third_party/WebKit/LayoutTests/webaudio/audiochannelmerger-disconnect.html

   1 <!DOCTYPE html>
   2 <html>
   3
   4 <head>
   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 ChannelMergerNode behavior on dynamic input change.');
  13     window.jsTestIsAsync = true;
  14
  15     var sampleRate = 44100;
  16     var numberOfChannels = 2;
  17
  18     // The test needs the long render length (20 seconds) to capture the
  19     // disconnection which happens after starting the rendering.
  20     var renderLength = sampleRate * 20;
  21
  22     var audit = Audit.createTaskRunner();
  23
  24     // Task: Check if the merger outputs a silent channel when an input is
  25     // disconnected.
  26     audit.defineTask('silent-disconnect', function (done) {
  27       var context = new OfflineAudioContext(
  28         numberOfChannels, renderLength, sampleRate
  29       );
  30       var merger = context.createChannelMerger();
  31       var source1 = context.createBufferSource();
  32       var source2 = context.createBufferSource();
  33
  34       // Create and assign a mono testing buffer.
  35       var bufferDCOffset = createTestingAudioBuffer(context, 1, renderLength);
  36       source1.buffer = bufferDCOffset;
  37       source2.buffer = bufferDCOffset;
  38
  39       // Connect the output of source into the 4th input of merger. The merger
  40       // should produce 6 channel output.
  41       source1.connect(merger, 0, 0);
  42       source2.connect(merger, 0, 1);
  43       merger.connect(context.destination);
  44       source1.start();
  45       source2.start();
  46
  47       // When the rendering begins, disconnect |source2| as soon as possible.
  48       context.onstatechange = function () {
  49         if (context.state === 'running')
  50           source2.disconnect();
  51       };
  52
  53       context.startRendering().then(function (buffer) {
  54
  55         // The entire first channel of the output should be 1.
  56         Should('Channel #0', buffer.getChannelData(0)).beConstantValueOf(1);
  57
  58         // The second channel should contain 1, and 0 after the disconnection.
  59         Should('Channel #1', buffer.getChannelData(1)).containValues([1, 0]);
  60
  61         done();
  62       });
  63     });
  64
  65     audit.defineTask('finish', function (done) {
  66       finishJSTest();
  67       done();
  68     });
  69
  70     audit.runTasks(
  71       'silent-disconnect',
  72       'finish'
  73     );
  74
  75     successfullyParsed = true;
  76   </script>
  77 </body>
  78
  79 </html>