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Unified Diff: third_party/WebKit/Source/platform/audio/IIRFilter.cpp

Issue 2384073002: reflow comments in platform/audio (Closed)
Patch Set: comments (heh!) Created 4 years, 2 months ago
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Index: third_party/WebKit/Source/platform/audio/IIRFilter.cpp
diff --git a/third_party/WebKit/Source/platform/audio/IIRFilter.cpp b/third_party/WebKit/Source/platform/audio/IIRFilter.cpp
index 7b0b87af706b96e0d5ac2a6ce1e487d8f8c29787..5a4a49c96e98f7f955191f999f7504a87b567cf6 100644
--- a/third_party/WebKit/Source/platform/audio/IIRFilter.cpp
+++ b/third_party/WebKit/Source/platform/audio/IIRFilter.cpp
@@ -9,8 +9,8 @@
namespace blink {
-// The length of the memory buffers for the IIR filter. This MUST be a power of two and must be
-// greater than the possible length of the filter coefficients.
+// The length of the memory buffers for the IIR filter. This MUST be a power of
+// two and must be greater than the possible length of the filter coefficients.
const int kBufferLength = 32;
static_assert(kBufferLength >= IIRFilter::kMaxOrder + 1,
"Internal IIR buffer length must be greater than maximum IIR "
@@ -34,7 +34,8 @@ void IIRFilter::reset() {
static std::complex<double> evaluatePolynomial(const double* coef,
std::complex<double> z,
int order) {
- // Use Horner's method to evaluate the polynomial P(z) = sum(coef[k]*z^k, k, 0, order);
+ // Use Horner's method to evaluate the polynomial P(z) = sum(coef[k]*z^k, k,
+ // 0, order);
std::complex<double> result = 0;
for (int k = order; k >= 0; --k)
@@ -50,19 +51,20 @@ void IIRFilter::process(const float* sourceP,
//
// y[n] = sum(b[k] * x[n - k], k = 0, M) - sum(a[k] * y[n - k], k = 1, N)
//
- // where b[k] are the feedforward coefficients and a[k] are the feedback coefficients of the
- // filter.
+ // where b[k] are the feedforward coefficients and a[k] are the feedback
+ // coefficients of the filter.
- // This is a Direct Form I implementation of an IIR Filter. Should we consider doing a
- // different implementation such as Transposed Direct Form II?
+ // This is a Direct Form I implementation of an IIR Filter. Should we
+ // consider doing a different implementation such as Transposed Direct Form
+ // II?
const double* feedback = m_feedback->data();
const double* feedforward = m_feedforward->data();
ASSERT(feedback);
ASSERT(feedforward);
- // Sanity check to see if the feedback coefficients have been scaled appropriately. It must
- // be EXACTLY 1!
+ // Sanity check to see if the feedback coefficients have been scaled
+ // appropriately. It must be EXACTLY 1!
ASSERT(feedback[0] == 1);
int feedbackLength = m_feedback->size();
@@ -73,8 +75,8 @@ void IIRFilter::process(const float* sourceP,
double* yBuffer = m_yBuffer.data();
for (size_t n = 0; n < framesToProcess; ++n) {
- // To help minimize roundoff, we compute using double's, even though the filter coefficients
- // only have single precision values.
+ // To help minimize roundoff, we compute using double's, even though the
+ // filter coefficients only have single precision values.
double yn = feedforward[0] * sourceP[n];
// Run both the feedforward and feedback terms together, when possible.
@@ -91,7 +93,8 @@ void IIRFilter::process(const float* sourceP,
for (int k = minLength; k < feedbackLength; ++k)
yn -= feedback[k] * yBuffer[(m_bufferIndex - k) & (kBufferLength - 1)];
- // Save the current input and output values in the memory buffers for the next output.
+ // Save the current input and output values in the memory buffers for the
+ // next output.
m_xBuffer[m_bufferIndex] = sourceP[n];
m_yBuffer[m_bufferIndex] = yn;
@@ -105,17 +108,19 @@ void IIRFilter::getFrequencyResponse(int nFrequencies,
const float* frequency,
float* magResponse,
float* phaseResponse) {
- // Evaluate the z-transform of the filter at the given normalized frequencies from 0 to 1. (One
- // corresponds to the Nyquist frequency.)
+ // Evaluate the z-transform of the filter at the given normalized frequencies
+ // from 0 to 1. (One corresponds to the Nyquist frequency.)
//
// The z-tranform of the filter is
//
// H(z) = sum(b[k]*z^(-k), k, 0, M) / sum(a[k]*z^(-k), k, 0, N);
//
- // The desired frequency response is H(exp(j*omega)), where omega is in [0, 1).
+ // The desired frequency response is H(exp(j*omega)), where omega is in [0,
+ // 1).
//
- // Let P(x) = sum(c[k]*x^k, k, 0, P) be a polynomial of order P. Then each of the sums in H(z)
- // is equivalent to evaluating a polynomial at the point 1/z.
+ // Let P(x) = sum(c[k]*x^k, k, 0, P) be a polynomial of order P. Then each of
+ // the sums in H(z) is equivalent to evaluating a polynomial at the point
+ // 1/z.
for (int k = 0; k < nFrequencies; ++k) {
// zRecip = 1/z = exp(-j*frequency)
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