Chris Rowley

Automatically adapt your embedded videos to the full width of their containers while maintaining the correct aspect ratio.
This is a simple filter that scans each embed in your posts, pages and custom post types, reads the width and height on the <code>iframe</code> and adds a style attribute including CSS <code>width</code>, <code>height</code> and <code>aspect-ratio</code> properties.
Currently supporting YouTube, Vimeo, WordPress/VideoPress and DailyMotion.

Easy Responsive Video

Easy Responsive Video adapts oEmbed video to full width while maintaining aspect ratio.

wistia

Wistia’s embed codes are designed to be very durable, but WordPress has a 
history of being particularly troublesome. This plugin adds oEmbed support so 
that pasting a link to the video’s page in Wistia will embed the video. The 
video’s URL must be by itself on its own line for this to work.
As of version 0.6 of this plugin, it is recommended that you check 
“Use oEmbed?” under Advanced Options when generating your embed code.
As of version 0.8 of this plugin, the legacy “Anti-Mangler” feature is an 
option that is turned off by default.
See the Wistia documentation for more: 
http://wistia.com/doc/wordpress#using_the_oembed_embed_code
<h3>Automatic Installation</h3>
<ol>
<li>In Admin Dashboard, go to Plugins > Add New.</li>
<li>Search for “Wistia WordPress Plugin”.</li>
<li>Find the plugin and click “Install”.</li>
</ol>
<h3>Manual Installation</h3>
<ol>
<li>Make a ‘wistia-wordpress-oembed-plugin’ directory in ‘/wp-content/plugins/’.</li>
<li>Upload all files in the repository to the 
‘/wp-content/plugins/wistia-wordpress-oembed-plugin/’ directory.</li>
<li>Activate the plugin through the ‘Plugins’ menu in WordPress.</li>
</ol>

Wistia WordPress Plugin

Enables all Wistia embed types to be used in your WordPress blog.

Easy Responsive Video vs Wistia WordPress Plugin