Updating my 4/20 post.
From Felix @ LG Canada’s Email support - fantastically clear, and detailed response from them.
Thank you for reaching out to us about the TrueHD from your TV app to your connected AV receiver. LG OLED TVs, including the C4 series, don’t support Dolby TrueHD passthrough from internal apps (like Plex) over HDMI eARC. This is mainly due to hardware limitations in how the TV handles audio internally.
You can get TrueHD passthrough if you’re using an external HDMI device (like a Blu-ray player or streaming box) plugged into the TV or directly into your receiver, but unfortunately, audio from built-in apps doesn’t get the same treatment.
So, when you play something with TrueHD audio through the Plex app on webOS, the TV will transcode it to a supported format like Dolby Digital Plus before sending it out, which means you lose the full lossless audio quality.
We really appreciate your feedback, it’s been noted as a suggestion for future updates and improvements to our TVs. Thanks for your patience and understanding!
It’s unclear why the internal webOS PLEX app can passthrough DTS-MA lossless, but not TRUEHD - this should have nothing to do with processing, or bitrate as it’s just passing the bitstream over eARC. Considering externally connected HDMI sources are passed through over eARC, I don’t get the internal webOS limitation passthrough.
Perhaps this is an easy fix buy just updating the internal capabilities profile that is reported to the PLEX webOS client.
From my previous post:
Cannot direct play with protocol: https, codec:truehd. Not found in profile
Cannot direct stream with protocol: hls, codec:truehd. Not found in profile.
For those interested in having TRUEHD lossless passed through eARC with the webOS PLEX client, my suggestion is to write, or call requesting this feature.
It’s crazy that people invest in a TV with such outstanding visual quality only to be let down by limitations on the audio side.
I want the best VIDEO, and the best AUDIO.
To LG’s credit - this is the ONLY complaint I have - lack of webOS TRUEHD passthrough.
Not too much else to fault.
The screen off feature is super awesome.
