| /* |
| * Copyright (C) 2011 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. |
| * 3. Neither the name of Apple Computer, Inc. ("Apple") nor the names of |
| * its contributors may be used to endorse or promote products derived |
| * from this software without specific prior written permission. |
| * |
| * THIS SOFTWARE IS PROVIDED BY APPLE 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 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 "platform/audio/AudioBus.h" |
| #include "platform/audio/AudioUtilities.h" |
| #include "platform/audio/DynamicsCompressor.h" |
| #include "wtf/MathExtras.h" |
| #include "wtf/PtrUtil.h" |
| |
| namespace blink { |
| |
| using namespace AudioUtilities; |
| |
| DynamicsCompressor::DynamicsCompressor(float sampleRate, |
| unsigned numberOfChannels) |
| : m_numberOfChannels(numberOfChannels), |
| m_sampleRate(sampleRate), |
| m_compressor(sampleRate, numberOfChannels) { |
| // Uninitialized state - for parameter recalculation. |
| m_lastFilterStageRatio = -1; |
| m_lastAnchor = -1; |
| m_lastFilterStageGain = -1; |
| |
| setNumberOfChannels(numberOfChannels); |
| initializeParameters(); |
| } |
| |
| void DynamicsCompressor::setParameterValue(unsigned parameterID, float value) { |
| ASSERT(parameterID < ParamLast); |
| if (parameterID < ParamLast) |
| m_parameters[parameterID] = value; |
| } |
| |
| void DynamicsCompressor::initializeParameters() { |
| // Initializes compressor to default values. |
| |
| m_parameters[ParamThreshold] = -24; // dB |
| m_parameters[ParamKnee] = 30; // dB |
| m_parameters[ParamRatio] = 12; // unit-less |
| m_parameters[ParamAttack] = 0.003f; // seconds |
| m_parameters[ParamRelease] = 0.250f; // seconds |
| m_parameters[ParamPreDelay] = 0.006f; // seconds |
| |
| // Release zone values 0 -> 1. |
| m_parameters[ParamReleaseZone1] = 0.09f; |
| m_parameters[ParamReleaseZone2] = 0.16f; |
| m_parameters[ParamReleaseZone3] = 0.42f; |
| m_parameters[ParamReleaseZone4] = 0.98f; |
| |
| m_parameters[ParamFilterStageGain] = 4.4f; // dB |
| m_parameters[ParamFilterStageRatio] = 2; |
| m_parameters[ParamFilterAnchor] = 15000 / nyquist(); |
| |
| m_parameters[ParamPostGain] = 0; // dB |
| m_parameters[ParamReduction] = 0; // dB |
| |
| // Linear crossfade (0 -> 1). |
| m_parameters[ParamEffectBlend] = 1; |
| } |
| |
| float DynamicsCompressor::parameterValue(unsigned parameterID) { |
| ASSERT(parameterID < ParamLast); |
| return m_parameters[parameterID]; |
| } |
| |
| void DynamicsCompressor::process(const AudioBus* sourceBus, |
| AudioBus* destinationBus, |
| unsigned framesToProcess) { |
| // Though numberOfChannels is retrived from destinationBus, we still name it |
| // numberOfChannels instead of numberOfDestinationChannels. It's because we |
| // internally match sourceChannels's size to destinationBus by channel |
| // up/down mix. Thus we need numberOfChannels |
| // to do the loop work for both m_sourceChannels and m_destinationChannels. |
| |
| unsigned numberOfChannels = destinationBus->numberOfChannels(); |
| unsigned numberOfSourceChannels = sourceBus->numberOfChannels(); |
| |
| ASSERT(numberOfChannels == m_numberOfChannels && numberOfSourceChannels); |
| |
| if (numberOfChannels != m_numberOfChannels || !numberOfSourceChannels) { |
| destinationBus->zero(); |
| return; |
| } |
| |
| switch (numberOfChannels) { |
| case 2: // stereo |
| m_sourceChannels[0] = sourceBus->channel(0)->data(); |
| |
| if (numberOfSourceChannels > 1) |
| m_sourceChannels[1] = sourceBus->channel(1)->data(); |
| else |
| // Simply duplicate mono channel input data to right channel for stereo |
| // processing. |
| m_sourceChannels[1] = m_sourceChannels[0]; |
| |
| break; |
| default: |
| // FIXME : support other number of channels. |
| ASSERT_NOT_REACHED(); |
| destinationBus->zero(); |
| return; |
| } |
| |
| for (unsigned i = 0; i < numberOfChannels; ++i) |
| m_destinationChannels[i] = destinationBus->channel(i)->mutableData(); |
| |
| float filterStageGain = parameterValue(ParamFilterStageGain); |
| float filterStageRatio = parameterValue(ParamFilterStageRatio); |
| float anchor = parameterValue(ParamFilterAnchor); |
| |
| if (filterStageGain != m_lastFilterStageGain || |
| filterStageRatio != m_lastFilterStageRatio || anchor != m_lastAnchor) { |
| m_lastFilterStageGain = filterStageGain; |
| m_lastFilterStageRatio = filterStageRatio; |
| m_lastAnchor = anchor; |
| } |
| |
| float dbThreshold = parameterValue(ParamThreshold); |
| float dbKnee = parameterValue(ParamKnee); |
| float ratio = parameterValue(ParamRatio); |
| float attackTime = parameterValue(ParamAttack); |
| float releaseTime = parameterValue(ParamRelease); |
| float preDelayTime = parameterValue(ParamPreDelay); |
| |
| // This is effectively a master volume on the compressed signal |
| // (pre-blending). |
| float dbPostGain = parameterValue(ParamPostGain); |
| |
| // Linear blending value from dry to completely processed (0 -> 1) |
| // 0 means the signal is completely unprocessed. |
| // 1 mixes in only the compressed signal. |
| float effectBlend = parameterValue(ParamEffectBlend); |
| |
| float releaseZone1 = parameterValue(ParamReleaseZone1); |
| float releaseZone2 = parameterValue(ParamReleaseZone2); |
| float releaseZone3 = parameterValue(ParamReleaseZone3); |
| float releaseZone4 = parameterValue(ParamReleaseZone4); |
| |
| // Apply compression to the source signal. |
| m_compressor.process(m_sourceChannels.get(), m_destinationChannels.get(), |
| numberOfChannels, framesToProcess, |
| |
| dbThreshold, dbKnee, ratio, attackTime, releaseTime, |
| preDelayTime, dbPostGain, effectBlend, |
| |
| releaseZone1, releaseZone2, releaseZone3, releaseZone4); |
| |
| // Update the compression amount. |
| setParameterValue(ParamReduction, m_compressor.meteringGain()); |
| } |
| |
| void DynamicsCompressor::reset() { |
| m_lastFilterStageRatio = -1; // for recalc |
| m_lastAnchor = -1; |
| m_lastFilterStageGain = -1; |
| |
| m_compressor.reset(); |
| } |
| |
| void DynamicsCompressor::setNumberOfChannels(unsigned numberOfChannels) { |
| m_sourceChannels = wrapArrayUnique(new const float*[numberOfChannels]); |
| m_destinationChannels = wrapArrayUnique(new float*[numberOfChannels]); |
| |
| m_compressor.setNumberOfChannels(numberOfChannels); |
| m_numberOfChannels = numberOfChannels; |
| } |
| |
| } // namespace blink |