7 background-color: black;
11 <body onload="main()">
12 <div id="buttons"></div>
16 <td id="video_header"></td>
17 <td>Absolute Diff</td>
18 <td>Different Pixels</td>
21 <td><img src="blackwhite.png"></div>
22 <td><video autoplay></video></div>
23 <td><canvas id="diff"></canvas></td>
24 <td><canvas id="mask"></canvas></td>
32 document.getElementById('result').textContent = str;
36 function loadVideo(name) {
37 var videoElem = document.querySelector('video');
38 videoElem.src = 'blackwhite_' + name;
40 document.getElementById('video_header').textContent = name;
41 videoElem.addEventListener('ended', onVideoEnded);
44 function onVideoEnded(e) {
45 document.title = verifyVideo() ? 'ENDED' : 'FAILED';
48 function onVideoError(e) {
49 document.title = 'ERROR';
50 document.getElementById('diff').style.visibility = 'hidden';
51 document.getElementById('mask').style.visibility = 'hidden';
52 log('Error playing video: ' + e.target.error.code + '.');
56 // Programatically create buttons for each clip for manual testing.
57 var buttonsElem = document.getElementById('buttons');
59 function createButton(name) {
60 var buttonElem = document.createElement('button');
61 buttonElem.textContent = name;
62 buttonElem.addEventListener('click', function() {
65 buttonsElem.appendChild(buttonElem);
81 for (var i = 0; i < VIDEOS.length; ++i) {
82 createButton(VIDEOS[i]);
85 // Video event handlers.
86 var videoElem = document.querySelector('video');
87 videoElem.addEventListener('error', onVideoError);
89 // Check if a query parameter was provided for automated tests.
90 if (window.location.search.length > 1) {
91 loadVideo(window.location.search.substr(1));
93 // If we're not an automated test, compute some pretty diffs.
94 document.querySelector('video').addEventListener('ended',
99 function getCanvasPixels(canvas) {
101 return canvas.getContext('2d')
102 .getImageData(0, 0, canvas.width, canvas.height)
105 var message = 'ERROR: ' + e;
106 if (e.name == 'SecurityError') {
107 message += ' Couldn\'t get image pixels, try running with ' +
108 '--allow-file-access-from-files.';
114 function verifyVideo() {
115 var videoElem = document.querySelector('video');
116 var offscreen = document.createElement('canvas');
117 offscreen.width = videoElem.videoWidth;
118 offscreen.height = videoElem.videoHeight;
119 offscreen.getContext('2d')
120 .drawImage(videoElem, 0, 0, offscreen.width, offscreen.height);
122 videoData = getCanvasPixels(offscreen);
126 // Check the color of a givel pixel |x,y| in |imgData| against an
127 // expected value, |expected|, with up to |allowedError| difference.
128 function checkColor(imgData, x, y, stride, expected, allowedError) {
129 for (var i = 0; i < 3; ++i) {
130 if (Math.abs(imgData[(x + y * stride) * 4 + i] - expected) >
138 // Check one pixel in each quadrant (in the upper left, away from
139 // boundaries and the text, to avoid compression artifacts).
140 // Also allow a small error, for the same reason.
142 // TODO(mtomasz): Once code.google.com/p/libyuv/issues/detail?id=324 is
143 // fixed, the allowedError should be decreased to 1.
144 var allowedError = 2;
146 return checkColor(videoData, 30, 30, videoElem.videoWidth, 0xff,
148 checkColor(videoData, 150, 30, videoElem.videoWidth, 0x00,
150 checkColor(videoData, 30, 150, videoElem.videoWidth, 0x10,
152 checkColor(videoData, 150, 150, videoElem.videoWidth, 0xef,
156 // Compute a standard diff image, plus a high-contrast mask that shows
157 // each differing pixel more visibly.
158 function computeDiffs() {
159 var diffElem = document.getElementById('diff');
160 var maskElem = document.getElementById('mask');
161 var videoElem = document.querySelector('video');
162 var imgElem = document.querySelector('img');
164 var width = imgElem.width;
165 var height = imgElem.height;
167 if (videoElem.videoWidth != width || videoElem.videoHeight != height) {
168 log('ERROR: video dimensions don\'t match reference image ' +
173 // Make an offscreen canvas to dump reference image pixels into.
174 var offscreen = document.createElement('canvas');
175 offscreen.width = width;
176 offscreen.height = height;
178 offscreen.getContext('2d').drawImage(imgElem, 0, 0, width, height);
179 imgData = getCanvasPixels(offscreen);
183 // Scale and clear diff canvases.
184 diffElem.width = maskElem.width = width;
185 diffElem.height = maskElem.height = height;
186 var diffCtx = diffElem.getContext('2d');
187 var maskCtx = maskElem.getContext('2d');
188 maskCtx.clearRect(0, 0, width, height);
189 diffCtx.clearRect(0, 0, width, height);
191 // Copy video pixels into diff.
192 diffCtx.drawImage(videoElem, 0, 0, width, height);
194 var diffIData = diffCtx.getImageData(0, 0, width, height);
195 var diffData = diffIData.data;
196 var maskIData = maskCtx.getImageData(0, 0, width, height);
197 var maskData = maskIData.data;
199 // Make diffs and collect stats.
200 var meanSquaredError = 0;
201 for (var i = 0; i < imgData.length; i += 4) {
203 for (var j = 0; j < 3; ++j) {
204 diffData[i + j] = Math.abs(diffData[i + j] - imgData[i + j]);
205 meanSquaredError += diffData[i + j] * diffData[i + j];
206 if (diffData[i + j] != 0) {
207 difference += diffData[i + j];
210 if (difference > 0) {
211 if (difference <= 3) {
212 // If we're only off by a bit per channel or so, use darker red.
215 // Bright red to indicate a different pixel.
222 meanSquaredError /= width * height;
223 log('Mean squared error: ' + meanSquaredError);
224 diffCtx.putImageData(diffIData, 0, 0);
225 maskCtx.putImageData(maskIData, 0, 0);
226 document.getElementById('diff').style.visibility = 'visible';
227 document.getElementById('mask').style.visibility = 'visible';