| OLD | NEW |
|---|
| (Empty) | |
| 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/audio-testing.js"></script> |
| 7 <title>Test OscillatorNode with Negative Frequency</title> |
| 8 </head> |
| 9 |
| 10 <body> |
| 11 <script> |
| 12 description("Test OscillatorNode with Negative Frequency."); |
| 13 window.jsTestIsAsync = true; |
| 14 |
| 15 // Some arbitrary sample rate for the offline context. |
| 16 var sampleRate = 48000; |
| 17 var renderDuration = 1; |
| 18 var renderFrames = renderDuration * sampleRate; |
| 19 |
| 20 var audit = Audit.createTaskRunner(); |
| 21 |
| 22 audit.defineTask("sine", function (done) { |
| 23 runTest({ |
| 24 message: "Sum of positive and negative frequency sine oscillators", |
| 25 type: "sine", |
| 26 threshold: 4.1724e-7 |
| 27 }).then(done); |
| 28 }); |
| 29 |
| 30 audit.defineTask("square", function (done) { |
| 31 runTest({ |
| 32 message: "Sum of positive and negative frequency square oscillators", |
| 33 type: "square", |
| 34 threshold: 4.3959e-6 |
| 35 }).then(done); |
| 36 }); |
| 37 |
| 38 audit.defineTask("sawtooth", function (done) { |
| 39 runTest({ |
| 40 message: "Sum of positive and negative frequency sawtooth oscillators"
, |
| 41 type: "sawtooth", |
| 42 threshold: 4.3735e-6 |
| 43 }).then(done); |
| 44 }); |
| 45 |
| 46 audit.defineTask("triangle", function (done) { |
| 47 runTest({ |
| 48 message: "Sum of positive and negative frequency triangle oscillators"
, |
| 49 type: "triangle", |
| 50 threshold: 3.5763e-7 |
| 51 }).then(done); |
| 52 }); |
| 53 |
| 54 audit.defineTask("auto-sawtooth", function (done) { |
| 55 runTest({ |
| 56 message: "Sum of positive and negative frequency-ramped sawtooth oscil
lators", |
| 57 type: "sawtooth", |
| 58 automation: { |
| 59 type: "linearRampToValueAtTime", |
| 60 startTime: 0, |
| 61 endTime: renderDuration / 2, |
| 62 startFrequency: 440, |
| 63 endFrequency: sampleRate / 4 |
| 64 }, |
| 65 threshold: 4.1202e-6 |
| 66 }).then(done); |
| 67 }); |
| 68 |
| 69 audit.defineTask("periodic-wave", function (done) { |
| 70 // Test negative frequencies for a custom oscillator. Two channels are |
| 71 // needed for the context; one for the expected result, and one for the |
| 72 // actual, as explained below. |
| 73 var context = new OfflineAudioContext(2, renderFrames, sampleRate); |
| 74 |
| 75 var oscPositive = context.createOscillator(); |
| 76 var oscNegative = context.createOscillator(); |
| 77 |
| 78 // The Fourier coefficients for our custom oscillator. The actual value
s |
| 79 // not important. The waveform for our custom oscillator is |
| 80 // |
| 81 // x(t) = sum(real[k]*cos(2*%pi*f*k/Fs), k, 1) |
| 82 // + sum(imag[k]*sin(2*%pi*f*k/Fs), k, 0) |
| 83 // |
| 84 // With a negative frequency we have |
| 85 // |
| 86 // x(t) = sum(real[k]*cos(2*%pi*(-f)*k/Fs), k, 1) |
| 87 // + sum(imag[k]*sin(2*%pi*(-f)*k/Fs), k, 0) |
| 88 // |
| 89 // = sum(real[k]*cos(2*%pi*f*k/Fs), k, 1) |
| 90 // + sum((-imag[k])*sin(2*%pi*f*k/Fs), k, 0) |
| 91 // |
| 92 // That is, when the frequency is inverted, it behaves as if the |
| 93 // coefficients of the imaginary part are inverted. |
| 94 // |
| 95 // Thus, the test is to create two custom oscillators. The second |
| 96 // osillator uses the same PeriodicWave as the first except the |
| 97 // imaginary coefficients are inverted. This second oscillator also |
| 98 // gets a negative frequency. The combination of the two results in an |
| 99 // oscillator that is the same as the first with gain of 2. |
| 100 var real = [0, 1, 1]; |
| 101 var imag = [0, 1, 1]; |
| 102 |
| 103 var wavePositive = context.createPeriodicWave( |
| 104 Float32Array.from(real), |
| 105 Float32Array.from(imag)); |
| 106 var waveNegative = context.createPeriodicWave( |
| 107 Float32Array.from(real), |
| 108 Float32Array.from(imag.map(x => -x))); |
| 109 |
| 110 oscPositive.setPeriodicWave(wavePositive); |
| 111 oscNegative.setPeriodicWave(waveNegative); |
| 112 |
| 113 oscPositive.frequency.value = 440; |
| 114 oscNegative.frequency.value = -oscPositive.frequency.value; |
| 115 |
| 116 var merger = context.createChannelMerger(2); |
| 117 var gain = context.createGain(); |
| 118 |
| 119 // As explained above, the expected result should be positive frequency |
| 120 // oscillator but with a gain of 2. |
| 121 gain.gain.value = 2; |
| 122 oscPositive.connect(gain); |
| 123 gain.connect(merger, 0, 0); |
| 124 |
| 125 // Sum the positive and negative frequency oscillators by using the same |
| 126 // input to the merger. |
| 127 oscPositive.connect(merger, 0, 1); |
| 128 oscNegative.connect(merger, 0, 1); |
| 129 |
| 130 merger.connect(context.destination); |
| 131 |
| 132 oscPositive.start(); |
| 133 oscNegative.start(); |
| 134 |
| 135 context.startRendering().then(function (buffer) { |
| 136 var expected = buffer.getChannelData(0); |
| 137 var actual = buffer.getChannelData(1); |
| 138 |
| 139 Should("Sum of positive and negative frequency custom oscillators", |
| 140 actual, { |
| 141 verbose: true, |
| 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).beCloseToArray(zero, options.threshold
|| 0); |
| 194 }); |
| 195 } |
| 196 </script> |
| 197 </body> |
| 198 </html> |
| OLD | NEW |
|---|
Chromium Code Reviews
Issue 2059823002:
Use correct value for Oscillator.frequency.minValue (Closed)
Base URL: https://chromium.googlesource.com/chromium/src.git@master