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Side by Side Diff: LayoutTests/webaudio/osc-sine-sweep-snr.html

Issue 670863002: Rebase oscillator sine test result. (Closed) Base URL: svn://svn.chromium.org/blink/trunk
Patch Set: Created 6 years, 1 month ago
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1 <!doctype html>
2 <html>
3 <head>
4 <title>Test Oscillator Node: sine</title>
5 <script src="resources/compatibility.js"></script>
6 <script src="resources/buffer-loader.js"></script>
7 <script src="../resources/js-test.js"></script>
8 <script src="resources/oscillator-testing.js"></script>
9 </head>
10
11 <body>
12 <script>
13 // See oscillator-sine.html for more info on the actual wave shape.
14 //
15 // This test is a partial duplicate of oscillator-sine but is designed t o be less sensitive
16 // to the actual output versus the reference. Instead of requiring an ex act match, we check
17 // several criteria to pass the test. The SNR between the actual and exp ected signals must
18 // be large enough. The maximum difference must be below a threshold, a nd the actual number
19 // of points that are different must be below a threshold.
20
21 var sampleRate = 44100.0;
22 var nyquist = 0.5 * sampleRate;
23 var lengthInSeconds = 4;
24 var lowFrequency = 10;
25 var highFrequency = nyquist + 2000; // go slightly higher than nyquist t o make sure we generate silence there
26 var context = 0;
27 var reference = 0;
28 var renderedData = 0;
29 var signalPower = 0;
30 var noisePower = 0;
31
32 // Scaling factor for converting the 16-bit WAV data to float (and vice- versa).
33 var waveScaleFactor = 32768;
34
35 // Thresholds for verifying the test passes. The thresholds are experim entally determined.
36
37 // SNR must be greater than this to pass the test.
38 // Q: Why is the SNR threshold not infinity?
39 // A: The reference result is a 16-bit WAV file, so it won't compare exa ctly with the
40 // floating point result.
41 var thresholdSNR = 86.58;
42
43 // Max diff must be less than this to pass the test.
44 var thresholdDiff = 2.9 / waveScaleFactor;
45
46 // Count the number of differences between the expected and actual resul t. The tests passes
47 // if the count is less than this threshold.
48 var thresholdDiffCount = 5850;
49
50 function db(sPower, nPower)
51 {
52 if (nPower == 0 && sPower > 0) {
53 return 1000;
54 }
55 return 10 * Math.log10(sPower / nPower);
56 }
57
58 function checkResult (event) {
59 renderedData = event.renderedBuffer.getChannelData(0);
60 // Compute signal to noise ratio between the result and the referenc e. Also keep track
61 // of the max difference (and position).
62
63 var maxError = -1;
64 var errorPosition = -1;
65 var diffCount = 0;
66
67 for (var k = 0; k < renderedData.length; ++k) {
68 var diff = renderedData[k] - reference[k];
69 noisePower += diff * diff;
70 signalPower += reference[k] * reference[k];
71 if (Math.abs(diff) > maxError) {
72 maxError = Math.abs(diff);
73 errorPosition = k;
74 }
75 // The reference file is a 16-bit WAV file, so we will never get an exact match
76 // between it and the actual floating-point result.
77 if (diff > 1/waveScaleFactor) {
78 diffCount++;
79 }
80 }
81
82 var snr = db(signalPower, noisePower);
83 if (snr < thresholdSNR) {
84 testFailed("Expected SNR of " + thresholdSNR + " dB, but actual SNR is " + snr + " dB");
85 } else {
86 testPassed("Exceeded SNR threshold of " + thresholdSNR + " dB");
87 }
88
89 if (maxError > thresholdDiff) {
90 testFailed("Maximum difference of " + (maxError * waveScaleFacto r) + " at "
91 + errorPosition + " exceeded threshold of " + (thresholdDiff * waveScaleFactor)
92 + " ulp (16-bits)");
93 } else {
94 testPassed("Maximum difference below threshold of "
95 + (thresholdDiff * waveScaleFactor) + " ulp (16-bits)");
96 }
97 if (diffCount > thresholdDiffCount) {
98 testFailed(diffCount + " differences found but expected no more than " + thresholdDiffCount);
99 } else {
100 testPassed("Number of differences between actual and expected re sult is less than " + thresholdDiffCount);
101 }
102
103 finishJSTest();
104 }
105
106 function finishedLoading(bufferList) {
107 reference = bufferList[0].getChannelData(0);
108 generateExponentialOscillatorSweep(context, "sine");
109 context.oncomplete = checkResult;
110 context.startRendering();
111 }
112
113 function runTest () {
114 window.jsTestIsAsync = true;
115
116 // Create offline audio context.
117 context = new OfflineAudioContext(1, sampleRate * lengthInSeconds, s ampleRate);
118
119 bufferLoader = new BufferLoader(
120 context,
121 [ "oscillator-sine-expected.wav" ],
122 finishedLoading);
123
124 bufferLoader.load();
125 }
126
127 runTest();
128 successfullyParsed = true;
129 </script>
130 </body>
131 </html>
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