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diff --git a/dom/media/webaudio/test/blink/convolution-testing.js b/dom/media/webaudio/test/blink/convolution-testing.js
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+var sampleRate = 44100.0;
+
+var renderLengthSeconds = 8;
+var pulseLengthSeconds = 1;
+var pulseLengthFrames = pulseLengthSeconds * sampleRate;
+
+function createSquarePulseBuffer(context, sampleFrameLength) {
+ var audioBuffer = context.createBuffer(1, sampleFrameLength, context.sampleRate);
+
+ var n = audioBuffer.length;
+ var data = audioBuffer.getChannelData(0);
+
+ for (var i = 0; i < n; ++i)
+ data[i] = 1;
+
+ return audioBuffer;
+}
+
+// The triangle buffer holds the expected result of the convolution.
+// It linearly ramps up from 0 to its maximum value (at the center)
+// then linearly ramps down to 0. The center value corresponds to the
+// point where the two square pulses overlap the most.
+function createTrianglePulseBuffer(context, sampleFrameLength) {
+ var audioBuffer = context.createBuffer(1, sampleFrameLength, context.sampleRate);
+
+ var n = audioBuffer.length;
+ var halfLength = n / 2;
+ var data = audioBuffer.getChannelData(0);
+
+ for (var i = 0; i < halfLength; ++i)
+ data[i] = i + 1;
+
+ for (var i = halfLength; i < n; ++i)
+ data[i] = n - i - 1;
+
+ return audioBuffer;
+}
+
+function log10(x) {
+ return Math.log(x)/Math.LN10;
+}
+
+function linearToDecibel(x) {
+ return 20*log10(x);
+}
+
+// Verify that the rendered result is very close to the reference
+// triangular pulse.
+function checkTriangularPulse(rendered, reference) {
+ var match = true;
+ var maxDelta = 0;
+ var valueAtMaxDelta = 0;
+ var maxDeltaIndex = 0;
+
+ for (var i = 0; i < reference.length; ++i) {
+ var diff = rendered[i] - reference[i];
+ var x = Math.abs(diff);
+ if (x > maxDelta) {
+ maxDelta = x;
+ valueAtMaxDelta = reference[i];
+ maxDeltaIndex = i;
+ }
+ }
+
+ // allowedDeviationFraction was determined experimentally. It
+ // is the threshold of the relative error at the maximum
+ // difference between the true triangular pulse and the
+ // rendered pulse.
+ var allowedDeviationDecibels = -129.4;
+ var maxDeviationDecibels = linearToDecibel(maxDelta / valueAtMaxDelta);
+
+ if (maxDeviationDecibels <= allowedDeviationDecibels) {
+ testPassed("Triangular portion of convolution is correct.");
+ } else {
+ testFailed("Triangular portion of convolution is not correct. Max deviation = " + maxDeviationDecibels + " dB at " + maxDeltaIndex);
+ match = false;
+ }
+
+ return match;
+}
+
+// Verify that the rendered data is close to zero for the first part
+// of the tail.
+function checkTail1(data, reference, breakpoint) {
+ var isZero = true;
+ var tail1Max = 0;
+
+ for (var i = reference.length; i < reference.length + breakpoint; ++i) {
+ var mag = Math.abs(data[i]);
+ if (mag > tail1Max) {
+ tail1Max = mag;
+ }
+ }
+
+ // Let's find the peak of the reference (even though we know a
+ // priori what it is).
+ var refMax = 0;
+ for (var i = 0; i < reference.length; ++i) {
+ refMax = Math.max(refMax, Math.abs(reference[i]));
+ }
+
+ // This threshold is experimentally determined by examining the
+ // value of tail1MaxDecibels.
+ var threshold1 = -129.7;
+
+ var tail1MaxDecibels = linearToDecibel(tail1Max/refMax);
+ if (tail1MaxDecibels <= threshold1) {
+ testPassed("First part of tail of convolution is sufficiently small.");
+ } else {
+ testFailed("First part of tail of convolution is not sufficiently small: " + tail1MaxDecibels + " dB");
+ isZero = false;
+ }
+
+ return isZero;
+}
+
+// Verify that the second part of the tail of the convolution is
+// exactly zero.
+function checkTail2(data, reference, breakpoint) {
+ var isZero = true;
+ var tail2Max = 0;
+ // For the second part of the tail, the maximum value should be
+ // exactly zero.
+ var threshold2 = 0;
+ for (var i = reference.length + breakpoint; i < data.length; ++i) {
+ if (Math.abs(data[i]) > 0) {
+ isZero = false;
+ break;
+ }
+ }
+
+ if (isZero) {
+ testPassed("Rendered signal after tail of convolution is silent.");
+ } else {
+ testFailed("Rendered signal after tail of convolution should be silent.");
+ }
+
+ return isZero;
+}
+
+function checkConvolvedResult(trianglePulse) {
+ return function(event) {
+ var renderedBuffer = event.renderedBuffer;
+
+ var referenceData = trianglePulse.getChannelData(0);
+ var renderedData = renderedBuffer.getChannelData(0);
+
+ var success = true;
+
+ // Verify the triangular pulse is actually triangular.
+
+ success = success && checkTriangularPulse(renderedData, referenceData);
+
+ // Make sure that portion after convolved portion is totally
+ // silent. But round-off prevents this from being completely
+ // true. At the end of the triangle, it should be close to
+ // zero. If we go farther out, it should be even closer and
+ // eventually zero.
+
+ // For the tail of the convolution (where the result would be
+ // theoretically zero), we partition the tail into two
+ // parts. The first is the at the beginning of the tail,
+ // where we tolerate a small but non-zero value. The second part is
+ // farther along the tail where the result should be zero.
+
+ // breakpoint is the point dividing the first two tail parts
+ // we're looking at. Experimentally determined.
+ var breakpoint = 12800;
+
+ success = success && checkTail1(renderedData, referenceData, breakpoint);
+
+ success = success && checkTail2(renderedData, referenceData, breakpoint);
+
+ if (success) {
+ testPassed("Test signal was correctly convolved.");
+ } else {
+ testFailed("Test signal was not correctly convolved.");
+ }
+
+ finishJSTest();
+ }
+}