This plugin makes your oEmbed responsive without JQuery using FluidVids script.

responsive-oembed.php

<?php
/**
 * Plugin Name: Responsive oEmbed
 * Plugin URI: https://foxnet-themes.fi
 * Description: This plugin makes your oEmbed responsive without JQuery using FluidVids script.
 * Version: 1.0.0
 * Author: Sami Keijonen
 * Author URI: http://foxnet.fi
 * Text Domain: responsive-oembed
 * Domain Path: /languages
 *
 * This program is free software; you can redistribute it and/or modify it under the terms of the GNU 
 * General Public License as published by the Free Software Foundation; either version 2 of the License, 
 * or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without 
 * even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
 *
 * You should have received a copy of the GNU General Public License along with this program; if not, write 
 * to the Free Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
 *
 * @package   Responsive oEmbed
 * @version   1.0.0
 * @since     1.0.0
 * @author    Sami Keijonen <[email protected]>
 * @copyright Copyright (c) 2014, Sami Keijonen
 * @link      https://foxnet-themes.fi
 * @license   http://www.gnu.org/licenses/old-licenses/gpl-2.0.html
 */

/* Exit if accessed directly. */
if ( ! defined( 'ABSPATH' ) ) exit;
 
final class Responsive_oEmbed {

	/**
	 * Plugin version, used for cache-busting of style and script file references.
	 *
	 * @since  1.0.0
	 * @var    string
	 */
	protected $plugin_version = '1.0.0';

	/**
	 * fluidvids version, used for cache-busting of script file references.
	 *
	 * @since  1.0.0
	 * @var    string
	 */
	protected $fluidvids_version = '2.4.1';

	/**
	 * Holds the instances of this class.
	 *
	 * @since  1.0.0
	 * @access private
	 * @var    object
	 */
	private static $instance;

	/**
	 * Plugin setup.
	 *
	 * @since  1.0.0
	 * @access public
	 * @return void
	 */
	public function __construct() {

		/* Set the constants needed by the plugin. */
		add_action( 'plugins_loaded', array( $this, 'constants' ), 1 );

		/* Internationalize the text strings used. */
		add_action( 'plugins_loaded', array( $this, 'i18n' ), 2 );

		/* Enqueue scripts and styles. */
		add_action( 'wp_enqueue_scripts', array( $this, 'enqueue_scripts' ) );
		
		/* Add JS when oembeds are around. */
		add_filter( 'wp_video_shortcode', array( $this, 'add_js_oembed' ) );
		add_filter( 'embed_oembed_html',  array( $this, 'add_js_oembed' ) );
		add_filter( 'video_embed_html',   array( $this, 'add_js_oembed' ) );
		
	}

	/**
	 * Defines constants used by the plugin.
	 *
	 * @since  1.0.0
	 * @access public
	 * @return void
	 */
	public static function constants() {

		/* Set constant path to the plugin directory. */
		define( 'ROV_DIR', trailingslashit( plugin_dir_path( __FILE__ ) ) );

		/* Set the constant path to the plugin directory URI. */
		define( 'ROV_URI', trailingslashit( plugin_dir_url( __FILE__ ) ) );
	}

	/**
	 * Loads the translation files.
	 *
	 * @since  1.0.0
	 * @access public
	 * @return void
	 */
	public static function i18n() {

		/* Load the translation of the plugin. */
		load_plugin_textdomain( 'responsive-oembed', false, 'responsive-oembed/languages' );
	}

	/**
	 * Loads the stylesheet for the plugin.
	 *
	 * @since  1.0.0
	 * @access public
	 * @return void
	 */
	public function enqueue_scripts() {

		/* Use the .min stylesheet if SCRIPT_DEBUG is turned off. */
		$suffix = ( defined( 'SCRIPT_DEBUG' ) && SCRIPT_DEBUG ) ? '' : '.min';
		
		/* Register the JS file. */
		wp_register_script( 'responsive-oembed', plugins_url( '/js/responsive-oembed.js', __FILE__ ), array(), $this->fluidvids_version, true );

	}
	
	/**
	 * Add JS when oembeds are around to make them responsive.
	 *
	 * @since  1.0.0
	 * @access public
	 * @return void
	 */
	function add_js_oembed( $html ) {
		
		/* Return if empty. */
		if ( empty( $html ) || ! is_string( $html ) ) {
			return $html;
		}
		
		/* Enqueue the JS file. */
		wp_enqueue_script( 'responsive-oembed' );
		
		/* Add JS in the footer. */
		add_action( 'wp_footer', array( $this, 'add_js_footer' ), 21 );
		
		/* Return html. */
		return $html;
		
	}
	
	/**
	 * Add JS in footer.
	 *
	 * @since  1.0.0
	 * @access public
	 * @return void
	 */
	function add_js_footer() { ?>
		
		<script>
		fluidvids.init({
			selector: ['embed', 'iframe', 'object'], // runs querySelectorAll()
			players: ['www.youtube.com', 'player.vimeo.com'] // players to support, not needed actually
		});
		</script>
		
		<?php
	}
	
	/**
	 * Returns the instance.
	 *
	 * @since  1.0.0
	 * @access public
	 * @return object
	 */
	public static function get_instance() {

		if ( !self::$instance )
			self::$instance = new self;

		return self::$instance;
	}
	
}

Responsive_oEmbed::get_instance();