| Index: third_party/WebKit/LayoutTests/webaudio/BiquadFilter/tail-time-allpass.html
|
| diff --git a/third_party/WebKit/LayoutTests/webaudio/BiquadFilter/tail-time-allpass.html b/third_party/WebKit/LayoutTests/webaudio/BiquadFilter/tail-time-allpass.html
|
| new file mode 100644
|
| index 0000000000000000000000000000000000000000..b902f42a8236fcc77b05748be8fd9f49ee62f863
|
| --- /dev/null
|
| +++ b/third_party/WebKit/LayoutTests/webaudio/BiquadFilter/tail-time-allpass.html
|
| @@ -0,0 +1,103 @@
|
| +<!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 an allpass filter:
|
| + // b0 = 1 - alpha
|
| + // b1 = -2*cos(w0)
|
| + // b2 = 1 + alpha
|
| + // a0 = 1 + alpha
|
| + // a1 = -2*cos(w0)
|
| + // a2 = 1 - alpha
|
| + //
|
| + // where alpha = sin(w0)/(2*Q) 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
|
| + //
|
| + // (2*Q*cos(w0) +/- sqrt(1-4*Q^2)*sin(w0))/(2*Q + sin(w0))
|
| + //
|
| + // Thus, if 1-4*Q^2 < 0, the poles are complex. For 1-4*Q^2 > 0, the
|
| + // poles are real and distinct. For 1-4*Q^2 = 0, there are two identical
|
| + // real poles.
|
| +
|
| + // Array of tests to run. |descripton| is the task description for
|
| + // audit.define. |parameters| is option for |testTailTime|.
|
| + let tests = [
|
| + {
|
| + description:
|
| + {label: 'allpass-complex-roots', description: 'complex roots'},
|
| + parameters: {
|
| + prefix: 'Complex roots',
|
| + // Choose a fairly large Q to make the tail long. Frequency is
|
| + // fairly arbitrary.
|
| + filterOptions: {type: 'allpass', Q: 200, frequency: sampleRate / 4},
|
| + // This filter the actual real tail frame is 2317, and the node
|
| + // computed frame is 2316.81. Thus, the tail output should be
|
| + // exactly 0.
|
| + threshold: 0
|
| + }
|
| + },
|
| + {
|
| + description: {
|
| + label: 'allpass-real-distinct-roots',
|
| + description: 'real distinct roots'
|
| + },
|
| + parameters: {
|
| + prefix: 'Distinct roots',
|
| + filterOptions: {
|
| + type: 'allpass',
|
| + Q: 0.001,
|
| + frequency: sampleRate / 8,
|
| + },
|
| + // With this particular filter, the real tail frame is 4822, but
|
| + // the node way overestimates it to be 7136. Thus, the actual
|
| + // tail frames won't be exactly zero.
|
| + threshold: 1 / 32768
|
| + }
|
| + },
|
| + {
|
| + description: {
|
| + label: 'allpass-repeated-roots',
|
| + description: 'repeated real root'
|
| + },
|
| + parameters: {
|
| + prefix: 'Repeated roots',
|
| + // 1-4*Q^2 = 0 iff Q = 1/2.
|
| + filterOptions: {type: 'allpass', Q: 0.5, frequency: sampleRate / 8},
|
| + // The node estimated tail time is 16.8 frames, but the actual is
|
| + // 106. Thus, the outupt should be exactly 0.
|
| + threshold: 0
|
| + }
|
| + }
|
| + ];
|
| +
|
| + // Define an appropriate task for each test.
|
| + tests.forEach(entry => {
|
| + audit.define(entry.description, (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)
