Wordpress oEmbed Customizations

nh-oembed.php

<?php
/**
 * Clear oEmbed Cache on save
 * this is necessary in order to update the oembed output
 */
function nh_clear_oembed_caches($post_id) {
    if ( wp_is_post_revision( $post_id ) ) return;
    global $wp_embed;
    $wp_embed->delete_oembed_caches($post_id);
}
add_action('save_post', 'nh_clear_oembed_caches');

/**
 * Responsive oEmbed wrapper
 */
function nh_responsive_oembed( $output, $data, $url ) {
    if(!is_null($data->height) && !is_null($data->width)):
        $ratio = intval($data->height) / intval($data->width) * 100 .'%';
        $output = sprintf('<div class="video-embed">%s<span style="padding-bottom:%s" class="aspect-ratio"></span></div>', $output, $ratio);
    endif;
    return $output;
}
add_filter('oembed_dataparse', 'nh_responsive_oembed', 10, 3 );

/**
 * Modify embed dimensions
 * not necessary if using responsive oembed wrapper
 */
function custom_embed_size() {
  return array( 'width' => 600, 'height' => 999 );
}
add_filter( 'embed_defaults', 'custom_embed_size' );

/**
 * Remove related videos on YouTube oEmbed videos.
 */
 function nh_oembed_no_rel( $data, $url, $args ) {
    if ( strpos($data, 'youtube') !== FALSE ) {
        $data = str_replace('feature=oembed', 'feature=oembed&rel=0', $data);
    }
    return $data;
}
add_filter('oembed_result', 'nh_oembed_no_rel', 10, 3);

oEmbed responsive wrapper styling (scss):

.video-embed {
    margin: 20px 0;
    position: relative;

    .aspect-ratio {
        display: block;
        width: 100%;
        height: 0;
    }

    iframe {
        height: 100%;
        width: 100%;
        position: absolute;
        left: 0;
        top: 0;
    }
}