Sibin Grasic

Responsive Videos plugin will allow you to automatically resize and scale your embedded videos on mobile devices. 
CSS selector option is provided so you can target only your post / page content container.
Features
<ul>
<li>Automatic configuration option</li>
<li>Automatically resizes / scales all your embedded videos</li>
<li>Works on all browsers</li>
<li>Highly compatible – you can change the css selector for the text highlight</li>
<li>Customizable – you can select the page type on which to activate the fitVids script</li>
</ul>

Responsive videos – Fitvids

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Make your Embedded videos responsive on mobile devices with jQuery FitVids plugin

SaltTechno

The easiest & lightest WordPress plugin for fluid width video embeds. No extra settings required. Just install the plugin and enjoy responsive video embeds on your blog.
This plugin supports videos embedded from:
<ul>
<li>YouTube</li>
<li>Vimeo</li>
<li>Videopress</li>
<li>Vine</li>
<li>Blip.tv</li>
<li>Viddler</li>
<li>Kickstarter</li>
</ul>

Install FitVids – Embed fluid width Videos

The easiest & lightest WordPress plugin for fluid width video embeds. No extra settings required. Just install the plugin and enjoy responsive vid …

Responsive videos – Fitvids vs Install FitVids – Embed fluid width Videos