LayoutTests/webaudio/stereopannernode-no-glitch.html - experimental/chromium/blink - Git at Google

 <!DOCTYPE html>
 <html>

 <head>
   <script src="../resources/js-test.js"></script>
   <script src="resources/compatibility.js"></script>
   <script src="resources/audio-testing.js"></script>
 </head>

 <body>
   <script>
     description('Test if StereoPannerNode producing glitches by crossing zero.');
     window.jsTestIsAsync = true;

     var audit = Audit.createTaskRunner();

     var sampleRate = 44100;

     // Note that this layout test requires rather large render duration because
     // we need enough time to do something useful in the |onstatechange| event
     // before rendering finishes.
     var renderDuration = 20;

     // The threshold for glitch detection. This was experimentally determined.
     var GLITCH_THRESHOLD = 0.0005;

     // The maximum threshold for the error between the actual and the expected
     // sample values. Experimentally determined.
     var MAX_ERROR_ALLOWED = 0.0000001;

     // Option for |Should| test util. The number of array elements to be printed
     // out is arbitrary.
     var SHOULD_OPTS = {
       numberOfArrayLog: 2
     };


     // Extract a transitional region from the AudioBuffer. If no transition
     // found, fail this test.
     function extractPanningTransition(input) {
       var chanL = input.getChannelData(0);
       var chanR = input.getChannelData(1);
       var start, end;
       var index = 1;

       // Find transition by comparing two consecutive samples. If two consecutive
       // samples are identical, the transition has not started.
       while (chanL[index-1] === chanL[index] || chanR[index-1] === chanR[index]) {
         if (++index >= input.length) {
           testFailed('No transition found in the channel data.');
           return null;
         }
       }
       start = index - 1;

       // Find the end of transition. If two consecutive samples are not equal,
       // the transition is still ongoing.
       while (chanL[index-1] !== chanL[index] || chanR[index-1] !== chanR[index]) {
         if (++index >= input.length) {
           testFailed('A transition found but the buffer ended prematurely.');
           return null;
         }
       }
       end = index;

       testPassed('Transition found. (length = ' + (end - start) + ')');

       return {
         left: chanL.subarray(start, end),
         right: chanR.subarray(start, end),
         length: end - start
       };
     }

     // JS implementation of stereo equal power panning.
     function panStereoEqualPower(pan, inputL, inputR) {
       pan = Math.min(1.0, Math.max(-1.0, pan));
       var output = [];
       var panRadian;
       if (!inputR) { // mono case.
         panRadian = (pan * 0.5 + 0.5) * Math.PI / 2;
         output[0] = inputL * Math.cos(panRadian);
         output[1] = inputR * Math.sin(panRadian);
       } else { // stereo case.
         panRadian = (pan <= 0 ? pan + 1 : pan) * Math.PI / 2;
         var gainL = Math.cos(panRadian);
         var gainR = Math.sin(panRadian);
         if (pan <= 0) {
           output[0] = inputL + inputR * gainL;
           output[1] = inputR * gainR;
         } else {
           output[0] = inputL * gainL;
           output[1] = inputR + inputL * gainR;
         }
       }
       return output;
     }

     // Generate the expected result of stereo equal panning. |input| is an
     // AudioBuffer to be panned.
     function generateStereoEqualPanningResult(input, startPan, endPan, length) {

       // Smoothing constant time is 0.05 second.
       var smoothingConstant = 1 - Math.exp(-1 / (sampleRate * 0.05));

       var inputL = input.getChannelData(0);
       var inputR = input.getChannelData(1);
       var pan = startPan;
       var outputL = [], outputR = [];

       for (var i = 0; i < length; i++) {
         var samples = panStereoEqualPower(pan, inputL[i], inputR[i]);
         outputL[i] = samples[0];
         outputR[i] = samples[1];
         pan += (endPan - pan) * smoothingConstant;
       }

       return {
         left: outputL,
         right: outputR
       };
     }


     function panAndVerify(options, done) {
       var context = new OfflineAudioContext(2, 44100 * renderDuration, 44100);
       var source = context.createBufferSource();
       var panner = context.createStereoPanner();
       var stereoBuffer = createConstantBuffer(context, 128, [1.0, 1.0]);

       source.buffer = stereoBuffer;
       source.loop = true;

       panner.pan.value = options.startPanValue;

       source.connect(panner);
       panner.connect(context.destination);
       source.start();

       context.onstatechange = function () {
         if (context.state === 'running')
           panner.pan.value = options.endPanValue;
       };

       context.startRendering().then(function (buffer) {
         var actual = extractPanningTransition(buffer);
         var expected = generateStereoEqualPanningResult(stereoBuffer,
           options.startPanValue, options.endPanValue, actual.length);

         // |notGlitch| tests are redundant if the actual and expected results
         // match and if the expected results themselves don't glitch.
         Should('Channel #0', actual.left).notGlitch(GLITCH_THRESHOLD);
         Should('Channel #1', actual.right).notGlitch(GLITCH_THRESHOLD);

         Should('Channel #0', actual.left, SHOULD_OPTS)
           .beCloseToArray(expected.left, MAX_ERROR_ALLOWED);
         Should('Channel #1', actual.right, SHOULD_OPTS)
           .beCloseToArray(expected.right, MAX_ERROR_ALLOWED);
       }).then(done);
     }

     // Task: move pan from negative (-0.1) to positive (0.1) value to check if
     // there is a glitch during the transition. See crbug.com/470559.
     audit.defineTask('negative-to-positive', function (done) {
       panAndVerify({ startPanValue: -0.1, endPanValue: 0.1 }, done);
     });


     // Task: move pan from positive (0.1) to negative (-0.1) value to check if
     // there is a glitch during the transition.
     audit.defineTask('positive-to-negative', function (done) {
       panAndVerify({ startPanValue: 0.1, endPanValue: -0.1 }, done);
     });

     audit.defineTask('finish-test', function (done) {
       done();
       finishJSTest();
     });

     audit.runTasks(
       'negative-to-positive',
       'positive-to-negative',
       'finish-test'
     );

     successfullyParsed = true;
   </script>
 </body>

 </html>
	<!DOCTYPE html>
	<html>

	<head>
	<script src="../resources/js-test.js"></script>
	<script src="resources/compatibility.js"></script>
	<script src="resources/audio-testing.js"></script>
	</head>

	<body>
	<script>
	description('Test if StereoPannerNode producing glitches by crossing zero.');
	window.jsTestIsAsync = true;

	var audit = Audit.createTaskRunner();

	var sampleRate = 44100;

	// Note that this layout test requires rather large render duration because
	// we need enough time to do something useful in the \|onstatechange\| event
	// before rendering finishes.
	var renderDuration = 20;

	// The threshold for glitch detection. This was experimentally determined.
	var GLITCH_THRESHOLD = 0.0005;

	// The maximum threshold for the error between the actual and the expected
	// sample values. Experimentally determined.
	var MAX_ERROR_ALLOWED = 0.0000001;

	// Option for \|Should\| test util. The number of array elements to be printed
	// out is arbitrary.
	var SHOULD_OPTS = {
	numberOfArrayLog: 2
	};


	// Extract a transitional region from the AudioBuffer. If no transition
	// found, fail this test.
	function extractPanningTransition(input) {
	var chanL = input.getChannelData(0);
	var chanR = input.getChannelData(1);
	var start, end;
	var index = 1;

	// Find transition by comparing two consecutive samples. If two consecutive
	// samples are identical, the transition has not started.
	while (chanL[index-1] === chanL[index] \|\| chanR[index-1] === chanR[index]) {
	if (++index >= input.length) {
	testFailed('No transition found in the channel data.');
	return null;
	}
	}
	start = index - 1;

	// Find the end of transition. If two consecutive samples are not equal,
	// the transition is still ongoing.
	while (chanL[index-1] !== chanL[index] \|\| chanR[index-1] !== chanR[index]) {
	if (++index >= input.length) {
	testFailed('A transition found but the buffer ended prematurely.');
	return null;
	}
	}
	end = index;

	testPassed('Transition found. (length = ' + (end - start) + ')');

	return {
	left: chanL.subarray(start, end),
	right: chanR.subarray(start, end),
	length: end - start
	};
	}

	// JS implementation of stereo equal power panning.
	function panStereoEqualPower(pan, inputL, inputR) {
	pan = Math.min(1.0, Math.max(-1.0, pan));
	var output = [];
	var panRadian;
	if (!inputR) { // mono case.
	panRadian = (pan * 0.5 + 0.5) * Math.PI / 2;
	output[0] = inputL * Math.cos(panRadian);
	output[1] = inputR * Math.sin(panRadian);
	} else { // stereo case.
	panRadian = (pan <= 0 ? pan + 1 : pan) * Math.PI / 2;
	var gainL = Math.cos(panRadian);
	var gainR = Math.sin(panRadian);
	if (pan <= 0) {
	output[0] = inputL + inputR * gainL;
	output[1] = inputR * gainR;
	} else {
	output[0] = inputL * gainL;
	output[1] = inputR + inputL * gainR;
	}
	}
	return output;
	}

	// Generate the expected result of stereo equal panning. \|input\| is an
	// AudioBuffer to be panned.
	function generateStereoEqualPanningResult(input, startPan, endPan, length) {

	// Smoothing constant time is 0.05 second.
	var smoothingConstant = 1 - Math.exp(-1 / (sampleRate * 0.05));

	var inputL = input.getChannelData(0);
	var inputR = input.getChannelData(1);
	var pan = startPan;
	var outputL = [], outputR = [];

	for (var i = 0; i < length; i++) {
	var samples = panStereoEqualPower(pan, inputL[i], inputR[i]);
	outputL[i] = samples[0];
	outputR[i] = samples[1];
	pan += (endPan - pan) * smoothingConstant;
	}

	return {
	left: outputL,
	right: outputR
	};
	}


	function panAndVerify(options, done) {
	var context = new OfflineAudioContext(2, 44100 * renderDuration, 44100);
	var source = context.createBufferSource();
	var panner = context.createStereoPanner();
	var stereoBuffer = createConstantBuffer(context, 128, [1.0, 1.0]);

	source.buffer = stereoBuffer;
	source.loop = true;

	panner.pan.value = options.startPanValue;

	source.connect(panner);
	panner.connect(context.destination);
	source.start();

	context.onstatechange = function () {
	if (context.state === 'running')
	panner.pan.value = options.endPanValue;
	};

	context.startRendering().then(function (buffer) {
	var actual = extractPanningTransition(buffer);
	var expected = generateStereoEqualPanningResult(stereoBuffer,
	options.startPanValue, options.endPanValue, actual.length);

	// \|notGlitch\| tests are redundant if the actual and expected results
	// match and if the expected results themselves don't glitch.
	Should('Channel #0', actual.left).notGlitch(GLITCH_THRESHOLD);
	Should('Channel #1', actual.right).notGlitch(GLITCH_THRESHOLD);

	Should('Channel #0', actual.left, SHOULD_OPTS)
	.beCloseToArray(expected.left, MAX_ERROR_ALLOWED);
	Should('Channel #1', actual.right, SHOULD_OPTS)
	.beCloseToArray(expected.right, MAX_ERROR_ALLOWED);
	}).then(done);
	}

	// Task: move pan from negative (-0.1) to positive (0.1) value to check if
	// there is a glitch during the transition. See crbug.com/470559.
	audit.defineTask('negative-to-positive', function (done) {
	panAndVerify({ startPanValue: -0.1, endPanValue: 0.1 }, done);
	});


	// Task: move pan from positive (0.1) to negative (-0.1) value to check if
	// there is a glitch during the transition.
	audit.defineTask('positive-to-negative', function (done) {
	panAndVerify({ startPanValue: 0.1, endPanValue: -0.1 }, done);
	});

	audit.defineTask('finish-test', function (done) {
	done();
	finishJSTest();
	});

	audit.runTasks(
	'negative-to-positive',
	'positive-to-negative',
	'finish-test'
	);

	successfullyParsed = true;
	</script>
	</body>

	</html>