LayoutTests/webaudio/osc-low-freq.html - Issue 1180613007: Allow larger arrays up to size 8192 for PeriodicWave

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Issue 1180613007: Allow larger arrays up to size 8192 for PeriodicWave (Closed) Base URL: svn://svn.chromium.org/blink/trunk

Patch Set: Created 5 years, 5 months ago

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	1 <!doctype html>

	2 <html>

	3 <head>

	4 <title>Test Custom Oscillator at Very Low Frequency</title>

	5 <script src="../resources/js-test.js"></script>

	6 <script src="resources/compatibility.js"></script>

	7 <script src="resources/audio-testing.js"></script>

	8 </head>

	9

	10 <body>

	11 <script>

	12 description("Test Custom Oscillator at Very Low Frequency");

	13 window.jsTestIsAsync = true;

	14

	15 // Create a custom oscillator and verify that the parts of a periodic wave that should be

	16 // ignored really are ignored.

	17

	18 var sampleRate = 48000;

	19 var highSampleRate = 192000;
	hongchan 2015/07/22 21:01:19 This is unused. This is unused. Raymond Toy 2015/07/23 15:33:09 Done. Show quoted text On 2015/07/22 21:01:19, hoch wrote: > This is unused. Done.
	20

	21 // The desired frequency of the oscillator. The value to be used depends on the

	22 // implementation of the PeriodicWave and should be less than then lowest fundamental

	23 // frequency. The lowest frequency is the Nyquist frequency divided by the max number of

	24 // partials used for the FFT. In the current implementation, the max numbe r of partials is

	25 // 2048 so the lowest frequency is 24000/2048 = 11.78 Hz.
	hongchan 2015/07/22 21:01:19 Partials are not linearly arranged over the freque Partials are not linearly arranged over the frequency range, so not sure if 11.78Hz is the right value. I might ask you more explanation in person. Raymond Toy 2015/07/23 15:33:09 I've rewritten the comment. Let me if it's better. Show quoted text On 2015/07/22 21:01:19, hoch wrote: > Partials are not linearly arranged over the frequency range, so not sure if > 11.78Hz is the right value. I might ask you more explanation in person. I've rewritten the comment. Let me if it's better.
	26 var desiredFrequencyHz = 1;

	27

	28 // Minimum allowed SNR between the actual oscillator and the expected resu lt. Experimentally

	29 // determined.

	30 var snrThreshold = 130;

	31

	32 var context;

	33 var osc;

	34 var actual;

	35

	36 var audit = Audit.createTaskRunner();

	37

	38 function checkSineResult(result, freq, rate) {
	hongchan 2015/07/22 21:01:19 Perhaps would \|checkCosineResult\| fit better for t Perhaps would \|checkCosineResult\| fit better for the task? Also can we rename \|rate\|? Raymond Toy 2015/07/23 15:33:09 Done. Show quoted text On 2015/07/22 21:01:19, hoch wrote: > Perhaps would \|checkCosineResult\| fit better for the task? Also can we rename > \|rate\|? Done.
	39 // Compute the SNR between the actual result and expected cosine wave
	hongchan 2015/07/22 21:01:19 How about moving this to the line 37? Also a perio How about moving this to the line 37? Also a period at the end would be nice. Raymond Toy 2015/07/23 15:33:09 Done. Show quoted text On 2015/07/22 21:01:19, hoch wrote: > How about moving this to the line 37? Also a period at the end would be nice. Done.
	40 var signal = 0;

	41 var noise = 0;

	42 var omega = 2 * Math.PI * freq / rate;

	43

	44 actual = result.getChannelData(0);

	45

	46 for (var k = 0; k < actual.length; ++k) {

	47 var x = Math.cos(omega * k);

	48 var diff = x - actual[k];

	49 signal += x * x;

	50 noise += diff * diff;

	51 }

	52

	53 var snr = 10 * Math.log10(signal / noise);

	54

	55 Should("SNR of " + desiredFrequencyHz + " Hz sine wave", snr).beGreaterT hanOrEqualTo(snrThreshold);

	56 testPassed("PeriodicWave coefficients that must be ignored were correctl y ignored.");

	57 }

	58

	59 function runTest() {

	60 context = new OfflineAudioContext(1, sampleRate, sampleRate);

	61 osc = context.createOscillator();

	62

	63 // Create the custom oscillator. For simplicity of testing, we use just a cosine wave, but

	64 // the initial elements of the real and imaginary parts are explicitly s et to non-zero to

	65 // test that they are ignored.

	66 var r = new Float32Array(2);

	67 var i = new Float32Array(2);

	68 r[0] = 1; // DC component to be ignored

	69 r[1] = 1; // Fundamental

	70 i[0] = 1; // Sine term that doesn't actually exist in a Fourier series

	71 i[1] = 0;

	72 var wave = context.createPeriodicWave(r, i);

	73

	74 osc.setPeriodicWave(wave);

	75 osc.frequency.value = desiredFrequencyHz;

	76 osc.connect(context.destination);

	77 osc.start();

	78 context.startRendering().then(function (b) {
	hongchan 2015/07/22 21:01:19 Let's use \|buffer\| instead of \|b\|. Let's use \|buffer\| instead of \|b\|.
	79 checkSineResult(b, desiredFrequencyHz, sampleRate);

	80 }).then(finishJSTest);

	81 };

	82

	83 runTest();

	84 successfullyParsed = true;

	85 </script>

	86 </body>

	87 </html>

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