pub fn bcp47_language(iso639_2: &str) -> Option<String>Available on crate feature
std only.Expand description
Canonicalise an ISO 639-2 language code into a BCP 47 (RFC 5646) primary
language subtag, as required by RFC 8216bis EXT-X-MEDIA LANGUAGE.
HLS LANGUAGE must be an RFC 5646 (BCP 47) language tag; in BCP 47 the
primary subtag is the ISO 639-1 two-letter code when one exists, otherwise
the ISO 639-2/T (== ISO 639-3) three-letter code. ISO 639-2/B
bibliographic codes (fre, ger, dut, chi, …) are not valid BCP 47
subtags and are mapped to their terminology (T) equivalents first.
qaa..qtz (private use), und, mul, mis and zxx pass through
unchanged. Unknown or malformed codes return None.