FitVids.js is a lightweight, easy-to-use jQuery plugin for fluid width video embeds. FitVids automates the Intrinsic Ratio Method by Thierry Koblentz to achieve fluid width videos in your responsive web design.

Have a custom video player? They have a customSelector option where you can add your own specific video vendor selector too. FitVids.js is released under the WTFPL license.

Requirements: jQuery Framework
Demo: http://fitvidsjs.com/
License: WTFPL License