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280 lines
8.8 KiB
JavaScript
280 lines
8.8 KiB
JavaScript
/**
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* jspsych-video-keyboard-response
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* Josh de Leeuw
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*
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* plugin for playing a video file and getting a keyboard response
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*
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* documentation: docs.jspsych.org
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*
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**/
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jsPsych.plugins["video-keyboard-response"] = (function() {
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var plugin = {};
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jsPsych.pluginAPI.registerPreload('video-keyboard-response', 'stimulus', 'video');
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plugin.info = {
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name: 'video-keyboard-response',
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description: '',
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parameters: {
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stimulus: {
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type: jsPsych.plugins.parameterType.VIDEO,
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pretty_name: 'Video',
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default: undefined,
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description: 'The video file to play.'
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},
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choices: {
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type: jsPsych.plugins.parameterType.KEY,
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pretty_name: 'Choices',
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array: true,
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default: jsPsych.ALL_KEYS,
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description: 'The keys the subject is allowed to press to respond to the stimulus.'
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},
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prompt: {
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type: jsPsych.plugins.parameterType.STRING,
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pretty_name: 'Prompt',
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default: null,
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description: 'Any content here will be displayed below the stimulus.'
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},
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width: {
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type: jsPsych.plugins.parameterType.INT,
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pretty_name: 'Width',
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default: '',
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description: 'The width of the video in pixels.'
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},
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height: {
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type: jsPsych.plugins.parameterType.INT,
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pretty_name: 'Height',
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default: '',
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description: 'The height of the video display in pixels.'
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},
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autoplay: {
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type: jsPsych.plugins.parameterType.BOOL,
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pretty_name: 'Autoplay',
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default: true,
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description: 'If true, the video will begin playing as soon as it has loaded.'
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},
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controls: {
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type: jsPsych.plugins.parameterType.BOOL,
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pretty_name: 'Controls',
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default: false,
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description: 'If true, the subject will be able to pause the video or move the playback to any point in the video.'
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},
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start: {
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type: jsPsych.plugins.parameterType.FLOAT,
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pretty_name: 'Start',
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default: null,
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description: 'Time to start the clip.'
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},
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stop: {
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type: jsPsych.plugins.parameterType.FLOAT,
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pretty_name: 'Stop',
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default: null,
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description: 'Time to stop the clip.'
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},
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rate: {
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type: jsPsych.plugins.parameterType.FLOAT,
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pretty_name: 'Rate',
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default: 1,
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description: 'The playback rate of the video. 1 is normal, <1 is slower, >1 is faster.'
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},
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trial_ends_after_video: {
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type: jsPsych.plugins.parameterType.BOOL,
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pretty_name: 'End trial after video finishes',
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default: false,
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description: 'If true, the trial will end immediately after the video finishes playing.'
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},
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trial_duration: {
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type: jsPsych.plugins.parameterType.INT,
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pretty_name: 'Trial duration',
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default: null,
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description: 'How long to show trial before it ends.'
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},
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response_ends_trial: {
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type: jsPsych.plugins.parameterType.BOOL,
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pretty_name: 'Response ends trial',
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default: true,
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description: 'If true, the trial will end when subject makes a response.'
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},
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response_allowed_while_playing: {
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type: jsPsych.plugins.parameterType.BOOL,
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pretty_name: 'Response allowed while playing',
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default: true,
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description: 'If true, then responses are allowed while the video is playing. '+
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'If false, then the video must finish playing before a response is accepted.'
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}
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}
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}
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plugin.trial = function(display_element, trial) {
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// setup stimulus
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var video_html = '<div>'
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video_html += '<video id="jspsych-video-keyboard-response-stimulus"';
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if(trial.width) {
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video_html += ' width="'+trial.width+'"';
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}
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if(trial.height) {
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video_html += ' height="'+trial.height+'"';
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}
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if(trial.autoplay & (trial.start == null)){
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// if autoplay is true and the start time is specified, then the video will start automatically
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// via the play() method, rather than the autoplay attribute, to prevent showing the first frame
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video_html += " autoplay ";
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}
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if(trial.controls){
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video_html +=" controls ";
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}
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if (trial.start !== null) {
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// hide video element when page loads if the start time is specified,
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// to prevent the video element from showing the first frame
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video_html += ' style="visibility: hidden;"';
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}
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video_html +=">";
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var video_preload_blob = jsPsych.pluginAPI.getVideoBuffer(trial.stimulus[0]);
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if(!video_preload_blob) {
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for(var i=0; i<trial.stimulus.length; i++){
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var file_name = trial.stimulus[i];
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if(file_name.indexOf('?') > -1){
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file_name = file_name.substring(0, file_name.indexOf('?'));
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}
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var type = file_name.substr(file_name.lastIndexOf('.') + 1);
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type = type.toLowerCase();
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if (type == "mov") {
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console.warn('Warning: video-keyboard-response plugin does not reliably support .mov files.')
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}
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video_html+='<source src="' + file_name + '" type="video/'+type+'">';
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}
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}
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video_html += "</video>";
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video_html += "</div>";
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// add prompt if there is one
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if (trial.prompt !== null) {
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video_html += trial.prompt;
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}
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display_element.innerHTML = video_html;
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var video_element = display_element.querySelector('#jspsych-video-keyboard-response-stimulus');
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if(video_preload_blob){
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video_element.src = video_preload_blob;
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}
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video_element.onended = function(){
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if(trial.trial_ends_after_video){
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end_trial();
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}
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if ((trial.response_allowed_while_playing == false) & (!trial.trial_ends_after_video)) {
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// start keyboard listener
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var keyboardListener = jsPsych.pluginAPI.getKeyboardResponse({
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callback_function: after_response,
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valid_responses: trial.choices,
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rt_method: 'performance',
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persist: false,
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allow_held_key: false,
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});
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}
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}
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video_element.playbackRate = trial.rate;
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// if video start time is specified, hide the video and set the starting time
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// before showing and playing, so that the video doesn't automatically show the first frame
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if(trial.start !== null){
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video_element.pause();
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video_element.currentTime = trial.start;
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video_element.onseeked = function() {
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video_element.style.visibility = "visible";
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if (trial.autoplay) {
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video_element.play();
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}
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}
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}
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if(trial.stop !== null){
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video_element.addEventListener('timeupdate', function(e){
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var currenttime = video_element.currentTime;
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if(currenttime >= trial.stop){
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video_element.pause();
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}
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})
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}
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// store response
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var response = {
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rt: null,
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key: null
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};
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// function to end trial when it is time
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function end_trial() {
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// kill any remaining setTimeout handlers
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jsPsych.pluginAPI.clearAllTimeouts();
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// kill keyboard listeners
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jsPsych.pluginAPI.cancelAllKeyboardResponses();
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// stop the video file if it is playing
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// remove end event listeners if they exist
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display_element.querySelector('#jspsych-video-keyboard-response-stimulus').pause();
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display_element.querySelector('#jspsych-video-keyboard-response-stimulus').onended = function(){ };
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// gather the data to store for the trial
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var trial_data = {
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rt: response.rt,
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stimulus: trial.stimulus,
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response: response.key
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};
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// clear the display
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display_element.innerHTML = '';
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// move on to the next trial
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jsPsych.finishTrial(trial_data);
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}
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// function to handle responses by the subject
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var after_response = function(info) {
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// after a valid response, the stimulus will have the CSS class 'responded'
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// which can be used to provide visual feedback that a response was recorded
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display_element.querySelector('#jspsych-video-keyboard-response-stimulus').className += ' responded';
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// only record the first response
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if (response.key == null) {
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response = info;
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}
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if (trial.response_ends_trial) {
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end_trial();
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}
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};
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// start the response listener
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if ((trial.choices != jsPsych.NO_KEYS) & (trial.response_allowed_while_playing)) {
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var keyboardListener = jsPsych.pluginAPI.getKeyboardResponse({
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callback_function: after_response,
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valid_responses: trial.choices,
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rt_method: 'performance',
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persist: false,
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allow_held_key: false,
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});
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}
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// end trial if time limit is set
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if (trial.trial_duration !== null) {
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jsPsych.pluginAPI.setTimeout(function() {
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end_trial();
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}, trial.trial_duration);
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}
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};
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return plugin;
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})();
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