Modified: trunk/Source/WebCore/ChangeLog (88071 => 88072)
--- trunk/Source/WebCore/ChangeLog 2011-06-03 22:42:58 UTC (rev 88071)
+++ trunk/Source/WebCore/ChangeLog 2011-06-03 22:52:41 UTC (rev 88072)
@@ -1,3 +1,22 @@
+2011-06-03 Chris Rogers <[email protected]>
+
+ Reviewed by Kenneth Russell.
+
+ Biquad filter coefficient naming is incorrect
+ https://bugs.webkit.org/show_bug.cgi?id=62053
+
+ No new tests since audio API is not yet implemented.
+
+ * platform/audio/Biquad.cpp:
+ (WebCore::Biquad::Biquad):
+ (WebCore::Biquad::process):
+ (WebCore::Biquad::processFast):
+ (WebCore::Biquad::setLowpassParams):
+ (WebCore::Biquad::setHighpassParams):
+ (WebCore::Biquad::setLowShelfParams):
+ (WebCore::Biquad::setZeroPolePairs):
+ * platform/audio/Biquad.h:
+
2011-06-03 Adam Barth <[email protected]>
Reviewed by Eric Seidel.
Modified: trunk/Source/WebCore/platform/audio/Biquad.cpp (88071 => 88072)
--- trunk/Source/WebCore/platform/audio/Biquad.cpp 2011-06-03 22:42:58 UTC (rev 88071)
+++ trunk/Source/WebCore/platform/audio/Biquad.cpp 2011-06-03 22:52:41 UTC (rev 88072)
@@ -53,14 +53,12 @@
#endif
// Initialize as pass-thru (straight-wire, no filter effect)
- m_a0 = 1.0;
- m_a1 = 0.0;
- m_a2 = 0.0;
+ m_b0 = 1.0;
m_b1 = 0.0;
m_b2 = 0.0;
+ m_a1 = 0.0;
+ m_a2 = 0.0;
- m_g = 1.0;
-
reset(); // clear filter memory
}
@@ -78,19 +76,17 @@
double y1 = m_y1;
double y2 = m_y2;
- double a0 = m_a0;
- double a1 = m_a1;
- double a2 = m_a2;
+ double b0 = m_b0;
double b1 = m_b1;
double b2 = m_b2;
+ double a1 = m_a1;
+ double a2 = m_a2;
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;
+ float y = b0*x + b1*x1 + b2*x2 - a1*y1 - a2*y2;
- y *= m_g;
-
*destP++ = y;
// Update state variables
@@ -106,11 +102,11 @@
m_y1 = y1;
m_y2 = y2;
- m_a0 = a0;
- m_a1 = a1;
- m_a2 = a2;
+ m_b0 = b0;
m_b1 = b1;
m_b2 = b2;
+ m_a1 = a1;
+ m_a2 = a2;
#endif
}
@@ -120,13 +116,12 @@
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 filterCoefficients[5];
+ filterCoefficients[0] = m_b0;
+ filterCoefficients[1] = m_b1;
+ filterCoefficients[2] = m_b2;
+ filterCoefficients[3] = m_a1;
+ filterCoefficients[4] = m_a2;
double* inputP = m_inputBuffer.data();
double* outputP = m_outputBuffer.data();
@@ -145,7 +140,7 @@
for (int i = 0; i < framesThisTime; ++i)
input2P[i] = *sourceP++;
- processSliceFast(inputP, outputP, B, framesThisTime);
+ processSliceFast(inputP, outputP, filterCoefficients, framesThisTime);
// Copy output buffer to output (converts float -> double).
for (int i = 0; i < framesThisTime; ++i)
@@ -202,11 +197,11 @@
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;
+ m_b0 = 2.0 * alpha;
+ m_b1 = 2.0 * 2.0*alpha;
+ m_b2 = 2.0 * alpha;
+ m_a1 = 2.0 * -gamma;
+ m_a2 = 2.0 * beta;
}
void Biquad::setHighpassParams(double cutoff, double resonance)
@@ -223,11 +218,11 @@
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;
+ m_b0 = 2.0 * alpha;
+ m_b1 = 2.0 * -2.0*alpha;
+ m_b2 = 2.0 * alpha;
+ m_a1 = 2.0 * -gamma;
+ m_a2 = 2.0 * beta;
}
void Biquad::setLowShelfParams(double cutoff, double dbGain)
@@ -250,25 +245,25 @@
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;
+ m_b0 = b0 * a0Inverse;
+ m_b1 = b1 * a0Inverse;
+ m_b2 = b2 * a0Inverse;
+ m_a1 = a1 * a0Inverse;
+ m_a2 = a2 * a0Inverse;
}
void Biquad::setZeroPolePairs(const Complex &zero, const Complex &pole)
{
- m_a0 = 1.0;
- m_a1 = -2.0 * zero.real();
+ m_b0 = 1.0;
+ m_b1 = -2.0 * zero.real();
double zeroMag = abs(zero);
- m_a2 = zeroMag * zeroMag;
+ m_b2 = zeroMag * zeroMag;
- m_b1 = -2.0 * pole.real();
+ m_a1 = -2.0 * pole.real();
double poleMag = abs(pole);
- m_b2 = poleMag * poleMag;
+ m_a2 = poleMag * poleMag;
}
void Biquad::setAllpassPole(const Complex &pole)
Modified: trunk/Source/WebCore/platform/audio/Biquad.h (88071 => 88072)
--- trunk/Source/WebCore/platform/audio/Biquad.h 2011-06-03 22:42:58 UTC (rev 88071)
+++ trunk/Source/WebCore/platform/audio/Biquad.h 2011-06-03 22:52:41 UTC (rev 88072)
@@ -71,14 +71,12 @@
private:
// Filter coefficients
- double m_a0;
- double m_a1;
- double m_a2;
+ double m_b0;
double m_b1;
double m_b2;
+ double m_a1;
+ double m_a2;
- double m_g;
-
// Filter memory
double m_x1; // input delayed by 1 sample
double m_x2; // input delayed by 2 samples
