Scroll the background within a <div>

Scroll the background within a <div>

Hello,
I'm looking for a simple script to horizontally slide the background of a <div> (consisting of a single jpg) so that it starts from a position within the flow and then stops. (without any loop or second image). 
I've seen several slideshows with the "Ken Burns effect" (eg. www.slideshowify.com) but they are all structured as galleries, and most do the scaling of the jpg, compromising its quality.
I just need a simple horizontal "pan", without zoom.
Thank you all.