Writing a function to automatically add size and display options to YouTube vid?

I have a situation that I am a bit stumped on, on the home page I have an area where a YouTube clip can be added, it’s a video testimonial, but the size is limited to 300 width, I am wondering if there is a way to write a function to detect the video embed in that section and automatically add width, height, rel=0, and showinfo=0 to the player options.

Or is there possibly a better option to embed YouTube links on the page other than the WordPress default?

Thank you.