Sonos Arc soundbar DTS to AC3 Transcoding not working

[tylordurton]

I managed to crack the issue for my use-case, see the thread below

Plex says TrueHD not supported and transcodes video, even when speaker & media player supports it

Thanks @sixones, This is the strange thing as nothing has changed from a hardware perspective. The catalyst here is likely changing the shield audio to ‘selected’ removing DTS due to the Sonos Arc not being compatible. Sonos recently updated the Arc firmware to accept multi-channel PCM, this allows Plex to play DTS movies and accept the PMC sound. I think it was mentioned in the thread earlier that people did have issues when changing this option. I can absolutely confirm that the 8.9.0.21577 …

Basically it looks like a recent shield update upset the ‘handshake’ between the playback. After I reset the audio back to automatic and then back again to ‘selected’ everything started working.