| 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
|
| new file mode 100644
|
| index 0000000000000000000000000000000000000000..90bd15a307c1b8ea9fd632e3f53af730c77c2220
|
| --- /dev/null
|
| +++ b/third_party/WebKit/LayoutTests/webaudio/BiquadFilter/tail-time-highpass.html
|
| @@ -0,0 +1,116 @@
|
| +<!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>
|
|
|
Chromium Code Reviews
Issue 2862373002:
Compute tail time from Biquad coefficients (Closed)
