In newer WordPress version embed setting was removed from Dashboard. Ideally, it is controlled by WordPress settings. However, since setting has been removed there are few ways to achieve this:
1. Define width and height of embed content. Add following code at bottom of functions.php file
add_filter( 'embed_defaults', 'bigger_embed_size' );
function bigger_embed_size() {
return array( 'width' => 700, 'height' => 394 );
}This method has one limitation: in mobile view videos will appear taller.
2. Best way is using CSS class wrapper. Add following to style.css file before media queries
.videoWrapper {
position: relative;
padding-bottom: 56.25%; /* 16:9 */
padding-top: 25px;
height: 0;
}
.videoWrapper iframe {
position: absolute;
top: 0;
left: 0;
width: 100%;
height: 100%;
}and use following code format to embed youtube video code in the post
<div class="videoWrapper">
<!-- Copy & Pasted from YouTube -->
<iframe width="560" height="349" src="http://www.youtube.com/embed/n_dZNLr2cME?rel=0&hd=1" frameborder="0" allowfullscreen></iframe>
</div>This will display videos in proportional dimensions both on desktop and mobile. Limitation of this method: extra css code while embedding videos. (refer – https://css-tricks.com/NetMag/FluidWidthVideo/Article-FluidWidthVideo.php )
3. Use fitvids plugin or jquery method as shared here
https://css-tricks.com/NetMag/FluidWidthVideo/Article-FluidWidthVideo.php