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Unified Diff: third_party/WebKit/LayoutTests/webaudio/BiquadFilter/tail-time-highpass.html

Issue 2919503002: Revert of Compute tail time from Biquad coefficients (Closed)
Patch Set: Created 3 years, 7 months ago
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Index: third_party/WebKit/LayoutTests/webaudio/BiquadFilter/tail-time-highpass.html
diff --git a/third_party/WebKit/LayoutTests/webaudio/BiquadFilter/tail-time-highpass.html b/third_party/WebKit/LayoutTests/webaudio/BiquadFilter/tail-time-highpass.html
deleted file mode 100644
index 90bd15a307c1b8ea9fd632e3f53af730c77c2220..0000000000000000000000000000000000000000
--- a/third_party/WebKit/LayoutTests/webaudio/BiquadFilter/tail-time-highpass.html
+++ /dev/null
@@ -1,116 +0,0 @@
-<!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;
-
- // For a highpass filter:
- // b0 = (1+cos(w0))/2
- // b1 = -(1+cos(w0))
- // b2 = (1+cos(w0))/2
- // a0 = 1 + alpha
- // a1 = -2*cos(w0)
- // a2 = 1 - alpha
- //
- // where alpha = sin(w0)/(2*10^(Q/20)) and w0 = 2*%pi*f0/Fs.
- //
- // Equivalently a1 = -2*cos(w0)/(1+alpha), a2 = (1-alpha)/(1+alpha). The
- // poles of this filter are at
- //
- // cos(w0)/(1+alpha) +/- sqrt(alpha^2-sin(w0)^2)/(1+alpha)
- //
- // But alpha^2-sin(w0)^2 = sin(w0)^2*(1/4/10^(Q/10) - 1). Thus the poles
- // are complex if 1/4/10^(Q/10) < 1; real distinct if 1/4/10^(Q/10) > 1;
- // and repeated if 1/4/10^(Q/10) = 1.
-
- // Array of tests to run. |descripton| is the task description for
- // audit.define. |parameters| is option for |testTailTime|.
- let tests = [
- {
- descripton:
- {label: 'hpf-complex-roots', description: 'complex roots'},
- parameters: {
- prefix: 'HPF complex roots',
- filterOptions: {type: 'highpass', Q: 40, frequency: sampleRate / 4},
- // Node computed tail frame is 2079.4, which matches the actual tail
- // frome so output should be exactly 0.
- threshold: 0
- }
- },
- {
- descripton: {
- label: 'hpf-real-distinct-roots',
- description: 'real distinct roots'
- },
- parameters: {
- prefix: 'HPF real distinct roots',
- filterOptions:
- {type: 'highpass', Q: -50, frequency: sampleRate / 8},
- // With these filter parameters, the real tail time is 408, but
- // the node overestimates it to be 2367. Thus, the actual tail
- // frames won't be exactly zero.
- threshold: 1 / 32768
- }
- },
- {
- descripton:
- {label: 'hpf-repeated-root', description: 'repeated real root'},
- parameters: {
- prefix: 'HPF repeated roots (approximately)',
- // For a repeated root, we need 1/4/10^(Q/10) = 1, or Q =
- // -10*log(4)/log(10). This isn't exactly representable as a float,
- // so the roots might not actually be repeated. In fact the roots
- // are complex at 6.40239e-5*exp(i*1.570596).
- filterOptions: {
- type: 'highpass',
- Q: -10 * Math.log10(4),
- frequency: sampleRate / 4
- },
- // Node computed tail frame is 2.9, which matches the actual tail
- // frome so output should be exactly 0.
- threshold: 0
- }
- },
- {
- descripton: {label: 'hpf-real-roots-2', description: 'complex roots'},
- parameters: {
- prefix: 'HPF repeated roots 2',
- // This tests an extreme case where approximate impulse response is
- // h(n) = C*r^(n-1) and C < 1/32768. Thus, the impulse response is
- // always less than the response threshold of 1/32768.
- filterOptions:
- {type: 'highpass', Q: -100, frequency: sampleRate / 4},
- // Node computed tail frame is 0, which matches the actual tail
- // frame so output should be exactly 0.
- 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>

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