I am looking for a program/browser extension that can generate closed captions on any video I watch online.

I like to watch a lot of YouTube tutorials, breaking news, and general information videos online but I can't always have the volume turned on because I'm at work. It would be nice to have closed captions be generated for those videos so I can know what they're saying.

It would be great if the closed captions were only a second or so behind what the person is saying (like on TV), but if there needs to be more of a delay for processing, that's fine too.