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Add fps feature in video tracking #239

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Add fps feature in video tracking #239

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31 changes: 22 additions & 9 deletions src/tracking.js
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Original file line number Diff line number Diff line change
Expand Up @@ -223,11 +223,13 @@
* @param {object} opt_options Optional configuration to the tracker.
* @private
*/
tracking.trackVideo_ = function(element, tracker) {
tracking.trackVideo_ = function(element, tracker, opt_options) {
var canvas = document.createElement('canvas');
var context = canvas.getContext('2d');
var width;
var height;
var fps = opt_options.fps || 60;
var interval = 1000 / fps;


// FIXME here the video display size of the analysed size
Expand All @@ -246,16 +248,26 @@
// so in short, remove the tracking.TrackerTask from here
// if the user want to use it, it can create it himself
var requestId;
var prevTime;
var currTime;
var trackAnimationFrame_ = function() {
if (element.readyState === element.HAVE_ENOUGH_DATA) {
try {
// Firefox v~30.0 gets confused with the video readyState firing an
// erroneous HAVE_ENOUGH_DATA just before HAVE_CURRENT_DATA state,
// hence keep trying to read it until resolved.
context.drawImage(element, 0, 0, width, height);
} catch (err) {}
tracking.trackCanvasInternal_(canvas, tracker);
}
};
var requestAnimationFrame_ = function() {
requestId = window.requestAnimationFrame(function() {
if (element.readyState === element.HAVE_ENOUGH_DATA) {
try {
// Firefox v~30.0 gets confused with the video readyState firing an
// erroneous HAVE_ENOUGH_DATA just before HAVE_CURRENT_DATA state,
// hence keep trying to read it until resolved.
context.drawImage(element, 0, 0, width, height);
} catch (err) {}
tracking.trackCanvasInternal_(canvas, tracker);
currTime = Date.now();
var elapsedTime = currTime - prevTime;
if (elapsedTime > interval) {
prevTime = currTime - (elapsedTime % interval);
trackAnimationFrame_();
}
requestAnimationFrame_();
});
Expand All @@ -266,6 +278,7 @@
window.cancelAnimationFrame(requestId);
});
task.on('run', function() {
prevTime = Date.now();
requestAnimationFrame_();
});
return task.run();
Expand Down