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A javascript library for thumbnailing images and videos on the client.
JavaScript CSS
Branch: master


Thumbnail all the things, client-side!


Live demo


var jsthumb = require("jsthumb")
  //When taking a screenshot from a video, it's best to supply the original dimensions of the video
  , screenshotOpts = {
      origWidth: 400
    , origHeight: 400
  //When resizing, you have to specify a maxWidth and maxHeight, and the original dimensions are recommended but optional
  , resizingOpts = {
      origWidth: 400
    , origHeight: 400
    , maxWidth:200
    , maxHeight:200
  //All these methods return a Base64 encoded string
  , videoThumbnail = jsthumb.screenshot(document.getElementById("my_video_tag"), screenshotOpts)
  , imageThumbnail = jsthumb.resize(document.getElementById("my_image_tag"), resizingOpts);

//You can also directly resize Base64 encoded data, but you'll need to provide a callback for that
jsthumb.resizeData(imageData, opts, function(err, base64Data) {
  //Do something with base64Data

//To load thumbnails in the browser
var myImage = new Image();
myImage.src = videoThumbnail;

Loading Media

It's not trivial figuring out when a video element is ready for thumbnailing. To remedy this problem, we provide a helper method that loads a video and fires a callback when it's ready for use.

var videoOpts = {
    sources: [
        src: "media/lego.mp4"
      , type: "video/mp4"
  , attributes: {
      //Required, must be unique for each element
      id: "example_video"

      // Optional, will resize video to fit parent element, maintaining aspect ratio
    , resize: true

//Appends the video to the body of the page
jsthumb.loadVideo(document.body, videoOpts, function (err, element, player, supported) {
  var video = $(element).find("video")[0];

  //This is the container div with all the Video.js controls
  ok(element, "Video container exists");

  //This is the actual video tag
  ok(video, "Video element exists");

  //This is the Video.js player
  ok(player, "Player exists");

  //This tells you whether or not thumbnailing is supported
  ok(supported, "Thumbnailing is available");

You can use .loadVideo to load the same video file multiple times on your page, just remember to set a different id attribute for each one.


HTML5 Video

JS-Thumb relies on the HTML5 <video> tag. Firefox and Opera at this time of writing do not support playing .mp4 videos with the <video> tag. If you use .loadVideo then these browsers will fall back to the flash player, which does not support thumbnailing.


Thumbnailing on iOS and Android devices is not supported at this time due to browser limitations. .loadVideo will still create a playable video, however.


We're broken on Travis-CI because PhantomJS does not yet support media like video and audio. If you have an idea of how to overcome this, I'm all ears!

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