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/*
* 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 "third_party/blink/renderer/platform/audio/audio_bus.h"
#include "third_party/blink/renderer/platform/audio/audio_utilities.h"
#include "third_party/blink/renderer/platform/audio/dynamics_compressor.h"
#include "third_party/blink/renderer/platform/wtf/math_extras.h"
namespace blink {
using namespace AudioUtilities;
DynamicsCompressor::DynamicsCompressor(float sample_rate,
unsigned number_of_channels)
: number_of_channels_(number_of_channels),
sample_rate_(sample_rate),
compressor_(sample_rate, number_of_channels) {
// Uninitialized state - for parameter recalculation.
last_filter_stage_ratio_ = -1;
last_anchor_ = -1;
last_filter_stage_gain_ = -1;
SetNumberOfChannels(number_of_channels);
InitializeParameters();
}
void DynamicsCompressor::SetParameterValue(unsigned parameter_id, float value) {
DCHECK_LT(parameter_id, static_cast<unsigned>(kParamLast));
if (parameter_id < kParamLast)
parameters_[parameter_id] = value;
}
void DynamicsCompressor::InitializeParameters() {
// Initializes compressor to default values.
parameters_[kParamThreshold] = -24; // dB
parameters_[kParamKnee] = 30; // dB
parameters_[kParamRatio] = 12; // unit-less
parameters_[kParamAttack] = 0.003f; // seconds
parameters_[kParamRelease] = 0.250f; // seconds
parameters_[kParamPreDelay] = 0.006f; // seconds
// Release zone values 0 -> 1.
parameters_[kParamReleaseZone1] = 0.09f;
parameters_[kParamReleaseZone2] = 0.16f;
parameters_[kParamReleaseZone3] = 0.42f;
parameters_[kParamReleaseZone4] = 0.98f;
parameters_[kParamFilterStageGain] = 4.4f; // dB
parameters_[kParamFilterStageRatio] = 2;
parameters_[kParamFilterAnchor] = 15000 / Nyquist();
parameters_[kParamPostGain] = 0; // dB
parameters_[kParamReduction] = 0; // dB
// Linear crossfade (0 -> 1).
parameters_[kParamEffectBlend] = 1;
}
float DynamicsCompressor::ParameterValue(unsigned parameter_id) {
DCHECK_LT(parameter_id, static_cast<unsigned>(kParamLast));
return parameters_[parameter_id];
}
void DynamicsCompressor::Process(const AudioBus* source_bus,
AudioBus* destination_bus,
unsigned frames_to_process) {
// 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 number_of_channels = destination_bus->NumberOfChannels();
unsigned number_of_source_channels = source_bus->NumberOfChannels();
DCHECK_EQ(number_of_channels, number_of_channels_);
DCHECK(number_of_source_channels);
if (number_of_channels != number_of_channels_ || !number_of_source_channels) {
destination_bus->Zero();
return;
}
switch (number_of_channels) {
case 2: // stereo
source_channels_[0] = source_bus->Channel(0)->Data();
if (number_of_source_channels > 1)
source_channels_[1] = source_bus->Channel(1)->Data();
else
// Simply duplicate mono channel input data to right channel for stereo
// processing.
source_channels_[1] = source_channels_[0];
break;
default:
// FIXME : support other number of channels.
NOTREACHED();
destination_bus->Zero();
return;
}
for (unsigned i = 0; i < number_of_channels; ++i)
destination_channels_[i] = destination_bus->Channel(i)->MutableData();
float filter_stage_gain = ParameterValue(kParamFilterStageGain);
float filter_stage_ratio = ParameterValue(kParamFilterStageRatio);
float anchor = ParameterValue(kParamFilterAnchor);
if (filter_stage_gain != last_filter_stage_gain_ ||
filter_stage_ratio != last_filter_stage_ratio_ ||
anchor != last_anchor_) {
last_filter_stage_gain_ = filter_stage_gain;
last_filter_stage_ratio_ = filter_stage_ratio;
last_anchor_ = anchor;
}
float db_threshold = ParameterValue(kParamThreshold);
float db_knee = ParameterValue(kParamKnee);
float ratio = ParameterValue(kParamRatio);
float attack_time = ParameterValue(kParamAttack);
float release_time = ParameterValue(kParamRelease);
float pre_delay_time = ParameterValue(kParamPreDelay);
// This is effectively a master volume on the compressed signal
// (pre-blending).
float db_post_gain = ParameterValue(kParamPostGain);
// 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 effect_blend = ParameterValue(kParamEffectBlend);
float release_zone1 = ParameterValue(kParamReleaseZone1);
float release_zone2 = ParameterValue(kParamReleaseZone2);
float release_zone3 = ParameterValue(kParamReleaseZone3);
float release_zone4 = ParameterValue(kParamReleaseZone4);
// Apply compression to the source signal.
compressor_.Process(source_channels_.get(), destination_channels_.get(),
number_of_channels, frames_to_process,
db_threshold, db_knee, ratio, attack_time, release_time,
pre_delay_time, db_post_gain, effect_blend,
release_zone1, release_zone2, release_zone3,
release_zone4);
// Update the compression amount.
SetParameterValue(kParamReduction, compressor_.MeteringGain());
}
void DynamicsCompressor::Reset() {
last_filter_stage_ratio_ = -1; // for recalc
last_anchor_ = -1;
last_filter_stage_gain_ = -1;
compressor_.Reset();
}
void DynamicsCompressor::SetNumberOfChannels(unsigned number_of_channels) {
source_channels_ = std::make_unique<const float* []>(number_of_channels);
destination_channels_ = std::make_unique<float* []>(number_of_channels);
compressor_.SetNumberOfChannels(number_of_channels);
number_of_channels_ = number_of_channels;
}
double DynamicsCompressor::TailTime() const {
return compressor_.TailTime();
}
} // namespace blink
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