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| 1 <!doctype html> | |
| 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 <title>Test OscillatorNode with Negative Frequency</title> | |
| 9 </head> | |
| 10 | |
| 11 <body> | |
| 12 <script> | |
| 13 description("Test OscillatorNode with Negative Frequency."); | |
| 14 window.jsTestIsAsync = true; | |
| 15 | |
| 16 // Some arbitrary sample rate for the offline context. | |
| 17 var sampleRate = 48000; | |
| 18 var renderDuration = 1; | |
| 19 var renderFrames = renderDuration * sampleRate; | |
| 20 | |
| 21 var audit = Audit.createTaskRunner(); | |
| 22 | |
| 23 audit.defineTask("sine", function (done) { | |
| 24 runTest({ | |
| 25 message: "Sum of positive and negative frequency sine oscillators", | |
| 26 type: "sine", | |
| 27 threshold: 4.7684e-7 | |
| 28 }).then(done); | |
| 29 }); | |
| 30 | |
| 31 audit.defineTask("square", function (done) { | |
| 32 runTest({ | |
| 33 message: "Sum of positive and negative frequency square oscillators", | |
| 34 type: "square", | |
| 35 threshold: 4.4108e-6 | |
| 36 }).then(done); | |
| 37 }); | |
| 38 | |
| 39 audit.defineTask("sawtooth", function (done) { | |
| 40 runTest({ | |
| 41 message: "Sum of positive and negative frequency sawtooth oscillators"
, | |
| 42 type: "sawtooth", | |
| 43 threshold: 4.3735e-6 | |
| 44 }).then(done); | |
| 45 }); | |
| 46 | |
| 47 audit.defineTask("triangle", function (done) { | |
| 48 runTest({ | |
| 49 message: "Sum of positive and negative frequency triangle oscillators"
, | |
| 50 type: "triangle", | |
| 51 threshold: 3.5763e-7 | |
| 52 }).then(done); | |
| 53 }); | |
| 54 | |
| 55 audit.defineTask("auto-sawtooth", function (done) { | |
| 56 runTest({ | |
| 57 message: "Sum of positive and negative frequency-ramped sawtooth oscil
lators", | |
| 58 type: "sawtooth", | |
| 59 automation: { | |
| 60 type: "linearRampToValueAtTime", | |
| 61 startTime: 0, | |
| 62 endTime: renderDuration / 2, | |
| 63 startFrequency: 440, | |
| 64 endFrequency: sampleRate / 4 | |
| 65 }, | |
| 66 threshold: 4.1202e-6 | |
| 67 }).then(done); | |
| 68 }); | |
| 69 | |
| 70 audit.defineTask("periodic-wave", function (done) { | |
| 71 // Test negative frequencies for a custom oscillator. Two channels are | |
| 72 // needed for the context; one for the expected result, and one for the | |
| 73 // actual, as explained below. | |
| 74 var context = new OfflineAudioContext(2, renderFrames, sampleRate); | |
| 75 | |
| 76 var oscPositive = context.createOscillator(); | |
| 77 var oscNegative = context.createOscillator(); | |
| 78 | |
| 79 // The Fourier coefficients for our custom oscillator. The actual value
s | |
| 80 // not important. The waveform for our custom oscillator is | |
| 81 // | |
| 82 // x(t) = sum(real[k]*cos(2*%pi*f*k/Fs), k, 1) | |
| 83 // + sum(imag[k]*sin(2*%pi*f*k/Fs), k, 0) | |
| 84 // | |
| 85 // With a negative frequency we have | |
| 86 // | |
| 87 // x(t) = sum(real[k]*cos(2*%pi*(-f)*k/Fs), k, 1) | |
| 88 // + sum(imag[k]*sin(2*%pi*(-f)*k/Fs), k, 0) | |
| 89 // | |
| 90 // = sum(real[k]*cos(2*%pi*f*k/Fs), k, 1) | |
| 91 // + sum((-imag[k])*sin(2*%pi*f*k/Fs), k, 0) | |
| 92 // | |
| 93 // That is, when the frequency is inverted, it behaves as if the | |
| 94 // coefficients of the imaginary part are inverted. | |
| 95 // | |
| 96 // Thus, the test is to create two custom oscillators. The second | |
| 97 // osillator uses the same PeriodicWave as the first except the | |
| 98 // imaginary coefficients are inverted. This second oscillator also | |
| 99 // gets a negative frequency. The combination of the two results in an | |
| 100 // oscillator that is the same as the first with gain of 2. | |
| 101 var real = [0, 1, 1]; | |
| 102 var imag = [0, 1, 1]; | |
| 103 | |
| 104 var wavePositive = context.createPeriodicWave( | |
| 105 Float32Array.from(real), | |
| 106 Float32Array.from(imag)); | |
| 107 var waveNegative = context.createPeriodicWave( | |
| 108 Float32Array.from(real), | |
| 109 Float32Array.from(imag.map(x => -x))); | |
| 110 | |
| 111 oscPositive.setPeriodicWave(wavePositive); | |
| 112 oscNegative.setPeriodicWave(waveNegative); | |
| 113 | |
| 114 oscPositive.frequency.value = 440; | |
| 115 oscNegative.frequency.value = -oscPositive.frequency.value; | |
| 116 | |
| 117 var merger = context.createChannelMerger(2); | |
| 118 var gain = context.createGain(); | |
| 119 | |
| 120 // As explained above, the expected result should be positive frequency | |
| 121 // oscillator but with a gain of 2. | |
| 122 gain.gain.value = 2; | |
| 123 oscPositive.connect(gain); | |
| 124 gain.connect(merger, 0, 0); | |
| 125 | |
| 126 // Sum the positive and negative frequency oscillators by using the same | |
| 127 // input to the merger. | |
| 128 oscPositive.connect(merger, 0, 1); | |
| 129 oscNegative.connect(merger, 0, 1); | |
| 130 | |
| 131 merger.connect(context.destination); | |
| 132 | |
| 133 oscPositive.start(); | |
| 134 oscNegative.start(); | |
| 135 | |
| 136 context.startRendering().then(function (buffer) { | |
| 137 var expected = buffer.getChannelData(0); | |
| 138 var actual = buffer.getChannelData(1); | |
| 139 | |
| 140 Should("Sum of positive and negative frequency custom oscillators", | |
| 141 actual, { | |
| 142 precision: 6 | |
| 143 }) | |
| 144 .beCloseToArray(expected, 4.7684e-7); | |
| 145 }).then(done); | |
| 146 }); | |
| 147 | |
| 148 | |
| 149 // All done! | |
| 150 audit.defineTask("finish", function (done) { | |
| 151 finishJSTest(); | |
| 152 done(); | |
| 153 }); | |
| 154 | |
| 155 audit.runTasks(); | |
| 156 | |
| 157 function runTest(options) { | |
| 158 // To test if negative frequencies work, create two oscillators. One | |
| 159 // has a positive frequency and the other has a negative frequency. | |
| 160 // Sum the oscillator outputs; the output should be zero because all of | |
| 161 // the builtin oscillator types are odd functions of frequency. | |
| 162 var context = new OfflineAudioContext(1, renderFrames, sampleRate); | |
| 163 | |
| 164 var oscPositive = context.createOscillator(); | |
| 165 var oscNegative = context.createOscillator(); | |
| 166 | |
| 167 oscPositive.type = options.type; | |
| 168 oscNegative.type = oscPositive.type; | |
| 169 | |
| 170 if (options.automation) { | |
| 171 var {type, startTime, endTime, startFrequency, endFrequency} = options
.automation; | |
| 172 oscPositive.frequency.setValueAtTime(startFrequency, startTime); | |
| 173 oscPositive.frequency[type](endFrequency, endTime) | |
| 174 | |
| 175 oscNegative.frequency.setValueAtTime(-startFrequency, startTime); | |
| 176 oscNegative.frequency[type](-endFrequency, endTime) | |
| 177 } else { | |
| 178 oscPositive.frequency.value = 440; | |
| 179 oscNegative.frequency.value = -oscPositive.frequency.value; | |
| 180 } | |
| 181 | |
| 182 oscPositive.connect(context.destination); | |
| 183 oscNegative.connect(context.destination); | |
| 184 | |
| 185 oscPositive.start(); | |
| 186 oscNegative.start(); | |
| 187 | |
| 188 return context.startRendering().then(function (buffer) { | |
| 189 var result = buffer.getChannelData(0); | |
| 190 | |
| 191 var zero = new Float32Array(result.length); | |
| 192 zero.fill(0); | |
| 193 Should(options.message, result, { | |
| 194 verbose: true | |
| 195 }).beCloseToArray(zero, options.threshold || 0); | |
| 196 }); | |
| 197 } | |
| 198 </script> | |
| 199 </body> | |
| 200 </html> | |
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Chromium Code Reviews
Issue 2581463002:
Refactor WebAudio test directory (Closed)
