| <!doctype html> |
| <html> |
| <head> |
| <script src="../resources/js-test.js"></script> |
| <script src="resources/compatibility.js"></script> |
| <script src="resources/audio-testing.js"></script> |
| <title>Test Negative AudioParam.exponentialRampToValueAtTime</title> |
| </head> |
| |
| <body> |
| <script> |
| description("Test AudioParam.exponentialRampToValueAtTime() with Negative Values."); |
| window.jsTestIsAsync = true; |
| |
| var sampleRate = 48000; |
| |
| var audit = Audit.createTaskRunner(); |
| |
| audit.defineTask("both negative values", function (done) { |
| var renderDuration = 0.125; |
| |
| // Create context with two channels. Channel 0 contains the positive-valued exponential and |
| // channel 1 contains the negative-valued exponential. We'll compare the two channels to |
| // verify that they're the same, as they should be. |
| var context = new OfflineAudioContext(2, renderDuration * sampleRate, sampleRate); |
| var source = context.createBufferSource(); |
| source.buffer = createConstantBuffer(context, 1, 1); |
| source.loop = true; |
| |
| // Gain node gp is for the positive-valued exponential ramp, and gn is for the negative-valued |
| // exponential ramp. |
| var gp = context.createGain(); |
| var gn = context.createGain(); |
| var merger = context.createChannelMerger(2); |
| |
| source.connect(gp) |
| .connect(merger, 0, 0); |
| source.connect(gn) |
| .connect(merger, 0, 1); |
| merger.connect(context.destination); |
| |
| gp.gain.setValueAtTime(1, 0); |
| gp.gain.exponentialRampToValueAtTime(2, renderDuration); |
| |
| gn.gain.setValueAtTime(-1, 0); |
| gn.gain.exponentialRampToValueAtTime(-2, renderDuration); |
| |
| source.start(); |
| |
| context.startRendering().then(function (resultBuffer) { |
| // Verify that channels have the same values, except for the sign. |
| var expected = resultBuffer.getChannelData(0); |
| var actual = resultBuffer.getChannelData(1); |
| var inverted = expected.map(sample => -sample); |
| |
| Should("Negative exponential ramp from -1 to -2", actual) |
| .beEqualToArray(inverted); |
| }).then(done); |
| }); |
| |
| audit.defineTask("negative-end", function (done) { |
| // Positive start value and negative end value should just do nothing. |
| var renderDuration = 0.125; |
| var context = new OfflineAudioContext(1, renderDuration * sampleRate, sampleRate); |
| var source = context.createBufferSource(); |
| source.buffer = createConstantBuffer(context, 1, 1); |
| source.loop = true; |
| |
| // Gain node gp is for the positive-valued exponential ramp, and gn is for the negative-valued |
| // exponential ramp. |
| var g = context.createGain(); |
| |
| g.gain.setValueAtTime(2, 0); |
| g.gain.exponentialRampToValueAtTime(-1, renderDuration); |
| |
| source.connect(g) |
| .connect(context.destination); |
| |
| source.start(); |
| |
| context.startRendering().then(function (resultBuffer) { |
| var actual = resultBuffer.getChannelData(0); |
| |
| Should("Exponential ramp from 2 to -1", actual) |
| .beConstantValueOf(2); |
| }).then(done); |
| }); |
| |
| audit.defineTask("positive-end", function (done) { |
| // Positive start value and negative end value should just do nothing. |
| var renderDuration = 0.125; |
| var context = new OfflineAudioContext(1, renderDuration * sampleRate, sampleRate); |
| var source = context.createBufferSource(); |
| source.buffer = createConstantBuffer(context, 1, 1); |
| source.loop = true; |
| |
| var g = context.createGain(); |
| |
| g.gain.setValueAtTime(-1, 0); |
| g.gain.exponentialRampToValueAtTime(1, renderDuration); |
| |
| source.connect(g) |
| .connect(context.destination); |
| source.start(); |
| |
| context.startRendering().then(function (resultBuffer) { |
| var actual = resultBuffer.getChannelData(0); |
| |
| Should("Exponential ramp from -1 to 1", actual) |
| .beConstantValueOf(-1); |
| }).then(done); |
| }); |
| |
| audit.defineTask("propagate", function (done) { |
| // Test propagation of ramp if the exponential ramp start and end values have opposite sign. |
| var renderDuration = 0.125; |
| var linearRampEnd = renderDuration / 4; |
| var exponentialRampEnd = renderDuration / 2; |
| |
| var context = new OfflineAudioContext(1, renderDuration * sampleRate, sampleRate); |
| var source = context.createBufferSource(); |
| source.buffer = createConstantBuffer(context, 1, 1); |
| source.loop = true; |
| |
| var g = context.createGain(); |
| |
| g.gain.setValueAtTime(2, 0); |
| g.gain.linearRampToValueAtTime(-1, linearRampEnd); |
| g.gain.exponentialRampToValueAtTime(1, exponentialRampEnd); |
| |
| source.connect(g) |
| .connect(context.destination); |
| source.start(); |
| |
| context.startRendering().then(function (resultBuffer) { |
| var actual = resultBuffer.getChannelData(0); |
| |
| // Since the start value of the exponential ramp is -1 and the end value is 1, the ramp |
| // should just propagate -1 from the end of the linear ramp "forever". |
| var endFrame = Math.ceil(linearRampEnd * sampleRate); |
| Should("Exponential ramp from -1 to 1 after the end of the linear ramp", |
| actual.slice(endFrame)) |
| .beConstantValueOf(-1); |
| }).then(done); |
| |
| }); |
| |
| audit.defineTask("finish", function (done) { |
| finishJSTest(); |
| done(); |
| }); |
| |
| audit.runTasks(); |
| </script> |
| </body> |
| </html> |
