimeSeconds);
-
- // Calculate the source and destination pointers for the current segment.
- unsigned offset = segment * framesPerSegment;
- float* segmentSourceL = sourceL + offset;
- float* segmentSourceR = sourceR + offset;
- float* segmentDestinationL = destinationL + offset;
- float* segmentDestinationR = destinationR + offset;
-
- // First run through delay lines for inter-aural time difference.
- m_delayLineL.setDelayFrames(frameDelayL);
- m_delayLineR.setDelayFrames(frameDelayR);
- m_delayLineL.process(segmentSourceL, segmentDestinationL, framesPerSegment);
- m_delayLineR.process(segmentSourceR, segmentDestinationR, framesPerSegment);
-
- // Now do the convolutions in-place.
- m_convolverL.process(kernelL->fftFrame(), segmentDestinationL, segmentDestinationL, framesPerSegment);
- m_convolverR.process(kernelR->fftFrame(), segmentDestinationR, segmentDestinationR, framesPerSegment);
- }
-}
-
-} // namespace WebCore
-
-#endif // ENABLE(WEB_AUDIO)