Firefox does not currently support captions or subtitles in the player window. This is because most sites have invented their own mechanisms for display captions or subtitles. YouTube's captions, for example, are implemented in a completely different way from Netflix's.

This makes it rather difficult for us as a browser to develop a general solution to the subtitles / caption problem.

Difficult, but not impossible. We're currently working on ways for us to develop site-specific behaviours for Picture-in-Picture. This allows Firefox's Picture-in-Picture feature to be smarter in how it interacts with specific video sites. In theory, this would allow us to detect the subtitles and captions and display them in the player window.

We're still working on getting those site-specific adapters working. After that, we will need to apply effort in order to detect, clone and react to captions and subtitles, for each popular video site.

So we're well aware that people want this feature. It's just more difficult to pull off than it might sound at first glance.

You can follow this bug if you'd like to know when captions and subtitles will work in Picture-in-Picture.

Do you have that option in Chrome? This sounds more like something you need to send to YouTube.

Firefox does not currently support captions or subtitles in the player window. This is because most sites have invented their own mechanisms for display captions or subtitles. YouTube's captions, for example, are implemented in a completely different way from Netflix's. This makes it rather difficult for us as a browser to develop a general solution to the subtitles / caption problem. Difficult, but not impossible. We're currently working on ways for us to develop site-specific behaviours for Picture-in-Picture. This allows Firefox's Picture-in-Picture feature to be smarter in how it interacts with specific video sites. In theory, this would allow us to detect the subtitles and captions and display them in the player window. We're still working on getting those site-specific adapters working. After that, we will need to apply effort in order to detect, clone and react to captions and subtitles, for each popular video site. So we're well aware that people want this feature. It's just more difficult to pull off than it might sound at first glance. You can follow this bug if you'd like to know when captions and subtitles will work in Picture-in-Picture.

thanks for the answer. do you need help in development? by the way i am a developer from last 10 years in majorly Microsoft technology. but can sure give this a try. is code for this open source?

Do you have that option in Chrome? This sounds more like something you need to send to YouTube.

Jon this feature is only available in Firefox browser. this is not in chrome. also YouTube is not providing this feature. this is browser based feature.

Ok, thanks for the info.

Yes, it's open source and commits are welcome. I'm not in a dev team, but you can ask them on bugzilla, what needs to be done.