| <!doctype html> |
| <html> |
| <head> |
| <title>Test Biquad Tail-Time</title> |
| <script src="../../imported/w3c/web-platform-tests/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> |
