test_pannerNodeTail.html

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  <title>Test tail time lifetime of PannerNode</title>

  <script src="/tests/SimpleTest/SimpleTest.js"></script>

  <script type="text/javascript" src="webaudio.js"></script>

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<pre id="test">

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// This tests that a PannerNode does not release its reference before

// it finishes emitting sound.

//

// The PannerNode tail time is short, so, when a PannerNode is destroyed on

// the main thread, it is unlikely to notify the graph thread before the tail

// time expires.  However, by adding DelayNodes downstream from the

// PannerNodes, the graph thread can have enough time to notice that a

// DelayNode has been destroyed.

//

// In the current implementation, DelayNodes will take a tail-time reference

// immediately when they receive the first block of sound from an upstream

// node, so this test connects the downstream DelayNodes while the upstream

// nodes are finishing, and then runs GC (on the main thread) before the

// DelayNodes receive any input (on the graph thread).

//

// Web Audio doesn't provide a means to precisely time connect()s but we can

// test that the output of delay nodes matches the output from a reference

// PannerNode that we know will not be GCed.

//

// Another set of delay nodes is added upstream to ensure that the source node

// has removed its self-reference after dispatching its "ended" event.

SimpleTest.waitForExplicitFinish();

const blockSize = 128;

// bufferSize should be long enough that to allow an audioprocess event to be

// sent to the main thread and a connect message to return to the graph

// thread.

const bufferSize = 4096;

const pannerCount = bufferSize / blockSize;

// sourceDelayBufferCount should be long enough to allow the source node

// onended to finish and remove the source self-reference.

const sourceDelayBufferCount = 3;

var gotEnded = false;

// ccDelayLength should be long enough to allow CC to run

var ccDelayBufferCount = 20;

const ccDelayLength = ccDelayBufferCount * bufferSize;

var ctx = new AudioContext();

var testPanners = [];

var referencePanner = new PannerNode(ctx, {panningModel: "HRTF"});

var referenceProcessCount = 0;

var referenceOutput = [new Float32Array(bufferSize),

                       new Float32Array(bufferSize)];

var testProcessor;

var testProcessCount = 0;

function onReferenceOutput(e) {

  switch(referenceProcessCount) {

  case sourceDelayBufferCount - 1:

    // The panners are about to finish.

    if (!gotEnded) {

      todo(false, "Source hasn't ended.  Increase sourceDelayBufferCount?");

    // Connect each PannerNode output to a downstream DelayNode,

    // and connect ScriptProcessors to compare test and reference panners.

    var delayDuration = ccDelayLength / ctx.sampleRate;

    for (var i = 0; i < pannerCount; ++i) {

      var delay = ctx.createDelay(delayDuration);

      delay.delayTime.value = delayDuration;

      delay.connect(testProcessor);

      testPanners[i].connect(delay);

    testProcessor = null;

    testPanners = null;

    // The panning effect is linear so only one reference panner is required.

    // This also checks that the individual panners don't chop their output

    // too soon.

    referencePanner.connect(e.target);

    // Assuming the above operations have already scheduled an event to run in

    // stable state and ask the graph thread to make connections, schedule a

    // subsequent event to run cycle collection, which should not collect

    // panners that are still producing sound.

    SimpleTest.executeSoon(function() {

      SpecialPowers.forceGC();

      SpecialPowers.forceCC();

});

    break;

  case sourceDelayBufferCount:

    // Record this buffer during which PannerNode outputs were connected.

    for (var i = 0; i < 2; ++i) {

      e.inputBuffer.copyFromChannel(referenceOutput[i], i);

    e.target.onaudioprocess = null;

    e.target.disconnect();

    // If the buffer is silent, there is probably not much point just

    // increasing the buffer size, because, with the buffer size already

    // significantly larger than panner tail time, it demonstrates that the

    // lag between threads is much greater than the tail time.

    if (isChannelSilent(referenceOutput[0])) {

      todo(false, "Connections not detected.");

  referenceProcessCount++;

function onTestOutput(e) {

  if (testProcessCount < sourceDelayBufferCount + ccDelayBufferCount) {

    testProcessCount++;

    return;

  for (var i = 0; i < 2; ++i) {

    compareChannels(e.inputBuffer.getChannelData(i), referenceOutput[i]);

  e.target.onaudioprocess = null;

  e.target.disconnect();

  SimpleTest.finish();

function startTest() {

  // 0.002 is MaxDelayTimeSeconds in HRTFpanner.cpp

  // and 512 is fftSize() at 48 kHz.

  const expectedPannerTailTime = 0.002 * ctx.sampleRate + 512;

  // Place the listener to the side of the origin, where the panners are

  // positioned, to maximize delay in one ear.

  ctx.listener.setPosition(1,0,0);

  // Create some PannerNodes downstream from DelayNodes with delays long

  // enough for their source to finish, dispatch its "ended" event

  // and release its playing reference.  The DelayNodes should expire their

  // tail-time references before the PannerNodes and so only the PannerNode

  // lifetimes depends on their tail-time references.  Many DelayNodes are

  // created and timed to finish at different times so that one PannerNode

  // will be finishing the block processed immediately after the connect is

  // received.

  var source = ctx.createBufferSource();

  // Just short of blockSize here to avoid rounding into the next block

  var buffer = ctx.createBuffer(1, blockSize - 1, ctx.sampleRate);

  for (var i = 0; i < buffer.length; ++i) {

    buffer.getChannelData(0)[i] = Math.cos(Math.PI * i / buffer.length);

  source.buffer = buffer;

  source.start(0);

  source.onended = function() {

    gotEnded = true;

};

  // Time the first test panner to finish just before downstream DelayNodes

  // are about the be connected.  Note that DelayNode lifetime depends on

  // maxDelayTime so set that equal to the delay.

  var delayDuration =

    (sourceDelayBufferCount * bufferSize

     - expectedPannerTailTime - 2 * blockSize) / ctx.sampleRate;

  for (var i = 0; i < pannerCount; ++i) {

    var delay = ctx.createDelay(delayDuration);

    delay.delayTime.value = delayDuration;

    source.connect(delay);

    delay.connect(referencePanner)

    var panner = ctx.createPanner();

    panner.panningModel = "HRTF";

    delay.connect(panner);

    testPanners[i] = panner;

    delayDuration += blockSize / ctx.sampleRate;

  // Create a ScriptProcessor now to use as a timer to trigger connection of

  // downstream nodes.  It will also be used to record reference output.

  var referenceProcessor = ctx.createScriptProcessor(bufferSize, 2, 0);

  referenceProcessor.onaudioprocess = onReferenceOutput;

  // Start audioprocess events before source delays are connected.

  referenceProcessor.connect(ctx.destination);

  // The test ScriptProcessor will record output of testPanners.

  // Create it now so that it is synchronized with the referenceProcessor.

  testProcessor = ctx.createScriptProcessor(bufferSize, 2, 0);

  testProcessor.onaudioprocess = onTestOutput;

  // Start audioprocess events before source delays are connected.

  testProcessor.connect(ctx.destination);

promiseHRTFReady(ctx.sampleRate).then(startTest);

</script>

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