Subtitles for the hearing impaired (that are not technically closed cpations)

[JeannetteHo1]

I noticed that the Adaption Term "captions" has been deprecated and replaced by "closedCaptions" and "openCaptions" for the accessibilityFeature property.

I was wondering if we could use those terms with videos that contain subtitles for the hearing impaired (SDH). They serve the same function as closed captions, with descriptions of the settings, nonverbal sounds, etc. in addition to the dialogue of a film. However, they are not the same thing from a technical standpoint. The way they appear and the way they are technically encoded and transmitted differ from traditional closed captions. For instance, they appear like regular subtitles rather than white letters against a black background, even though their content is the same as what you would see in traditional closed captioning.

Sometimes they can be "turned off" and other times not. Would it be appropriate to apply "closedCaptions" and "openCaptions" to them as well? It is not clear from the way the documentation is written, and since cataloging librarians are starting to apply this vocabulary to describe videos with such features, I think this should be clarified.