DeckLinkSubtitleKind type
Which subtitle format (if any) the SDI input is expected to carry.
A real SDI signal will usually carry at most one subtitle format; mixing OP47 teletext with SMPTE 334 CDP (CEA-708/608) is technically possible but rare and unsupported by Norsk. Configuring this explicitly means the input only advertises the subtitle context for the chosen format, so downstream consumers see a single, unambiguous subtitle stream.
Signature:
export type DeckLinkSubtitleKind = "none" | "teletext" | "cta708" | "cta608";