We’ve recently been adding the VTT files alongside the MP4 files on our own platform and I was wondering if it were possible to set closed captions to play by default if the VTT file is present, rather than the user having to turn it on. I’m also checking in our LMS to see if I can do anything there, but thought I’d check with the source first.
Many thanks
Hi 
Welcome to the Box Community!
Currently, users need to manually toggle the CC button to enable captions during playback. Our video preview does not currently support an out-of-the-box setting to automatically enable closed captions when a video starts. Check out Enabling Subtitles/Closed Captions in Video Preview to learn more.
If you need closed captions or subtitles to play automatically for accessibility or user convenience, you may consider exploring
Regarding your inquiry, we’ll also take it as feedback. To help us shape the future of Box, you can share this idea on Box Pulse. By sharing users' ideas and feedback, you can help our Product Team better understand and address users’ needs.
Have a great day! 
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