Values.CaptionLanguageMappingSourceMaps a caption channel to an ISO 693-2 language code (http://www.loc.gov/standards/iso639-2), with an optional description.
type nonrec t = {captionChannel : int;The closed caption channel being described by this CaptionLanguageMapping. Each channel mapping must have a unique channel number (maximum of 4)
*)languageCode : string;Three character ISO 639-2 language code (see http://www.loc.gov/standards/iso639-2)
*)languageDescription : string;Textual description of language
*)}