third_party/WebKit/LayoutTests/webaudio/audiobuffersource-loop-grain-no-duration.html

   1 <!doctype html>
   2 <html>
   3   <head>
   4     <title>Test AudioBufferSourceNode looping without explicit duration</title>
   5     <script src="resources/compatibility.js"></script>
   6     <script src="resources/audio-testing.js"></script>
   7     <script src="../resources/js-test.js"></script>
   8   </head>
   9
  10   <body>
  11     <script>
  12       description("Test AudioBufferSourceNode looping without explicit duration");
  13
  14       var context;
  15       var buffer;
  16       var output;
  17       var expected;
  18       var sampleRate = 44100;
  19       var sourceFrames = 8;
  20       // How many loops of the source we want to render.  Any whole number greater than 1 will work.
  21       var loopCount = 4;
  22       var renderFrames = sourceFrames * loopCount;
  23
  24
  25       function checkResult(renderedBuffer) {
  26         var badIndex = -1;
  27         var success = true;
  28
  29         expected = buffer.getChannelData(0);
  30         output = renderedBuffer.getChannelData(0);
  31
  32         // Verify the output has the expected data.  The actual output should be a loopCount copies
  33         // of the source buffer.
  34         for (var k = 0; k < loopCount; ++k) {
  35           // Check that this current subset is a linear ramp matching the original source.
  36           for (var n = 0; n < sourceFrames; ++n) {
  37             if (expected[n] != output[n + k * sourceFrames]) {
  38               // Remember the first bad sample and exit all loops now.
  39               badIndex = n + k * sourceFrames;
  40               success = false;
  41               break;
  42             }
  43           }
  44           if (!success)
  45             break;
  46         }
  47
  48         if (success) {
  49           testPassed("Source looped correctly");
  50         } else {
  51           testFailed("First incorrect sample at index " + badIndex);
  52         }
  53       }
  54
  55       function runTest() {
  56         window.jsTestIsAsync = true;
  57
  58         // Create a short linear ramp and enable looping.  The test will verify that the ramp was
  59         // looped the appropriate number of times.
  60         context = new OfflineAudioContext(1, renderFrames, sampleRate);
  61         buffer = createLinearRampBuffer(context, sourceFrames);
  62         var source = context.createBufferSource();
  63         source.buffer = buffer;
  64         source.connect(context.destination);
  65
  66         // Loop the source, and start the source with an offset, but without a duration. In this
  67         // case, the source should loop "forever".  See crbug.com/457009.  The case where the
  68         // duration is given is covered in other tests.
  69         source.loop = true;
  70         source.start(0, 0);
  71         context.startRendering()
  72                .then(checkResult)
  73                .then(finishJSTest);
  74       }
  75
  76       runTest();
  77     </script>
  78   </body>
  79 </html>