You have to check on the website that offers the video to see if they offer different formats. Some player like on YouTube for instance have a button on the media player to select the resolution. If the website offers only one (high resolution) format then you are out-of-luck. This is not something that Firefox can force.

Yeah.... I know some websites will let you change the quality. But a lot won't :-( I was hoping to find an add-on for this. No luck. I'm guessing it has something to do with protecting the content, it's not open source....

The best I've been able to come up with is a Java Script blocker.

Thanks though

Note that there is not much difference between normal unprotected content and DRM protected content. It might be easier to transcode content to multiple formats than with protected content where you first would have to remove the protection and then re-add it after re-encoding. DRM protected content is usually available in a higher quality because you usually need to pay for it to view.