Latest Apple TV 4K firmware and Windows 10 PMS.
Why does PMS convert 7.1 Dolby TruHD and DTS HD to Flac before sending it to the Apple TV 4K? I would prefer that it gets sent directly and unaltered to the Apple TV 4K so that it changes it to PCM. Is there any setting I can make on PMS so that it does this?
AppleTV limitation. It cannot passthrough TrueHD or dts audio.
FLAC and PCM are both lossless, so there should be no quality degradation from the conversion. However, Atmos and dts:X information will be lost in the conversion process.
The only off the shelf streaming device that supports passthrough of TrueHD, including Atmos, and dts/dts-HD/dts:X is the Nvidia Shield. If you acquire a Shield, purchase the Pro model. The non-Pro “tube” model has issues with high bit rate media such as 4K HDR movies with TrueHD and dts-HD audio.
I would prefer that PMS sends the signal unaltered to Apple TV and then let Apple TV decode it to PCM which should preserve the Atmos channels, true? Isn’t this what the Infuse player does?
As already stated by FordGuy61, this is a limitation of the Apple TV and not with Plex. If you want direct play of Atmos and DTS X then you need to get rid of your Apple TV and get a Nvidia Shield Pro.
No. Atmos will not be preserved.
The Infuse player can pass Dolby Digital Plus + Atmos, the version of Atmos used by streaming services.
The Infuse player cannot pass TrueHD nor TrueHD + Atmos, the version found on Blu-ray discs. Due to restrictions put in place by Apple, TrueHD is converted to PCM. The Atmos information is lost during the conversion process.
The Infuse player also converts dts/dts-HD/dts:X audio to PCM.
Additional information is available on the firecore website: Audio Options (tvOS) – Firecore Support
I’m not sure you’re quite understanding what acribb is asking for.
He’s asked why can’t PMS send the unaltered file directly to the Plex app (Direct Play) so that the AppleTV is the one transcoding the audio from TrueHD/Atmos over to PCM, instead of PMS.
Both Infuse and MrMC (Kodi) are fully able to do this. I’ve tested it myself on my AppleTV 4K, where I’ll test the exact same file coming from the exact same PMS, and right in the dashboard it says Direct Play for video/audio when playing in Infuse or MrMC… and yet when you load it up in the Plex app, it will Direct Stream the video and transcode the audio.
Yes, its true TrueHD/Atmos can’t be passed through on the AppleTV 4K currently… but no, that doesn’t mean PMS must transcode the audio, the AppleTV can do it itself. So this is indeed a limitation of Plex, as in the app on the AppleTV, considering Infuse/MrMC clearly don’t have this issue. This doesn’t solve the OPs root problem in the end, but it does indeed show a limitation of the Plex app.
See for yourself on the attached images -
Thank you for describing more clearly what I have been trying to communicate.
I too don’t understand why PMS has to first transcode to Flac before sending the Audio signal to Apple TV 4K. It’s a superfluous step.
I am taking a stab here but typically the Plex Clients will report the capabilities to PMS based on what the device is reporting for capabilities. Yes the AppleTV may be able to Transcode but the AppleTV is reporting that it can’t handle the format so this would be an issue with the AppleTV and not the Plex Client. I do not know anything about Infuse but Kodi is probably reporting that it can handle the format since it can transcode most formats already.
Eh, I think its odd to put blame on the AppleTV when its perfectly capable to handle transcoding client side with Infuse/MrMC. To me, that’s just an area Plex could improve on with their client.
Is the audio now being transcoded twice with PMS to the Plex client on Apple TV?
DTS HD / Dolby TruHD 7 channel → Flac → PCM at the Apple TV 4K → Plex client
Vs.
DTS HD / Dolby TruHD 7 channel → PCM at the Apple TV 4K → Infuse client
Still does not make any sense to me why Flac is in the middle when using the Plex client on the Apple TV 4K.
This topic was automatically closed 90 days after the last reply. New replies are no longer allowed.
