Make 50MB background video load faster on wordpress site

I'm trying to add a video to the background of a div that will autoplay on page load, but the size of the video is 50 MB. How can I optimize the video so that it loads faster? It's a Wordpress powered website.

I've added fast playback with video preload but it's not working as good.

<video id="video" preload="metadata" src="file.mp4" controls></video>

  video.addEventListener('loadedmetadata', function() {
    if (video.buffered.length === 0) return;

    var bufferedSeconds = video.buffered.end(0) - video.buffered.start(0);
    console.log(bufferedSeconds + ' seconds of video are ready to play!');