Eirudo

<p>A lightweight plugin to embed YouTube videos while keeping the correct aspect ratio — all with a simple shortcode.</p>
<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>
<p>Pros:<br />
1. Simple and lightweight — one shortcode per video<br />
2. Lazy load support<br />
3. Extra parameters available for advanced users</p>
<p>Cons:<br />
1. Designed for simple embeds only (no playlist support, one video per shortcode)</p>


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.

Fens Liu

<p>Smartideo 是为 WordPress 添加对在线视频支持的一款插件（支持手机、平板等设备HTML5播放）。 目前支持YouTube、哔哩哔哩、腾讯视频、优酷、搜狐视频、56、华数等网站。</p>
<p>直接粘贴视频播放页完整的URL到编辑器（单独一行），就可以加载视频播放器。</p>
<h4>详细介绍</h4>
<p>https://7yper.com/3639</p>


Smartideo

Smartideo 是为 WordPress 添加对在线视频支持的一款插件（支持手机、平板等设备HTML5播放）。

Simple YouTube Responsive vs Smartideo