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| 1 <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"> | |
| 2 <html> | |
| 3 <head> | |
| 4 <script src="../resources/js-test.js"></script> | |
| 5 <script src="resources/compatibility.js"></script> | |
| 6 <script src="resources/audit-util.js"></script> | |
| 7 <script src="resources/audio-testing.js"></script> | |
| 8 </head> | |
| 9 | |
| 10 <body> | |
| 11 <div id="description"></div> | |
| 12 <div id="console"></div> | |
| 13 | |
| 14 <script> | |
| 15 description("Test scaling of FFT data for AnalyserNode"); | |
| 16 | |
| 17 // The number of analysers. We have analysers from size for each of the po
ssible sizes of 32, | |
| 18 // 64, 128, 256, 512, 1024 and 2048 for a total of 7. | |
| 19 var numberOfAnalysers = 7; | |
| 20 var sampleRate = 44100; | |
| 21 var nyquistFrequency = sampleRate / 2; | |
| 22 | |
| 23 // Frequency of the sine wave test signal. Should be high enough so that
we get at least one | |
| 24 // full cycle for the 32-point FFT. This should also be such that the fre
quency should be | |
| 25 // exactly in one of the FFT bins for each of the possible FFT sizes. | |
| 26 var oscFrequency = nyquistFrequency/16; | |
| 27 | |
| 28 // The actual peak values from each analyser. Useful for examining the re
sults in Chrome. | |
| 29 var peakValue = new Array(numberOfAnalysers); | |
| 30 | |
| 31 // For a 0dBFS sine wave, we would expect the FFT magnitude to be 0dB as w
ell, but the | |
| 32 // analyzer node applies a Blackman window (to smooth the estimate). This
reduces the energy | |
| 33 // of the signal so the FFT peak is less than 0dB. The threshold value gi
ven here was | |
| 34 // determined experimentally. | |
| 35 // | |
| 36 // See https://code.google.com/p/chromium/issues/detail?id=341596. | |
| 37 var peakThreshold = [-14.43, -13.56, -13.56, -13.56, -13.56, -13.56, -13.5
6]; | |
| 38 | |
| 39 var allTestsPassed = true; | |
| 40 | |
| 41 function checkResult(order, analyser) { | |
| 42 return function () { | |
| 43 var index = order - 5; | |
| 44 var fftSize = 1 << order; | |
| 45 var fftData = new Float32Array(fftSize); | |
| 46 analyser.getFloatFrequencyData(fftData); | |
| 47 | |
| 48 // Compute the frequency bin that should contain the peak. | |
| 49 var expectedBin = analyser.frequencyBinCount * (oscFrequency / nyq
uistFrequency); | |
| 50 | |
| 51 // Find the actual bin by finding the bin containing the peak. | |
| 52 var actualBin = 0; | |
| 53 peakValue[index] = -1000; | |
| 54 for (k = 0; k < analyser.frequencyBinCount; ++k) { | |
| 55 if (fftData[k] > peakValue[index]) { | |
| 56 actualBin = k; | |
| 57 peakValue[index] = fftData[k]; | |
| 58 } | |
| 59 } | |
| 60 | |
| 61 var success = true; | |
| 62 | |
| 63 if (actualBin == expectedBin) { | |
| 64 testPassed("Actual FFT peak in the expected position (" + expe
ctedBin + ")."); | |
| 65 } else { | |
| 66 success = false; | |
| 67 testFailed("Actual FFT peak (" + actualBin + ") differs from e
xpected (" + expectedBin + ")."); | |
| 68 } | |
| 69 | |
| 70 if (peakValue[index] >= peakThreshold[index]) { | |
| 71 testPassed("Peak value is near " + peakThreshold[index] + " dB
FS as expected."); | |
| 72 } else { | |
| 73 success = false; | |
| 74 testFailed("Peak value of " + peakValue[index] | |
| 75 + " is incorrect. (Expected approximately " | |
| 76 + peakThreshold[index] + ")."); | |
| 77 } | |
| 78 | |
| 79 if (success) { | |
| 80 testPassed("Analyser correctly scaled FFT data of size " + fft
Size); | |
| 81 } else { | |
| 82 testFailed("Analyser incorrectly scaled FFT data of size " + f
ftSize); | |
| 83 } | |
| 84 allTestsPassed = allTestsPassed && success; | |
| 85 | |
| 86 if (fftSize == 2048) { | |
| 87 if (allTestsPassed) { | |
| 88 testPassed("All Analyser tests passed."); | |
| 89 } else { | |
| 90 testFailed("At least one Analyser test failed."); | |
| 91 } | |
| 92 | |
| 93 finishJSTest(); | |
| 94 } | |
| 95 } | |
| 96 } | |
| 97 | |
| 98 function runTests() { | |
| 99 if (window.testRunner) { | |
| 100 testRunner.dumpAsText(); | |
| 101 testRunner.waitUntilDone(); | |
| 102 } | |
| 103 | |
| 104 window.jsTestIsAsync = true; | |
| 105 | |
| 106 // Test each analyser size from order 5 (size 32) to 11 (size 2048). | |
| 107 for (order = 5; order < 12; ++order) { | |
| 108 // Create a new offline context for each analyser test with the nu
mber of samples | |
| 109 // exactly equal to the fft size. This ensures that the analyser
node gets the | |
| 110 // expected data from the oscillator. | |
| 111 var context = new OfflineAudioContext(1, 1 << order, sampleRate); | |
| 112 // Use a sine wave oscillator as the reference source signal. | |
| 113 var osc = context.createOscillator(); | |
| 114 osc.type = "sine"; | |
| 115 osc.frequency.value = oscFrequency; | |
| 116 osc.connect(context.destination); | |
| 117 | |
| 118 var analyser = context.createAnalyser(); | |
| 119 // No smoothing to simplify the analysis of the result. | |
| 120 analyser.smoothingTimeConstant = 0; | |
| 121 analyser.fftSize = 1 << order; | |
| 122 osc.connect(analyser); | |
| 123 | |
| 124 osc.start(); | |
| 125 context.oncomplete = checkResult(order, analyser); | |
| 126 context.startRendering(); | |
| 127 } | |
| 128 } | |
| 129 | |
| 130 runTests(); | |
| 131 successfullyParsed = true; | |
| 132 </script> | |
| 133 </body> | |
| 134 </html> | |
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Chromium Code Reviews
Issue 2581463002:
Refactor WebAudio test directory (Closed)
