Increased font sizes?

Not sure if this has been asked before but I’ve noticed that my posts that have videos (with Fitvid) have a slightly larger font size than other posts. It’s not too significant on Android devices but the fonts look huge on iOS devices.

With video http://i.imgur.com/h0dHDZx.png

Without video http://i.imgur.com/U5nq420.png

As you can see, the font is slightly larger with the video embedded into it. I have a responsive theme and use em (relative font sizes).

I couldn’t replicate the problem in my desktop browser but even checking through the font sizes in a reduced view, nothing looks out of place.

http://wordpress.org/extend/plugins/fitvids-for-wordpress/