Lazy load your embedded media with Velocity – Connekt Media

Velocity is an alternative loading method to the standard to YouTube, Vimeo and SoundCloud iframe embeds. Decrease the loading time and increase the overall performance of your website by lazy loading media on-demand, not on initial page load.
How Velocity Works
Velocity works by replacing the default iframe provided by YouTube, Vimeo and SoundCloud with a custom media preview image. When a user clicks on the preview image the requested iframe is injected into the page and automatically begins to play for the user.
To add Velocity to your site, simply create a Velocity shortcode by selecting a preview image and media type using the intuitive shortcode builder then add the generated snippet to your page.
Examples
YouTube
[velocity type="youtube" id="2smWSF_NGWk" img="https://connekthq.com/wp-content/uploads/snooooooopdogg.jpg"; alt="Play Video" color="#000000" bkg_color="#FFFFFF"]
Vimeo
[velocity type="vimeo" id="22439234" img="https://connekthq.com/wp-content/uploads/mountain.jpg"; alt="Play Video" color="#FFFFFF" bkg_color="#000000"]
Screenshots
Velocity Settings Screen
Source: https://managewp.org/articles/13751/lazy-load-your-embedded-media-with-velocity-connekt-media

source https://williechiu40.wordpress.com/2016/11/02/lazy-load-your-embedded-media-with-velocity-connekt-media/