| /* |
| * Copyright 2016 The Chromium Authors. All rights reserved. |
| * Copyright (C) 2020, Apple 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 "IIRProcessor.h" |
| |
| #include "IIRDSPKernel.h" |
| |
| namespace WebCore { |
| |
| IIRProcessor::IIRProcessor(float sampleRate, unsigned numberOfChannels, const Vector<double>& feedforward, const Vector<double>& feedback, bool isFilterStable) |
| : AudioDSPKernelProcessor(sampleRate, numberOfChannels) |
| , m_feedforward(feedforward) |
| , m_feedback(feedback) |
| , m_isFilterStable(isFilterStable) |
| { |
| unsigned feedbackLength = feedback.size(); |
| unsigned feedforwardLength = feedforward.size(); |
| ASSERT(feedbackLength > 0); |
| ASSERT(feedforwardLength > 0); |
| |
| // Need to scale the feedback and feedforward coefficients appropriately. |
| // (It's up to the caller to ensure feedbackCoef[0] is not 0.) |
| ASSERT(!!feedback[0]); |
| |
| if (feedback[0] != 1) { |
| // The provided filter is: |
| // |
| // a[0]*y(n) + a[1]*y(n-1) + ... = b[0]*x(n) + b[1]*x(n-1) + ... |
| // |
| // We want the leading coefficient of y(n) to be 1: |
| // |
| // y(n) + a[1]/a[0]*y(n-1) + ... = b[0]/a[0]*x(n) + b[1]/a[0]*x(n-1) + ... |
| // |
| // Thus, the feedback and feedforward coefficients need to be scaled by 1/a[0]. |
| float scale = feedback[0]; |
| for (unsigned k = 1; k < feedbackLength; ++k) |
| m_feedback[k] /= scale; |
| |
| for (unsigned k = 0; k < feedforwardLength; ++k) |
| m_feedforward[k] /= scale; |
| |
| // The IIRFilter checks to make sure this coefficient is 1, so make it so. |
| m_feedback[0] = 1; |
| } |
| |
| m_responseKernel = makeUnique<IIRDSPKernel>(*this); |
| } |
| |
| IIRProcessor::~IIRProcessor() |
| { |
| if (isInitialized()) |
| uninitialize(); |
| } |
| |
| std::unique_ptr<AudioDSPKernel> IIRProcessor::createKernel() |
| { |
| return makeUnique<IIRDSPKernel>(*this); |
| } |
| |
| void IIRProcessor::process(const AudioBus* source, AudioBus* destination, size_t framesToProcess) |
| { |
| if (!isInitialized()) { |
| destination->zero(); |
| return; |
| } |
| |
| // For each channel of our input, process using the corresponding IIRDSPKernel |
| // into the output channel. |
| for (size_t i = 0; i < m_kernels.size(); ++i) |
| m_kernels[i]->process(source->channel(i)->data(), destination->channel(i)->mutableData(), framesToProcess); |
| } |
| |
| void IIRProcessor::getFrequencyResponse(unsigned length, const float* frequencyHz, float* magResponse, float* phaseResponse) |
| { |
| m_responseKernel->getFrequencyResponse(length, frequencyHz, magResponse, phaseResponse); |
| } |
| |
| } // namespace WebCore |
| |
| #endif // ENABLE(WEB_AUDIO) |