Eirudo

A lightweight plugin to embed YouTube videos while keeping the correct aspect ratio — all with a simple shortcode.
<ul>
<li>Very simple shortcode. Use it in posts or widgets.</li>
<li>Uses the default YouTube iframe embed, but fully responsive.</li>
<li>Custom aspect ratio if you want a different video size.</li>
<li>Automatically centered, so your video always looks neat in your content.</li>
<li>Lazy load support to improve performance.</li>
<li>100% free — no ads, no trackers, no funny business.</li>
</ul>
<h3>Arbitrary section</h3>
<h3>A brief Markdown Example</h3>
Pros: 
1. Simple and lightweight — one shortcode per video 
2. Lazy load support 
3. Extra parameters available for advanced users
Cons: 
1. Designed for simple embeds only (no playlist support, one video per shortcode)

Simple YouTube Responsive

Perfect

You can add a line to your functions.php to make videos responsive if you're doing your own theme. However, if you're not, this plugin works beautifully and gives other options like lazy load, etc. 

If doing your own theme, add: add_theme_support( 'responsive-embeds' );

Works Beautifully

Easily embed responsive YouTube videos using a simple shortcode. Lazy load included.

Tubal

A really simple and very lightweight plugin to embed customized Youtube videos & playlists anywhere in your blog or website using wordpress shortcodes.
<h4>Documentation, live demos and support</h4>
All documentation and demos are located at the <a href="http://www.margenn.com/tubal/youtube_shortcode/" rel="nofollow ugc">plugin website</a>.
The plugin website is proudly powered by WordPress and nearly all posts show a live demo so you can check how Youtube videos behave under every scenario/configuration such as:
<ul>
<li>Window resizing (resize the browser window to check how “fluid” videos adapt to fit)</li>
<li>Mobile viewing (visit the website with your mobile and check how videos look)</li>
<li>RSS viewing (subscribe to the feed and check how videos look in your RSS reader)</li>
<li>Different parameters for the Youtube player</li>
</ul>
What’s more, I’ve added <a href="http://youtubesc.uservoice.com" rel="nofollow ugc">Uservoice feedback</a> so you can share your ideas and issues. I want to hear from you. You can also post comments on every article.
I’ve moved all documentation to a website because I think it’s great to have a real WordPress environment set up and running with a working version of the plugin (latest) and a live demo for every piece of documentation.
<h4>Features:</h4>
<ul>
<li>Supports all official YouTube player customization parameters and respects Youtube’s default values: <a href="http://code.google.com/intl/en/apis/youtube/player_parameters.html" title="Official documentation" rel="nofollow ugc">Youtube official documentation</a>. You can override any default value.</li>
<li>Supports TinyMCE editor button (1.7+ version) to make it easier for you to customize the Youtube video player (auto-inserts the shortcode).</li>
<li>Supports RSS readers, Mobile browsers and fluid/elastic layouts.</li>
<li>Supports automatic calculation of video height. Just set the Youtube player <code>width</code> and omit the <code>height</code> parameter in the shortcode. There’s no need to set a height manually to get the perfect height.</li>
<li>Supports automatic localization of Flash videos (“old embed code” only). This plugin detects the visitor’s preferred language to set the default language of the Youtube player UI & the video’s captions/subtitles (otherwise en_US would be set by default for every visitor).</li>
<li>Supports normal Youtube URLs, short Youtube URLs, embed Youtube URLs and Youtube’s video ID as value for <code>url</code> parameter.</li>
<li>Supports setting a different “title” attribute for each Youtube video (useful for SEO & Accessibility).</li>
<li>Supports both the deprecated Youtube AS2 Flash player and the new iframe player (AS3 Flash or HTML5). This plugin uses Youtube’s new embed code (iframe: AS3 or HTML5 player) by default but optionally you can use the deprecated AS2 player (Flash only). The new embed code (iframe) will take care of the environment capabilities. This way you know your video will work on most devices, including mobile devices (that have Adobe’s Flash 10.1 installed or support CSS, iframes and basic Javascript) and RSS readers.</li>
<li>Supports web browsers with no Javascript support or with Javascript disabled. If a web browser does not support Javascript or Javascript is disabled, Youtube’s new embed code will not work. In that case this plugin will try to show the Youtube video using Adobe’s Flash (If Flash is not installed or enabled, the plugin will show the user what to do).</li>
<li>Developer friendly: <code>wp-content</code> directory can be renamed or moved safely to a different location. For more info read <a href="https://codex.wordpress.org/Editing_wp-config.php#Moving_wp-content" rel="nofollow ugc">Moving wp-content</a></li>
<li>Tested on IE 6+, Firefox 2+, Opera 8+, Safari 3+, Chrome 5+, iOS & Android (Webkit mobile), Opera mobile, Firefox mobile (Fennec) and RSS readers (such as Google Reader and NetNewsWire).</li>
</ul>
<h4>Roadmap</h4>
In version 1.9 I’ll develop a settings page so that you can store configuration defaults for every Youtube video.
Support its development <a href="https://www.paypal.com/cgi-bin/webscr?cmd=_s-xclick&hosted_button_id=6W2TXS68W7A8Y" rel="nofollow ugc">donating a few bucks 🙂</a> (PayPal).
Plugin developed by Túbal Martín at <a href="http://www.margenn.com" rel="nofollow ugc">www.margenn.com</a>.

Youtube shortcode

Embed customized Youtube videos & playlists anywhere using shortcodes

Simple YouTube Responsive vs Youtube shortcode