Create thumbnail from video file via file input

Question

I am attempting to create a thumbnail preview from a video file (mp4,3gp) from a form input type='file'. Many have said that this can be done server side only. I find this hard to believe since I just recently came across this Fiddle using HTML5 Canvas and Javascript.

Thumbnail Fiddle

The only problem is this requires the video to be present and the user to click play before they click a button to capture the thumbnail. I am wondering if there is a way to get the same results without the player being present and user clicking the button. For example: User click on file upload and selects video file and then thumbnail is generated. Any help/thoughts are welcome!

Answer 1

Canvas.drawImage must be based on html content.

source

here is a simplier jsfiddle

//and code
function capture(){
    var canvas = document.getElementById('canvas');
    var video = document.getElementById('video');
    canvas.getContext('2d').drawImage(video, 0, 0, video.videoWidth, video.videoHeight);
}

The advantage of this solution is that you can select the thumbnail you want based on the time of the video.

Answer 2

Recently needed this so I wrote a function, to take in a video file and a desired timestamp, and return an image blob at that time of the video.

Sample Usage:

try {
    // get the frame at 1.5 seconds of the video file
    const cover = await getVideoCover(file, 1.5);
    // print out the result image blob
    console.log(cover);
} catch (ex) {
    console.log("ERROR: ", ex);
}

Function:

function getVideoCover(file, seekTo = 0.0) {
    console.log("getting video cover for file: ", file);
    return new Promise((resolve, reject) => {
        // load the file to a video player
        const videoPlayer = document.createElement('video');
        videoPlayer.setAttribute('src', URL.createObjectURL(file));
        videoPlayer.load();
        videoPlayer.addEventListener('error', (ex) => {
            reject("error when loading video file", ex);
        });
        // load metadata of the video to get video duration and dimensions
        videoPlayer.addEventListener('loadedmetadata', () => {
            // seek to user defined timestamp (in seconds) if possible
            if (videoPlayer.duration < seekTo) {
                reject("video is too short.");
                return;
            }
            // delay seeking or else 'seeked' event won't fire on Safari
            setTimeout(() => {
              videoPlayer.currentTime = seekTo;
            }, 200);
            // extract video thumbnail once seeking is complete
            videoPlayer.addEventListener('seeked', () => {
                console.log('video is now paused at %ss.', seekTo);
                // define a canvas to have the same dimension as the video
                const canvas = document.createElement("canvas");
                canvas.width = videoPlayer.videoWidth;
                canvas.height = videoPlayer.videoHeight;
                // draw the video frame to canvas
                const ctx = canvas.getContext("2d");
                ctx.drawImage(videoPlayer, 0, 0, canvas.width, canvas.height);
                // return the canvas image as a blob
                ctx.canvas.toBlob(
                    blob => {
                        resolve(blob);
                    },
                    "image/jpeg",
                    0.75 /* quality */
                );
            });
        });
    });
}

Answer 3

Recently needed this and did quite some testing and boiling it down to the bare minimum, see https://codepen.io/aertmann/pen/mAVaPx

There are some limitations where it works, but fairly good browser support currently: Chrome, Firefox, Safari, Opera, IE10, IE11, Android (Chrome), iOS Safari (10+).

 video.preload = 'metadata';
 video.src = url;
 // Load video in Safari / IE11
 video.muted = true;
 video.playsInline = true;
 video.play();

Answer 4

The easiest way to display a thumbnail is using the <video> tag itself.

<video src="http://www.w3schools.com/html/mov_bbb.mp4"></video>

Use #t in the URL, if you want the thumbnail of x seconds.

E.g.:

<video src="http://www.w3schools.com/html/mov_bbb.mp4#t=5"></video>

Make sure that it does not include any attributes like autoplay or controls and it should not have a source tag as a child element.

With a little bit of JavaScript, you may also be able to play the video, when the thumbnail has been clicked.

document.querySelector('video').addEventListener('click', (e) => {
  if (!e.target.controls) { // Proceed, if there are no controls
    e.target.src = e.target.src.replace(/#t=\d+/g, ''); // Remove the time, which is set in the URL
    e.target.play(); // Play the video
    e.target.controls = true; // Enable controls
  }
});

<video src="http://www.w3schools.com/html/mov_bbb.mp4#t=5"></video>

Answer 5

You can use this function that I've written. You just need to pass the video file to it as an argument. It will return the dataURL of the thumbnail(i.e image preview) of that video. You can modify the return type according to your need.

const generateVideoThumbnail = (file: File) => {
  return new Promise((resolve) => {
    const canvas = document.createElement("canvas");
    const video = document.createElement("video");

    // this is important
    video.autoplay = true;
    video.muted = true;
    video.src = URL.createObjectURL(file);

    video.onloadeddata = () => {
      let ctx = canvas.getContext("2d");

      canvas.width = video.videoWidth;
      canvas.height = video.videoHeight;

      ctx.drawImage(video, 0, 0, video.videoWidth, video.videoHeight);
      video.pause();
      return resolve(canvas.toDataURL("image/png"));
    };
  });
};

Please keep in mind that this is a async function. So make sure to use it accordingly.

For instance:

const handleFileUpload = async (e) => {
  const thumbnail =  await generateVideoThumbnail(e.target.files[0]);
  console.log(thumbnail)
}

Answer 6

With jQuery Lib you can use my code here. $video is a Video element.This function will return a string

function createPoster($video) {
    //here you can set anytime you want
    $video.currentTime = 5;
    var canvas = document.createElement("canvas");
    canvas.width = 350;
    canvas.height = 200;
    canvas.getContext("2d").drawImage($video, 0, 0, canvas.width, canvas.height);
    return canvas.toDataURL("image/jpeg");;
}

Example usage:

$video.setAttribute("poster", createPoster($video));

Answer 7

I recently stumbled on the same issue and here is how I got around it.

firstly it will be easier if you have the video as an HTML element, so you either have it in the HTML like this

<video src="http://www.w3schools.com/html/mov_bbb.mp4"></video>

or you take from the input and create an HTML element with it.

The trick is to set the start time in the video tag to the part you want to seek and have as your thumbnail, you can do this by adding #t=1.5 to the end of the video source.

<video src="http://www.w3schools.com/html/mov_bbb.mp4#t=1.5"></video>

where 1.5 is the time you want to seek and get a thumbnail of.

This, however, makes the video start playing from that section of the video so to avoid that we add an event listener on the video's play button(s) and have the video start from the beginning by setting video.currentTime = 0

const video = document.querySelector('video');

video.addEventListener('click', (e)=> {
video.currentTime = 0 ; 
video.play();
})