| <!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 if ChannelMergerNode runs correctly in a cycle."); |
| window.jsTestIsAsync = true; |
| |
| // This specific sample rate is chosen to avoid the round/truncation error |
| // in delay time. See: crbug.com/448801 |
| var sampleRate = 32768; |
| |
| // Web Audio API's rendering quantum. |
| var renderingQuantum = 128; |
| |
| // 4x of rendering quantum. This is to make the rendered result long enough |
| // so that we can observe the delayed output. |
| var renderLength = renderingQuantum * 4; |
| |
| // 1x rendering quantum of delay. |
| var delayTime = renderingQuantum / sampleRate; |
| |
| // Use 2 channels as a test case. |
| var numberOfChannels = 2; |
| |
| var audit = Audit.createTaskRunner(); |
| |
| audit.defineTask('merger-cyclic-graph', function (done) { |
| |
| var context = new OfflineAudioContext( |
| numberOfChannels, renderLength, sampleRate |
| ); |
| var merger = context.createChannelMerger(2); |
| var delay = context.createDelay(); |
| var source = context.createBufferSource(); |
| |
| // Create a mono source buffer filled with '1'. |
| source.buffer = createTestingAudioBuffer(context, 1, renderLength); |
| |
| delay.delayTime.value = delayTime; |
| |
| // Connect the source to input 0 of the merger. Connect the output of |
| // the merger to a delay node whose output is then connected to input 1 |
| // of the merger. See: crbug.com/442925 |
| source.connect(merger, 0, 0); |
| delay.connect(merger, 0, 1); |
| merger.connect(delay); |
| merger.connect(context.destination); |
| source.start(); |
| |
| context.startRendering().then(function (buffer) { |
| // Expected output values: the output of delay node will be a stereo |
| // signal of [1, 0]. When it feeds back to the 2nd input of merger node, |
| // the stereo channel will be summed to mono resulting in 0.5. |
| var expected_left = []; |
| var expected_right = []; |
| |
| for (var i = 0; i < renderLength; i++) { |
| // Note that the delayed channel will be zero for the first 128 samples |
| // due to the cyclic audio graph, the second 128 sample will be also |
| // zero because of 128 samples delay. |
| expected_left[i] = 1.0; |
| expected_right[i] = (i < renderingQuantum * 2) ? 0.0 : 0.5; |
| } |
| |
| for (i = 0; i < buffer.numberOfChannels; i++) { |
| var actual_left = buffer.getChannelData(0); |
| var actual_right = buffer.getChannelData(1); |
| for (var j = 0; j < renderLength; j++) { |
| if (expected_left[j] !== actual_left[j]) { |
| testFailed('The value ' + actual_left[j] + |
| 'in the left channel did not match the expected value ' + |
| expected_left[j] + ' at the index ' + j + '.'); |
| done(); |
| return; |
| } |
| if (expected_right[j] !== actual_right[j]) { |
| testFailed('The value ' + actual_left[j] + |
| 'in the right channel did not match the expected value ' + |
| expected_left[j] + ' at the index ' + j + '.'); |
| done(); |
| return; |
| } |
| } |
| } |
| |
| testPassed("ChannerMergerNode passed cyclic audio graph test."); |
| done(); |
| }); |
| |
| }); |
| |
| audit.defineTask('finish', function (done) { |
| finishJSTest(); |
| done(); |
| }); |
| |
| audit.runTasks( |
| 'merger-cyclic-graph', |
| 'finish' |
| ); |
| |
| successfullyParsed = true; |
| </script> |
| </body> |
| |
| </html> |
