| Index: third_party/WebKit/LayoutTests/webaudio/iirfilter-getFrequencyResponse.html
|
| diff --git a/third_party/WebKit/LayoutTests/webaudio/iirfilter-getFrequencyResponse.html b/third_party/WebKit/LayoutTests/webaudio/iirfilter-getFrequencyResponse.html
|
| new file mode 100644
|
| index 0000000000000000000000000000000000000000..3192712ab935f1a666703ba92d2a1b4daae4a6cc
|
| --- /dev/null
|
| +++ b/third_party/WebKit/LayoutTests/webaudio/iirfilter-getFrequencyResponse.html
|
| @@ -0,0 +1,132 @@
|
| +<!doctype html>
|
| +<html>
|
| + <head>
|
| + <title>Test IIRFilter getFrequencyResponse() functionality</title>
|
| + <script src="../resources/js-test.js"></script>
|
| + <script src="resources/compatibility.js"></script>
|
| + <script src="resources/audio-testing.js"></script>
|
| + <script src="resources/biquad-filters.js"></script>
|
| + </head>
|
| +
|
| + <body>
|
| + <script>
|
| + description("Test IIRFilter getFrequencyResponse() functionality");
|
| + window.jsTestIsAsync = true;
|
| +
|
| + var sampleRate = 48000;
|
| + // Some short duration; we're not actually looking at the rendered output.
|
| + var testDurationSec = 0.01;
|
| +
|
| + // Number of frequency samples to take.
|
| + var numberOfFrequencies = 1000;
|
| +
|
| + var audit = Audit.createTaskRunner();
|
| +
|
| +
|
| + // Compute a set of linearly spaced frequencies.
|
| + function createFrequencies(nFrequencies, sampleRate)
|
| + {
|
| + var frequencies = new Float32Array(nFrequencies);
|
| + var nyquist = sampleRate / 2;
|
| + var freqDelta = nyquist / nFrequencies;
|
| +
|
| + for (var k = 0; k < nFrequencies; ++k) {
|
| + frequencies[k] = k * freqDelta;
|
| + }
|
| +
|
| + return frequencies;
|
| + }
|
| +
|
| + audit.defineTask("1-pole IIR", function (done) {
|
| + var context = new OfflineAudioContext(1, testDurationSec * sampleRate, sampleRate);
|
| +
|
| + var iir = context.createIIRFilter([1], [1, -0.9]);
|
| + var frequencies = createFrequencies(numberOfFrequencies, context.sampleRate);
|
| +
|
| + var iirMag = new Float32Array(numberOfFrequencies);
|
| + var iirPhase = new Float32Array(numberOfFrequencies);
|
| + var trueMag = new Float32Array(numberOfFrequencies);
|
| + var truePhase = new Float32Array(numberOfFrequencies);
|
| +
|
| + // The IIR filter is
|
| + // H(z) = 1/(1 - 0.9*z^(-1)).
|
| + //
|
| + // The frequency response is
|
| + // H(exp(j*w)) = 1/(1 - 0.9*exp(-j*w)).
|
| + //
|
| + // Thus, the magnitude is
|
| + // |H(exp(j*w))| = 1/sqrt(1.81-1.8*cos(w)).
|
| + //
|
| + // The phase is
|
| + // arg(H(exp(j*w)) = atan(0.9*sin(w)/(.9*cos(w)-1))
|
| +
|
| + var frequencyScale = Math.PI / (sampleRate / 2);
|
| +
|
| + for (var k = 0; k < frequencies.length; ++k) {
|
| + var omega = frequencyScale * frequencies[k];
|
| + trueMag[k] = 1/Math.sqrt(1.81-1.8*Math.cos(omega));
|
| + truePhase[k] = Math.atan(0.9 * Math.sin(omega) / (0.9 * Math.cos(omega) - 1));
|
| + }
|
| +
|
| + iir.getFrequencyResponse(frequencies, iirMag, iirPhase);
|
| +
|
| + var success = true;
|
| +
|
| + // Thresholds were experimentally determined.
|
| + success = Should("1-pole IIR Magnitude Response", iirMag).beCloseToArray(trueMag, 2.8611e-6);
|
| + success = Should("1-pole IIR Phase Response", iirPhase).beCloseToArray(truePhase, 1.7882e-7)
|
| + && success;
|
| + if (success)
|
| + testPassed("1-pole IIR response matched expected response.\n");
|
| + else
|
| + testFailed("1-pole IIR response did not match expected response.\n");
|
| +
|
| + done();
|
| + });
|
| +
|
| + audit.defineTask("compare IIR and biquad", function(done) {
|
| + // Create an IIR filter equivalent to the biquad filter. Compute the frequency response for
|
| + // both and verify that they are the same.
|
| + var context = new OfflineAudioContext(1, testDurationSec * sampleRate, sampleRate);
|
| +
|
| + var biquad = context.createBiquadFilter();
|
| + var coef = createFilter(biquad.type,
|
| + biquad.frequency.value / (context.sampleRate / 2),
|
| + biquad.Q.value,
|
| + biquad.gain.value);
|
| +
|
| + var iir = context.createIIRFilter([coef.b0, coef.b1, coef.b2], [1, coef.a1, coef.a2]);
|
| +
|
| + var frequencies = createFrequencies(numberOfFrequencies, context.sampleRate);
|
| + var biquadMag = new Float32Array(numberOfFrequencies);
|
| + var biquadPhase = new Float32Array(numberOfFrequencies);
|
| + var iirMag = new Float32Array(numberOfFrequencies);
|
| + var iirPhase = new Float32Array(numberOfFrequencies);
|
| +
|
| + biquad.getFrequencyResponse(frequencies, biquadMag, biquadPhase);
|
| + iir.getFrequencyResponse(frequencies, iirMag, iirPhase);
|
| +
|
| + var success = true;
|
| +
|
| + // Thresholds were experimentally determined.
|
| + success = Should("IIR Magnitude Response", iirMag).beCloseToArray(biquadMag, 2.7419e-5);
|
| + success = Should("IIR Phase Response", iirPhase).beCloseToArray(biquadPhase, 2.7657e-5) && success;
|
| +
|
| + if (success)
|
| + testPassed("IIR response matched equivalent " + biquad.type + " Biquad response.\n");
|
| + else
|
| + testFailed("IIR response did not equivalent " + biquad.type + " Biquad response.\n");
|
| +
|
| + done();
|
| + });
|
| +
|
| + audit.defineTask("finish", function (done) {
|
| + finishJSTest();
|
| + done();
|
| + });
|
| +
|
| + audit.runTasks();
|
| + successfullyParsed = true;
|
| + </script>
|
| + </body>
|
| +</html>
|
|
|
Chromium Code Reviews
Issue 1361233004:
Implement IIRFilter node for WebAudio. (Closed)
Base URL: https://chromium.googlesource.com/chromium/src.git@master