No subtitles in the YouTube web video player

[gwuen]

OS version: Arch Linux (rolling release)
Browser version: Firefox 139.0.4
Extension version: 0.3.1
Bridge version: 0.3.0

Description
When the extension is enabled and YouTube is whitelisted, subtitles don't show up. I can still change the subtitle language and as well as subtitle options (with a preview showing up on the screen), but the actual subtitles aren't visible. This happens without casting any media through the extension.

Steps to reproduce

1. Install the fx_cast extension
2. Add YouTube (https://www.youtube.com/*) to the site whitelist
3. Start playing any YouTube video with subtitles (e.g., https://youtu.be/dQw4w9WgXcQ)
4. Enable subtitles via the button or keyboard shortcut

Expected behaviour
Subtitles should be visible in the video.

Logs
I couldn't find any messages in the extension's or webpage's console log that seem to be related to this issue, but I'd be happy to provide full logs if anyone thinks they would be of help.

[MisterSirCode]

I believe this is not an fx_cast issue. Youtube's captions are running on the site, as far as I know, and are not embedded in the video stream.

Now, its possible the video stream may have subtitles, but that would likely require either the caster supporting it, or the TV rendering them- but I dont know if casted video footage even supports caption information

[gwuen]

@MisterSirCode I appreciate your input, but you totally missed my point. I don't mean subtitles as shown on the Chromecast or TV being cast to, but the subtitles shown in the YT web player in my browser. Also:

This happens without casting any media through the extension.

PS: If you really want to help, you can try to reproduce this bug and post your system information to rule out it's only my setup.