| <!doctype html> |
| <html> |
| <head> |
| <title>Test Biquad Tail Output</title> |
| <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 Biquad Tail Output"); |
| window.jsTestIsAsync = true; |
| |
| // A high sample rate shows the issue more clearly. |
| var sampleRate = 192000; |
| // Some short duration because we don't need to run the test for very long. |
| var testDurationSec = 0.5; |
| var testDurationFrames = testDurationSec * sampleRate; |
| |
| // Amplitude experimentally determined to give a biquad output close to 1. (No attempt was |
| // made to produce exactly 1; it's not needed.) |
| var sourceAmplitude = 100; |
| |
| // The output of the biquad filter should not change by more than this much between output |
| // samples. Threshold was determined experimentally. |
| var glitchThreshold = 0.0129; |
| |
| // Test that a Biquad filter doesn't have it's output terminated because the input has gone |
| // away. Generally, when a source node is finished, it disconnects itself from any downstream |
| // nodes. This is the correct behavior. Nodes that have no inputs (disconnected) are |
| // generally assumed to output zeroes. This is also desired behavior. However, biquad |
| // filters have memory so they should not suddenly output zeroes when the input is |
| // disconnected. This test checks to see if the output doesn't suddenly change to zero. |
| function runTest() { |
| var context = new OfflineAudioContext(1, testDurationFrames, sampleRate); |
| |
| // Create an impulse source. |
| var buffer = context.createBuffer(1, 1, context.sampleRate); |
| buffer.getChannelData(0)[0] = sourceAmplitude; |
| var source = context.createBufferSource(); |
| source.buffer = buffer; |
| |
| // Create the biquad filter. It doesn't really matter what kind, so the default filter type |
| // and parameters is fine. Connect the source to it. |
| var biquad = context.createBiquadFilter(); |
| source.connect(biquad); |
| biquad.connect(context.destination); |
| |
| source.start(); |
| |
| context.startRendering().then(function(result) { |
| // There should be no large discontinuities in the output |
| var success = true; |
| success = success && Should("Biquad output", result.getChannelData(0)).notGlitch(glitchThreshold); |
| if (success) |
| testPassed("Biquad tail output correctly completed."); |
| else |
| testFailed("Biquad tail output not correctly completed."); |
| }).then(finishJSTest); |
| } |
| |
| runTest(); |
| successfullyParsed = true; |
| </script> |
| </body> |
| </html> |
