test_scriptProcessorNodeChannelCount.html

Enable keyboard shortcuts

<!DOCTYPE HTML>

<html>

<head>

  <title>Test AudioBufferSourceNode</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">

// We do not use our generic graph test framework here because

// the testing logic here is sort of complicated, and would

// not be easy to map to OfflineAudioContext, as ScriptProcessorNodes

// can experience delays.

SimpleTest.waitForExplicitFinish();

addLoadEvent(function() {

  var context = new AudioContext();

  var buffer = context.createBuffer(6, 2048, context.sampleRate);

  for (var i = 0; i < 2048; ++i) {

    for (var j = 0; j < 6; ++j) {

      buffer.getChannelData(0)[i] = Math.sin(440 * j * Math.PI * i / context.sampleRate);

  var monoBuffer = context.createBuffer(1, 2048, context.sampleRate);

  for (var i = 0; i < 2048; ++i) {

    monoBuffer.getChannelData(0)[i] = 1;

  var source = context.createBufferSource();

  var sp = context.createScriptProcessor(2048, 3);

  expectException(function() { sp.channelCount = 2; },

                  DOMException.NOT_SUPPORTED_ERR);

  sp.channelCountMode = "explicit";

  expectException(function() { sp.channelCountMode = "max"; },

                  DOMException.NOT_SUPPORTED_ERR);

  expectException(function() { sp.channelCountMode = "clamped-max"; },

                  DOMException.NOT_SUPPORTED_ERR);

  sp.channelInterpretation = "discrete";

  source.start(0);

  source.buffer = buffer;

  source.connect(sp);

  sp.connect(context.destination);

  var monoSource = context.createBufferSource();

  monoSource.buffer = monoBuffer;

  monoSource.connect(sp);

  monoSource.start(2048 / context.sampleRate);

  sp.onaudioprocess = function(e) {

    is(e.inputBuffer.numberOfChannels, 3, "Should be correctly down-mixed to three channels");

    for (var i = 0; i < 3; ++i) {

      compareChannels(e.inputBuffer.getChannelData(i), buffer.getChannelData(i));

    // On the next iteration, we'll get a silence buffer

    sp.onaudioprocess = function(e) {

      var emptyBuffer = context.createBuffer(1, 2048, context.sampleRate);

      is(e.inputBuffer.numberOfChannels, 3, "Should be correctly up-mixed to three channels");

      compareChannels(e.inputBuffer.getChannelData(0), monoBuffer.getChannelData(0));

      for (var i = 1; i < 3; ++i) {

        compareChannels(e.inputBuffer.getChannelData(i), emptyBuffer.getChannelData(0));

      sp.onaudioprocess = null;

      sp.disconnect(context.destination);

      SimpleTest.finish();

};

};

});

</script>

</pre>

</body>

</html>