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1 // Copyright 2016 The Chromium Authors. All rights reserved. | 1 // Copyright 2016 The Chromium Authors. All rights reserved. |
2 // Use of this source code is governed by a BSD-style license that can be | 2 // Use of this source code is governed by a BSD-style license that can be |
3 // found in the LICENSE file. | 3 // found in the LICENSE file. |
4 | 4 |
5 #include "modules/webaudio/IIRDSPKernel.h" | 5 #include "modules/webaudio/IIRDSPKernel.h" |
6 | 6 |
7 #include "platform/FloatConversion.h" | 7 #include "wtf/MathExtras.h" |
8 | 8 |
9 namespace blink { | 9 namespace blink { |
10 | 10 |
11 void IIRDSPKernel::process(const float* source, float* destination, size_t frame
sToProcess) | 11 void IIRDSPKernel::process(const float* source, float* destination, size_t frame
sToProcess) |
12 { | 12 { |
13 DCHECK(source); | 13 DCHECK(source); |
14 DCHECK(destination); | 14 DCHECK(destination); |
15 | 15 |
16 m_iir.process(source, destination, framesToProcess); | 16 m_iir.process(source, destination, framesToProcess); |
17 } | 17 } |
18 | 18 |
19 void IIRDSPKernel::getFrequencyResponse(int nFrequencies, const float* frequency
Hz, float* magResponse, float* phaseResponse) | 19 void IIRDSPKernel::getFrequencyResponse(int nFrequencies, const float* frequency
Hz, float* magResponse, float* phaseResponse) |
20 { | 20 { |
21 bool isGood = nFrequencies > 0 && frequencyHz && magResponse && phaseRespons
e; | 21 bool isGood = nFrequencies > 0 && frequencyHz && magResponse && phaseRespons
e; |
22 DCHECK(isGood); | 22 DCHECK(isGood); |
23 if (!isGood) | 23 if (!isGood) |
24 return; | 24 return; |
25 | 25 |
26 Vector<float> frequency(nFrequencies); | 26 Vector<float> frequency(nFrequencies); |
27 | 27 |
28 double nyquist = this->nyquist(); | 28 double nyquist = this->nyquist(); |
29 | 29 |
30 // Convert from frequency in Hz to normalized frequency (0 -> 1), | 30 // Convert from frequency in Hz to normalized frequency (0 -> 1), |
31 // with 1 equal to the Nyquist frequency. | 31 // with 1 equal to the Nyquist frequency. |
32 for (int k = 0; k < nFrequencies; ++k) | 32 for (int k = 0; k < nFrequencies; ++k) |
33 frequency[k] = narrowPrecisionToFloat(frequencyHz[k] / nyquist); | 33 frequency[k] = clampTo<float>(frequencyHz[k] / nyquist); |
34 | 34 |
35 m_iir.getFrequencyResponse(nFrequencies, frequency.data(), magResponse, phas
eResponse); | 35 m_iir.getFrequencyResponse(nFrequencies, frequency.data(), magResponse, phas
eResponse); |
36 } | 36 } |
37 | 37 |
38 double IIRDSPKernel::tailTime() const | 38 double IIRDSPKernel::tailTime() const |
39 { | 39 { |
40 // TODO(rtoy): This is true mathematically (infinite impulse response), but
perhaps it should be | 40 // TODO(rtoy): This is true mathematically (infinite impulse response), but
perhaps it should be |
41 // limited to a smaller value, possibly based on the actual filter coefficie
nts. To do that, we | 41 // limited to a smaller value, possibly based on the actual filter coefficie
nts. To do that, we |
42 // would probably need to find the pole, r, with largest magnitude and selec
t some threshold, | 42 // would probably need to find the pole, r, with largest magnitude and selec
t some threshold, |
43 // eps, such that |r|^n < eps for all n >= N. N is then the tailTime for th
e filter. If the | 43 // eps, such that |r|^n < eps for all n >= N. N is then the tailTime for th
e filter. If the |
44 // the magnitude of r is greater than or equal to 1, the infinity is the rig
ht answer. (There is | 44 // the magnitude of r is greater than or equal to 1, the infinity is the rig
ht answer. (There is |
45 // no constraint on the IIR filter that it be stable.) | 45 // no constraint on the IIR filter that it be stable.) |
46 return std::numeric_limits<double>::infinity(); | 46 return std::numeric_limits<double>::infinity(); |
47 } | 47 } |
48 | 48 |
49 double IIRDSPKernel::latencyTime() const | 49 double IIRDSPKernel::latencyTime() const |
50 { | 50 { |
51 return 0; | 51 return 0; |
52 } | 52 } |
53 | 53 |
54 } // namespace blink | 54 } // namespace blink |
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