Chromium Code Reviews Chromium Code Reviews
Issue 1180613007:
Allow larger arrays up to size 8192 for PeriodicWave (Closed)
Base URL: svn://svn.chromium.org/blink/trunk| Index: LayoutTests/webaudio/osc-low-freq.html |
| diff --git a/LayoutTests/webaudio/osc-low-freq.html b/LayoutTests/webaudio/osc-low-freq.html |
| new file mode 100644 |
| index 0000000000000000000000000000000000000000..706bcf8655ea176c3353c157d2fd783d29911711 |
| --- /dev/null |
| +++ b/LayoutTests/webaudio/osc-low-freq.html |
| @@ -0,0 +1,87 @@ |
| +<!doctype html> |
| +<html> |
| + <head> |
| + <title>Test Custom Oscillator at Very Low Frequency</title> |
| + <script src="../resources/js-test.js"></script> |
| + <script src="resources/compatibility.js"></script> |
| + <script src="resources/audio-testing.js"></script> |
| + </head> |
| + |
| + <body> |
| + <script> |
| + description("Test Custom Oscillator at Very Low Frequency"); |
| + window.jsTestIsAsync = true; |
| + |
| + // Create a custom oscillator and verify that the parts of a periodic wave that should be |
| + // ignored really are ignored. |
| + |
| + var sampleRate = 48000; |
| + var highSampleRate = 192000; |
|
hongchan
2015/07/22 21:01:19
This is unused.
Raymond Toy
2015/07/23 15:33:09
Done.
|
| + |
| + // The desired frequency of the oscillator. The value to be used depends on the |
| + // implementation of the PeriodicWave and should be less than then lowest fundamental |
| + // frequency. The lowest frequency is the Nyquist frequency divided by the max number of |
| + // partials used for the FFT. In the current implementation, the max number of partials is |
| + // 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
Raymond Toy
2015/07/23 15:33:09
I've rewritten the comment. Let me if it's better.
|
| + var desiredFrequencyHz = 1; |
| + |
| + // Minimum allowed SNR between the actual oscillator and the expected result. Experimentally |
| + // determined. |
| + var snrThreshold = 130; |
| + |
| + var context; |
| + var osc; |
| + var actual; |
| + |
| + var audit = Audit.createTaskRunner(); |
| + |
| + function checkSineResult(result, freq, rate) { |
|
hongchan
2015/07/22 21:01:19
Perhaps would |checkCosineResult| fit better for t
Raymond Toy
2015/07/23 15:33:09
Done.
|
| + // 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
Raymond Toy
2015/07/23 15:33:09
Done.
|
| + var signal = 0; |
| + var noise = 0; |
| + var omega = 2 * Math.PI * freq / rate; |
| + |
| + actual = result.getChannelData(0); |
| + |
| + for (var k = 0; k < actual.length; ++k) { |
| + var x = Math.cos(omega * k); |
| + var diff = x - actual[k]; |
| + signal += x * x; |
| + noise += diff * diff; |
| + } |
| + |
| + var snr = 10 * Math.log10(signal / noise); |
| + |
| + Should("SNR of " + desiredFrequencyHz + " Hz sine wave", snr).beGreaterThanOrEqualTo(snrThreshold); |
| + testPassed("PeriodicWave coefficients that must be ignored were correctly ignored."); |
| + } |
| + |
| + function runTest() { |
| + context = new OfflineAudioContext(1, sampleRate, sampleRate); |
| + osc = context.createOscillator(); |
| + |
| + // Create the custom oscillator. For simplicity of testing, we use just a cosine wave, but |
| + // the initial elements of the real and imaginary parts are explicitly set to non-zero to |
| + // test that they are ignored. |
| + var r = new Float32Array(2); |
| + var i = new Float32Array(2); |
| + r[0] = 1; // DC component to be ignored |
| + r[1] = 1; // Fundamental |
| + i[0] = 1; // Sine term that doesn't actually exist in a Fourier series |
| + i[1] = 0; |
| + var wave = context.createPeriodicWave(r, i); |
| + |
| + osc.setPeriodicWave(wave); |
| + osc.frequency.value = desiredFrequencyHz; |
| + osc.connect(context.destination); |
| + osc.start(); |
| + context.startRendering().then(function (b) { |
|
hongchan
2015/07/22 21:01:19
Let's use |buffer| instead of |b|.
|
| + checkSineResult(b, desiredFrequencyHz, sampleRate); |
| + }).then(finishJSTest); |
| + }; |
| + |
| + runTest(); |
| + successfullyParsed = true; |
| + </script> |
| + </body> |
| +</html> |
