| Index: third_party/WebKit/LayoutTests/webaudio/BiquadFilter/tail-time-lowshelf.html
|
| diff --git a/third_party/WebKit/LayoutTests/webaudio/BiquadFilter/tail-time-lowshelf.html b/third_party/WebKit/LayoutTests/webaudio/BiquadFilter/tail-time-lowshelf.html
|
| new file mode 100644
|
| index 0000000000000000000000000000000000000000..b8af1f33f2a940e8bfb89bf9c721f69de3f941b6
|
| --- /dev/null
|
| +++ b/third_party/WebKit/LayoutTests/webaudio/BiquadFilter/tail-time-lowshelf.html
|
| @@ -0,0 +1,83 @@
|
| +<!doctype html>
|
| +<html>
|
| + <head>
|
| + <title>Test Biquad Tail-Time</title>
|
| + <script src="../../resources/testharness.js"></script>
|
| + <script src="../../resources/testharnessreport.js"></script>
|
| + <script src="../resources/audit-util.js"></script>
|
| + <script src="../resources/audit.js"></script>
|
| + <script src="../resources/biquad-filters.js"></script>
|
| + <script src="test-tail-time.js"></script>
|
| + </head>
|
| +
|
| + <body>
|
| + <script>
|
| + let audit = Audit.createTaskRunner();
|
| +
|
| + let sampleRate = 16384;
|
| + let renderSeconds = 1;
|
| + let renderFrames = renderSeconds * sampleRate;
|
| + let renderQuantumFrames = 128;
|
| +
|
| + // For a lowshelf filter:
|
| + // b0 = A*[(A+1)−(A−1)*cos(w0)+2*as*sqrt(A)]
|
| + // b1 = 2*A*[(A+1)-(A-1)*cos(w0)]
|
| + // b2 = A*[(A+1)−(A−1)*cos(w0)-2*as*sqrt(A)]
|
| + // a0 = (A+1)+(A-1)*cos(w0)+2*as*sqrt(A)
|
| + // a1 = -2*[(A-1)+(A+1)*cos(w0)]
|
| + // a2 = (A+1)+(A-1)*cos(w0)-2*as*sqrt(A)
|
| + //
|
| + // where as = sin(w0)/sqrt(2), w0 = 2*%pi*f0/Fs, and A = 10^(G/40)
|
| + //
|
| + // The poles of this filter are
|
| + //
|
| + // -a2/(2*a0) +/- sqrt(a1^2-4*a0*a2)/(2*a0).
|
| + //
|
| + // Thus, the poles depend on the sign of d = a1^2-4*a0*a2 =
|
| + // 16*A*(as^2-sin(w0)^2) = -8*A*sin(w0)^2. Thus, the poles are always
|
| + // complex except if w0 = 0, in which case there is a repeated pole at 0.
|
| +
|
| + // Array of tests to run. |descripton| is the task description for
|
| + // audit.define. |parameters| is option for |testTailTime|.
|
| + let tests = [
|
| + {
|
| + descripton:
|
| + {label: 'lowshelf-complex-roots', description: 'complex roots'},
|
| + parameters: {
|
| + prefix: 'Lowshelf complex roots',
|
| + filterOptions:
|
| + {type: 'lowshelf', gain: 40, frequency: sampleRate / 8},
|
| + // Node computed tail frame is 75.5 frames, which matches the actual
|
| + // tail, so tail output should be exactly zero.
|
| + threshold: 0
|
| + },
|
| + },
|
| + {
|
| + descripton: {
|
| + label: 'lowshelf-repeated-roots',
|
| + description: 'repeated real root'
|
| + },
|
| + parameters: {
|
| + prefix: 'Lowshelf repeated roots',
|
| + filterOptions:
|
| + {type: 'lowshelf', Q: 1 / 20, gain: 40, frequency: 0},
|
| + // Node computed tail frame is 2 frames, which matches the actual
|
| + // tail, so tail output should be exactly zero.
|
| + threshold: 0
|
| + },
|
| + },
|
| + ];
|
| +
|
| + // Define an appropriate task for each test.
|
| + tests.forEach(entry => {
|
| + audit.define(entry.descripton, (task, should) => {
|
| + let context = new OfflineAudioContext(1, renderFrames, sampleRate);
|
| + testTailTime(should, context, entry.parameters)
|
| + .then(() => task.done());
|
| + });
|
| + });
|
| +
|
| + audit.run();
|
| + </script>
|
| + </body>
|
| +</html>
|
|
|
Chromium Code Reviews
Issue 2862373002:
Compute tail time from Biquad coefficients (Closed)
