customLanguageCode property
Specify the language for this audio output track. The service puts this language code into your output audio track when you set Language code control (AudioLanguageCodeControl) to Use configured (USE_CONFIGURED). The service also uses your specified custom language code when you set Language code control (AudioLanguageCodeControl) to Follow input (FOLLOW_INPUT), but your input file doesn't specify a language code. For all outputs, you can use an ISO 639-2 or ISO 639-3 code. For streaming outputs, you can also use any other code in the full RFC-5646 specification. Streaming outputs are those that are in one of the following output groups: CMAF, DASH ISO, Apple HLS, or Microsoft Smooth Streaming.
Implementation
final String? customLanguageCode;