/src/qt/qtwebkit/Source/WebCore/platform/audio/HRTFPanner.cpp
C++ | 316 lines | 205 code | 49 blank | 62 comment | 53 complexity | a7761fae3a4b043416078ee6e795acb9 MD5 | raw file
- /*
- * 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;
- const int UninitializedAzimuth = -1;
- const unsigned RenderingQuantum = 128;
- HRTFPanner::HRTFPanner(float sampleRate, HRTFDatabaseLoader* databaseLoader)
- : Panner(PanningModelHRTF)
- , m_databaseLoader(databaseLoader)
- , m_sampleRate(sampleRate)
- , m_crossfadeSelection(CrossfadeSelection1)
- , m_azimuthIndex1(UninitializedAzimuth)
- , m_elevation1(0)
- , m_azimuthIndex2(UninitializedAzimuth)
- , m_elevation2(0)
- , m_crossfadeX(0)
- , m_crossfadeIncr(0)
- , m_convolverL1(fftSizeForSampleRate(sampleRate))
- , m_convolverR1(fftSizeForSampleRate(sampleRate))
- , m_convolverL2(fftSizeForSampleRate(sampleRate))
- , m_convolverR2(fftSizeForSampleRate(sampleRate))
- , m_delayLineL(MaxDelayTimeSeconds, sampleRate)
- , m_delayLineR(MaxDelayTimeSeconds, sampleRate)
- , m_tempL1(RenderingQuantum)
- , m_tempR1(RenderingQuantum)
- , m_tempL2(RenderingQuantum)
- , m_tempR2(RenderingQuantum)
- {
- ASSERT(databaseLoader);
- }
- HRTFPanner::~HRTFPanner()
- {
- }
- size_t HRTFPanner::fftSizeForSampleRate(float 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 the FFT-size only for sample rates at least double this.
- ASSERT(sampleRate >= 44100 && sampleRate <= 96000.0);
- return (sampleRate < 88200.0) ? 512 : 1024;
- }
- void HRTFPanner::reset()
- {
- m_convolverL1.reset();
- m_convolverR1.reset();
- m_convolverL2.reset();
- m_convolverR2.reset();
- m_delayLineL.reset();
- m_delayLineR.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();
- 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 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 = m_databaseLoader->database();
- 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.
- const AudioChannel* inputChannelL = inputBus->channelByType(AudioBus::ChannelLeft);
- const AudioChannel* inputChannelR = numInputChannels > 1 ? inputBus->channelByType(AudioBus::ChannelRight) : 0;
- // Get source and destination pointers.
- const float* sourceL = inputChannelL->data();
- const float* sourceR = numInputChannels > 1 ? inputChannelR->data() : sourceL;
- float* destinationL = outputBus->channelByType(AudioBus::ChannelLeft)->mutableData();
- float* destinationR = outputBus->channelByType(AudioBus::ChannelRight)->mutableData();
- 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;
- }
- }
- // This algorithm currently requires that we process in power-of-two size chunks at least RenderingQuantum.
- ASSERT(1UL << static_cast<int>(log2(framesToProcess)) == framesToProcess);
- ASSERT(framesToProcess >= RenderingQuantum);
- const unsigned framesPerSegment = RenderingQuantum;
- const unsigned numberOfSegments = framesToProcess / framesPerSegment;
- for (unsigned segment = 0; segment < numberOfSegments; ++segment) {
- // 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;
- ASSERT(areKernelsGood);
- if (!areKernelsGood) {
- outputBus->zero();
- return;
- }
- ASSERT(frameDelayL1 / sampleRate() < MaxDelayTimeSeconds && frameDelayR1 / sampleRate() < MaxDelayTimeSeconds);
- ASSERT(frameDelayL2 / sampleRate() < MaxDelayTimeSeconds && frameDelayR2 / sampleRate() < MaxDelayTimeSeconds);
- // Crossfade inter-aural delays based on transitions.
- double frameDelayL = (1 - m_crossfadeX) * frameDelayL1 + m_crossfadeX * frameDelayL2;
- double frameDelayR = (1 - m_crossfadeX) * frameDelayR1 + m_crossfadeX * frameDelayR2;
- // Calculate the source and destination pointers for the current segment.
- unsigned offset = segment * framesPerSegment;
- const float* segmentSourceL = sourceL + offset;
- const 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);
- bool needsCrossfading = m_crossfadeIncr;
-
- // Have the convolvers render directly to the final destination if we're not cross-fading.
- float* convolutionDestinationL1 = needsCrossfading ? m_tempL1.data() : segmentDestinationL;
- float* convolutionDestinationR1 = needsCrossfading ? m_tempR1.data() : segmentDestinationR;
- float* convolutionDestinationL2 = needsCrossfading ? m_tempL2.data() : segmentDestinationL;
- float* convolutionDestinationR2 = needsCrossfading ? m_tempR2.data() : segmentDestinationR;
- // 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(), segmentDestinationL, convolutionDestinationL1, framesPerSegment);
- m_convolverR1.process(kernelR1->fftFrame(), segmentDestinationR, convolutionDestinationR1, framesPerSegment);
- }
- if (m_crossfadeSelection == CrossfadeSelection2 || needsCrossfading) {
- m_convolverL2.process(kernelL2->fftFrame(), segmentDestinationL, convolutionDestinationL2, framesPerSegment);
- m_convolverR2.process(kernelR2->fftFrame(), segmentDestinationR, convolutionDestinationR2, framesPerSegment);
- }
-
- if (needsCrossfading) {
- // Apply linear cross-fade.
- float x = m_crossfadeX;
- float incr = m_crossfadeIncr;
- for (unsigned i = 0; i < framesPerSegment; ++i) {
- segmentDestinationL[i] = (1 - x) * convolutionDestinationL1[i] + x * convolutionDestinationL2[i];
- segmentDestinationR[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;
- }
- }
- }
- }
- double HRTFPanner::tailTime() const
- {
- // 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, which is MaxDelayTimeSeconds
- // and fftSize() / 2, respectively.
- return MaxDelayTimeSeconds + (fftSize() / 2) / static_cast<double>(sampleRate());
- }
- double HRTFPanner::latencyTime() const
- {
- // The latency of a FFTConvolver is also fftSize() / 2, and is in addition to its tailTime of the
- // same value.
- return (fftSize() / 2) / static_cast<double>(sampleRate());
- }
- } // namespace WebCore
- #endif // ENABLE(WEB_AUDIO)