Damon Damon - 3 months ago 138
Javascript Question

Dynamically using the first frame as poster in HTML5 video?

I'm wondering if there's any straightforward way to achieve this effect, without needing backend code to extract a frame, save it as a jpg and database it somewhere.

An effect whereby the first frame of the video just shows up as the poster when the video loads would be so helpful (it would only work if the browser can play back the video obviously, which might be a little different from how

poster
traditionally works, but that is not a concern.

Answer

There is a Popcorn.js plugin called Popcorn.capture which will allow you to create posters from any frame of your HTML5 video.

There is a limitation that is imposed by the browser that prohibits reading pixel data of resources requested across domains (using the canvas API to record the current value of a frame). The source video must be hosted on the same domain as the script and html page that is requesting it for this approach to work.

The code to create poster using this plugin is quite simple:

// This block of code must be run _after_ the DOM is ready
// This will capture the frame at the 10th second and create a poster
var video = Popcorn( "#video-id" );

// Once the video has loaded into memory, we can capture the poster
video.listen( "canplayall", function() {

  this.currentTime( 10 ).capture();

});
Comments