| <!DOCTYPE html> |
| <html> |
| |
| <head> |
| <script src="../resources/js-test.js"></script> |
| <script src="resources/compatibility.js"></script> |
| <script src="resources/audio-testing.js"></script> |
| </head> |
| |
| <body> |
| <script> |
| description('Test the late call of start(0) of BufferSource.'); |
| window.jsTestIsAsync = true; |
| |
| var renderQuantum = 128; |
| |
| var sampleRate = 44100; |
| var renderDuration = 0.25; |
| var startTime = 0.5 * renderDuration; |
| |
| var audit = Audit.createTaskRunner(); |
| |
| // Calculate the index for actual start time. |
| function getStartIndex(time) { |
| var startIndex = time * sampleRate; |
| return startIndex -= (startIndex) % renderQuantum; |
| } |
| |
| // Get the index of value change. |
| function getValueChangeIndex(array, targetValue) { |
| return array.findIndex(function (element, index) { |
| if (element === targetValue) |
| return true; |
| }); |
| } |
| |
| audit.defineTask('test-late-start', function (done) { |
| var context = new OfflineAudioContext(1, renderDuration * sampleRate, sampleRate); |
| var dcOffsetbuffer = createConstantBuffer(context, 1, 1.0); |
| var source = context.createBufferSource(); |
| source.buffer = dcOffsetbuffer; |
| source.loop = true; |
| source.connect(context.destination); |
| |
| // Schedule source.start(0) at 0.01 second. The specified timing of |
| // start() call is already passed in terms of the context time. So the |
| // argument |0| will be clamped to the current context time. |
| // |
| // With the sample rate of 44100, 0.01 second is 441 samples. Rounding |
| // it down to the render quantum gives 384 samples. This is clearly larger |
| // than a single render quantum. |
| // |
| // See issue: crbug.com/462167 |
| context.suspend(startTime).then(function () { |
| source.start(0); |
| context.resume(); |
| }); |
| |
| // Start rendering and verify result: this verifies if 1) the rendered |
| // buffer contains at least one non-zero value and 2) the non-zero value is |
| // found later than the first output sample. |
| context.startRendering().then(function (buffer) { |
| |
| var channelData = buffer.getChannelData(0); |
| var startIndex = getStartIndex(startTime); |
| var nonZeroValueIndex = getValueChangeIndex(channelData, 1.0); |
| |
| Should('The output', channelData).containValues([0, 1]); |
| Should('The index of value change', nonZeroValueIndex) |
| .beEqualTo(startIndex); |
| |
| if (nonZeroValueIndex === 0) |
| testFailed('The first sample was non-zero value. It should be zero.'); |
| else |
| testPassed('The rendered buffer contains non-zero values after the first sample.'); |
| |
| }).then(done); |
| }); |
| |
| audit.defineTask('finish-test', function (done) { |
| done(); |
| finishJSTest(); |
| }); |
| |
| audit.runTasks(); |
| |
| successfullyParsed = true; |
| </script> |
| </body> |
| |
| </html> |
