Q: How do you get closed captions from a video being streamed on an iPad to show on the tv

I'm using an Apple TV 2 and both the original iPad and an iPad Air 2. Close Captions show on the iPads (over a blank/black screen) but not on tv. How do you get it show on the tv when using AirPlay to view videos fromAPI IPad to a tv. This happens especially with videos in Safari.