EXTRA_ENCODINGS of ACTION_HDMI_AUDIO_PLUG intent of AudioManager reports EAC3 even when user has selected PCM only in Audio Output

[PratimMallick]

Using a TCL AndroidTV to play dolby digital stream(Ec3) and an external 5.1 is connected to the TV via HDMI ARC.

While deciding the AudioCapabilities we are reading the EXTRA_ENCODINGS of ACTION_HDMI_AUDIO_PLUG intent of audioManager. This reports the correct value of ENCODING_E_AC3 when Auto or Passthrough option is selected in the android tv's 'Digital Audio Out' user settings.
But when PCM is selected in this setting, the EXTRA_ENCODINGS still give a value of ENCODING_E_AC3 and maxChannelCount also comes to be 6 suggesting passthrough is possible.

Is this expected or a bug in Android framework? How does exoplayer detect the user setting correctly? Is there any Key that should be read by exoplayer?

[ojw28]

@andrewlewis - I don't really understand why this isn't just a duplicate of #7617 (if it is, please close it as such; thanks!).

[andrewlewis]

If I understand correctly, #7617 is actually about detecting optical plug events, while this issue is about AC3 output unexpectedly being reported as possible when the user overrides the encoded output setting to 'PCM only'.

Please could you check whether AC3 output actually works while in this PCM-only mode? It may be the case that the device supports transcoding AC3 down to PCM before sending it over HDMI.

[PratimMallick]

Yes @andrewlewis EC3 output works even if PCM-only mode is selected.