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| 1 <!doctype html> |
| 2 <html> |
| 3 <head> |
| 4 <title>Test Biquad Tail Output</title> |
| 5 <script src="../resources/js-test.js"></script> |
| 6 <script src="resources/compatibility.js"></script> |
| 7 <script src="resources/audio-testing.js"></script> |
| 8 </head> |
| 9 |
| 10 <body> |
| 11 <script> |
| 12 description("Test Biquad Tail Output"); |
| 13 window.jsTestIsAsync = true; |
| 14 |
| 15 // A high sample rate shows the issue more clearly. |
| 16 var sampleRate = 192000; |
| 17 // Some short duration because we don't need to run the test for very long
. |
| 18 var testDurationSec = 0.5; |
| 19 var testDurationFrames = testDurationSec * sampleRate; |
| 20 |
| 21 // Amplitude experimentally determined to give a biquad output close to 1.
(No attempt was |
| 22 // made to produce exactly 1; it's not needed.) |
| 23 var sourceAmplitude = 100; |
| 24 |
| 25 // The output of the biquad filter should not change by more than this muc
h between output |
| 26 // samples. Threshold was determined experimentally. |
| 27 var glitchThreshold = 0.0129; |
| 28 |
| 29 // Test that a Biquad filter doesn't have it's output terminated because t
he input has gone |
| 30 // away. Generally, when a source node is finished, it disconnects itself
from any downstream |
| 31 // nodes. This is the correct behavior. Nodes that have no inputs (disco
nnected) are |
| 32 // generally assumed to output zeroes. This is also desired behavior. Ho
wever, biquad |
| 33 // filters have memory so they should not suddenly output zeroes when the
input is |
| 34 // disconnected. This test checks to see if the output doesn't suddenly c
hange to zero. |
| 35 function runTest() { |
| 36 var context = new OfflineAudioContext(1, testDurationFrames, sampleRate)
; |
| 37 |
| 38 // Create an impulse source. |
| 39 var buffer = context.createBuffer(1, 1, context.sampleRate); |
| 40 buffer.getChannelData(0)[0] = sourceAmplitude; |
| 41 var source = context.createBufferSource(); |
| 42 source.buffer = buffer; |
| 43 |
| 44 // Create the biquad filter. It doesn't really matter what kind, so the
default filter type |
| 45 // and parameters is fine. Connect the source to it. |
| 46 var biquad = context.createBiquadFilter(); |
| 47 source.connect(biquad); |
| 48 biquad.connect(context.destination); |
| 49 |
| 50 source.start(); |
| 51 |
| 52 context.startRendering().then(function(result) { |
| 53 // There should be no large discontinuities in the output |
| 54 var success = true; |
| 55 success = success && Should("Biquad output", result.getChannelData(0))
.notGlitch(glitchThreshold); |
| 56 if (success) |
| 57 testPassed("Biquad tail output correctly completed."); |
| 58 else |
| 59 testFailed("Biquad tail output not correctly completed."); |
| 60 }).then(finishJSTest); |
| 61 } |
| 62 |
| 63 runTest(); |
| 64 successfullyParsed = true; |
| 65 </script> |
| 66 </body> |
| 67 </html> |
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Chromium Code Reviews
Issue 1285073005:
Add special case handling for disconnected BiquadFilter. (Closed)
Base URL: svn://svn.chromium.org/blink/trunk