Hi,There isnt any OOTB feature to automatically add caption to your
video, you need to add a parameter in viewer modifier in DM Component.
something like
below:&caption=//.vtt,1
//1 means Caption will be enabled at start of video, to disable make it
0However you can automate this process by overlaying DM component and by
adding modifier programmatically at runtime.Happy to helpRegards,Manish