Fire TV Edition TV platforms and sound bars outputting audio using the built in speakers (and not via an HDMI sink) do not have the above described ACTION_HDMI_AUDIO_PLUG boadcast action. In this case applications shall query the global setting external_surround_sound_enabled to verify if Dolby decoding is supported by the device.
https://developer.amazon.com/docs/fire-tv/dolby-integration-guidelines.html

