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-rw-r--r--WebCore/platform/audio/Biquad.cpp282
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diff --git a/WebCore/platform/audio/Biquad.cpp b/WebCore/platform/audio/Biquad.cpp
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--- a/WebCore/platform/audio/Biquad.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.
- * 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 "config.h"
-
-#if ENABLE(WEB_AUDIO)
-
-#include "Biquad.h"
-
-#include <algorithm>
-#include <stdio.h>
-#include <wtf/MathExtras.h>
-
-#if OS(DARWIN)
-#include <Accelerate/Accelerate.h>
-#endif
-
-namespace WebCore {
-
-const int kBufferSize = 1024;
-
-Biquad::Biquad()
-{
-#if OS(DARWIN)
- // Allocate two samples more for filter history
- m_inputBuffer.resize(kBufferSize + 2);
- m_outputBuffer.resize(kBufferSize + 2);
-#endif
-
- // Initialize as pass-thru (straight-wire, no filter effect)
- m_a0 = 1.0;
- m_a1 = 0.0;
- m_a2 = 0.0;
- m_b1 = 0.0;
- m_b2 = 0.0;
-
- m_g = 1.0;
-
- reset(); // clear filter memory
-}
-
-void Biquad::process(const float* sourceP, float* destP, size_t framesToProcess)
-{
-#if OS(DARWIN)
- // Use vecLib if available
- processFast(sourceP, destP, framesToProcess);
-#else
- int n = framesToProcess;
-
- // Create local copies of member variables
- double x1 = m_x1;
- double x2 = m_x2;
- double y1 = m_y1;
- double y2 = m_y2;
-
- double a0 = m_a0;
- double a1 = m_a1;
- double a2 = m_a2;
- double b1 = m_b1;
- double b2 = m_b2;
-
- while (n--) {
- // FIXME: this can be optimized by pipelining the multiply adds...
- float x = *sourceP++;
- float y = a0*x + a1*x1 + a2*x2 - b1*y1 - b2*y2;
-
- y *= m_g;
-
- *destP++ = y;
-
- // Update state variables
- x2 = x1;
- x1 = x;
- y2 = y1;
- y1 = y;
- }
-
- // Local variables back to member
- m_x1 = x1;
- m_x2 = x2;
- m_y1 = y1;
- m_y2 = y2;
-
- m_a0 = a0;
- m_a1 = a1;
- m_a2 = a2;
- m_b1 = b1;
- m_b2 = b2;
-#endif
-}
-
-#if OS(DARWIN)
-
-// Here we have optimized version using Accelerate.framework
-
-void Biquad::processFast(const float* sourceP, float* destP, size_t framesToProcess)
-{
- // Filter coefficients
- double B[5];
- B[0] = m_a0;
- B[1] = m_a1;
- B[2] = m_a2;
- B[3] = m_b1;
- B[4] = m_b2;
-
- double* inputP = m_inputBuffer.data();
- double* outputP = m_outputBuffer.data();
-
- double* input2P = inputP + 2;
- double* output2P = outputP + 2;
-
- // Break up processing into smaller slices (kBufferSize) if necessary.
-
- int n = framesToProcess;
-
- while (n > 0) {
- int framesThisTime = n < kBufferSize ? n : kBufferSize;
-
- // Copy input to input buffer
- for (int i = 0; i < framesThisTime; ++i)
- input2P[i] = *sourceP++;
-
- processSliceFast(inputP, outputP, B, framesThisTime);
-
- // Copy output buffer to output (converts float -> double).
- for (int i = 0; i < framesThisTime; ++i)
- *destP++ = static_cast<float>(output2P[i]);
-
- n -= framesThisTime;
- }
-}
-
-void Biquad::processSliceFast(double* sourceP, double* destP, double* coefficientsP, size_t framesToProcess)
-{
- // Use double-precision for filter stability
- vDSP_deq22D(sourceP, 1, coefficientsP, destP, 1, framesToProcess);
-
- // Save history. Note that sourceP and destP reference m_inputBuffer and m_outputBuffer respectively.
- // These buffers are allocated (in the constructor) with space for two extra samples so it's OK to access
- // array values two beyond framesToProcess.
- sourceP[0] = sourceP[framesToProcess - 2 + 2];
- sourceP[1] = sourceP[framesToProcess - 1 + 2];
- destP[0] = destP[framesToProcess - 2 + 2];
- destP[1] = destP[framesToProcess - 1 + 2];
-}
-
-#endif // OS(DARWIN)
-
-
-void Biquad::reset()
-{
- m_x1 = m_x2 = m_y1 = m_y2 = 0.0;
-
-#if OS(DARWIN)
- // Two extra samples for filter history
- double* inputP = m_inputBuffer.data();
- inputP[0] = 0.0;
- inputP[1] = 0.0;
-
- double* outputP = m_outputBuffer.data();
- outputP[0] = 0.0;
- outputP[1] = 0.0;
-#endif
-}
-
-void Biquad::setLowpassParams(double cutoff, double resonance)
-{
- resonance = std::max(0.0, resonance); // can't go negative
-
- double g = pow(10.0, 0.05 * resonance);
- double d = sqrt((4.0 - sqrt(16.0 - 16.0 / (g * g))) / 2.0);
-
- // Compute biquad coefficients for lopass filter
- double theta = piDouble * cutoff;
- double sn = 0.5 * d * sin(theta);
- double beta = 0.5 * (1.0 - sn) / (1.0 + sn);
- double gamma = (0.5 + beta) * cos(theta);
- double alpha = 0.25 * (0.5 + beta - gamma);
-
- m_a0 = 2.0 * alpha;
- m_a1 = 2.0 * 2.0*alpha;
- m_a2 = 2.0 * alpha;
- m_b1 = 2.0 * -gamma;
- m_b2 = 2.0 * beta;
-}
-
-void Biquad::setHighpassParams(double cutoff, double resonance)
-{
- resonance = std::max(0.0, resonance); // can't go negative
-
- double g = pow(10.0, 0.05 * resonance);
- double d = sqrt((4.0 - sqrt(16.0 - 16.0 / (g * g))) / 2.0);
-
- // Compute biquad coefficients for highpass filter
- double theta = piDouble * cutoff;
- double sn = 0.5 * d * sin(theta);
- double beta = 0.5 * (1.0 - sn) / (1.0 + sn);
- double gamma = (0.5 + beta) * cos(theta);
- double alpha = 0.25 * (0.5 + beta + gamma);
-
- m_a0 = 2.0 * alpha;
- m_a1 = 2.0 * -2.0*alpha;
- m_a2 = 2.0 * alpha;
- m_b1 = 2.0 * -gamma;
- m_b2 = 2.0 * beta;
-}
-
-void Biquad::setLowShelfParams(double cutoff, double dbGain)
-{
- double theta = piDouble * cutoff;
-
- double A = pow(10.0, dbGain / 40.0);
- double S = 1.0; // filter slope (1.0 is max value)
- double alpha = 0.5 * sin(theta) * sqrt((A + 1.0 / A) * (1.0 / S - 1.0) + 2.0);
-
- double k = cos(theta);
- double k2 = 2.0 * sqrt(A) * alpha;
-
- double b0 = A * ((A + 1.0) - (A - 1.0) * k + k2);
- double b1 = 2.0 * A * ((A - 1.0) - (A + 1.0) * k);
- double b2 = A * ((A + 1.0) - (A - 1.0) * k - k2);
- double a0 = (A + 1.0) + (A - 1.0) * k + k2;
- double a1 = -2.0 * ((A - 1.0) + (A + 1.0) * k);
- double a2 = (A + 1.0) + (A - 1.0) * k - k2;
-
- double a0Inverse = 1.0 / a0;
-
- m_a0 = b0 * a0Inverse;
- m_a1 = b1 * a0Inverse;
- m_a2 = b2 * a0Inverse;
- m_b1 = a1 * a0Inverse;
- m_b2 = a2 * a0Inverse;
-}
-
-void Biquad::setZeroPolePairs(const Complex &zero, const Complex &pole)
-{
- m_a0 = 1.0;
- m_a1 = -2.0 * zero.real();
-
- double zeroMag = abs(zero);
- m_a2 = zeroMag * zeroMag;
-
- m_b1 = -2.0 * pole.real();
-
- double poleMag = abs(pole);
- m_b2 = poleMag * poleMag;
-}
-
-void Biquad::setAllpassPole(const Complex &pole)
-{
- Complex zero = Complex(1.0, 0.0) / pole;
- setZeroPolePairs(zero, pole);
-}
-
-} // namespace WebCore
-
-#endif // ENABLE(WEB_AUDIO)
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