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<!DOCTYPE HTML>
<html>
<head>
<title>Test left/right symmetry and block-offset invariance of HRTF panner</title>
<script src="/tests/SimpleTest/SimpleTest.js"></script>
<script type="text/javascript" src="webaudio.js"></script>
<link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css" />
</head>
<body>
<pre id="test">
<script class="testbody" type="text/javascript">
SimpleTest.waitForExplicitFinish();
const blockSize = 128;
const bufferSize = 4096; // > HRTF panner latency
var ctx = new AudioContext();
function isChannelSilent(channel) {
for (var i = 0; i < channel.length; ++i) {
if (channel[i] != 0.0) {
return false;
}
}
return true;
}
function startTest() {
var leftPanner = ctx.createPanner();
var rightPanner = ctx.createPanner();
leftPanner.panningModel = "HRTF";
rightPanner.panningModel = "HRTF";
leftPanner.positionX.value = -1;
rightPanner.positionX.value = 1;
// Test that PannerNode processes the signal consistently irrespective of
// the offset in the processing block. This is done by inserting a delay of
// less than a block size before one panner.
const delayTime = 0.7 * blockSize / ctx.sampleRate;
var leftDelay = ctx.createDelay(delayTime);
leftDelay.delayTime.value = delayTime;
leftDelay.connect(leftPanner);
// and compensating for the delay after the other.
var rightDelay = ctx.createDelay(delayTime);
rightDelay.delayTime.value = delayTime;
rightPanner.connect(rightDelay);
// Feed the panners with a signal having some harmonics to fill the spectrum.
var oscillator = ctx.createOscillator();
oscillator.frequency.value = 110;
oscillator.type = "sawtooth";
oscillator.connect(leftDelay);
oscillator.connect(rightPanner);
oscillator.start(0);
// Switch the channels on one panner output, and it should match the other.
var splitter = ctx.createChannelSplitter();
leftPanner.connect(splitter);
var merger = ctx.createChannelMerger();
splitter.connect(merger, 0, 1);
splitter.connect(merger, 1, 0);
// Invert one signal so that mixing with the other will find the difference.
var gain = ctx.createGain();
gain.gain.value = -1.0;
merger.connect(gain);
var processor = ctx.createScriptProcessor(bufferSize, 2, 0);
gain.connect(processor);
rightDelay.connect(processor);
processor.onaudioprocess =
function(e) {
compareBuffers(e.inputBuffer,
ctx.createBuffer(2, bufferSize, ctx.sampleRate));
e.target.onaudioprocess = null;
SimpleTest.finish();
}
}
function prepareTest() {
// A PannerNode will produce no output until it has loaded its HRIR
// database. Wait for this to load before starting the test.
var processor = ctx.createScriptProcessor(bufferSize, 2, 0);
var panner = ctx.createPanner();
panner.panningModel = "HRTF";
panner.connect(processor);
var oscillator = ctx.createOscillator();
oscillator.connect(panner);
oscillator.start(0);
processor.onaudioprocess =
function(e) {
if (isChannelSilent(e.inputBuffer.getChannelData(0)))
return;
oscillator.stop(0);
panner.disconnect();
e.target.onaudioprocess = null;
startTest();
};
}
prepareTest();
</script>
</pre>
</body>
</html>