SOLVED: Transcoding Issue on Unraid with Nvidia card

[Grannus]

Hi,
I'm new to Jellyfin.  I have 10.8.12 installed on an UNRAID Server running 6.12.3.  I use Nvidia shield as the player running 0.15.12.  The TV is a 2019 Samsung with arc but not e-arc with audio being a full Sonos system (Arc, sub and two satellites).
On the Jellyfin shield app, EAC3 audio works well including Dolby Atomos.  I cannot get TrueHD or DTS to work on this setup (player error encountered).  Neither will direct play on the Sonos without e-arc which is absent in this setup so transcoding would be required I think.  
From what I've read, it seems like I should be able to transcode on the fly TrueHD and DTS to Dolby Digital 5.1.  I have played around with numerous settings but cannot get it to work.  

I've installed the Unraid driver from Nvidia and attempted to modify the Jellyfin container parameters to use the Nvidia video card, but I'm not sure I've done it correctly.  I've attached a log file of a failed playback and a screenshot of the container parameters.  I'm new to Unraid, Jellyfin etc, I have probably missed something trivial so don't assume I set up permissions correctly etc.  Thanks!

Server hardware is
AMD Ryzen 3800X
32GB RAM
ROG Crosshair VIII Hero Motherboard
Nvidia 2070 Video card

[TheDreadPirate]

Another user just struggled through this process and they wrote up a guide for it.

https://forum.jellyfin.org/t-gpu-transcoding-on-unraid

[Grannus]

Thanks for the quick reply.  I tried the terminal command docker exec -it jellyfin nvidia-smi and it comes back with statistics on my video card.  I also changed the Nvidia-Visible_Devices to all from my specific card numbers.  It didn't correct playback.  The terminal command also produces statistics in that case so I think both could work.  I think everything else listed I had previously done.

I suspect the issue is file permissions for the transcoding cache but I'm not sure.

[TheDreadPirate]

So what exactly is the problem you are having? It is transcoding the audio to stereo AAC? Do you have downmixing enabled in the Android TV app? Also, audio is always transcoded on the CPU. Only video is transcoded on the GPU, which it looks like it is doing, according to the log you attached.

[Grannus]

The issue is the files don't play if the audio is DTS or True HD.  I have audio output on the jellyfin Nvidia Shield app set to Direct.  If I set it to Downmix to stero the file will play but in stereo and I've looking for pcm 5 channel or equivalent. 

I've tried with bitstream dolby digital audio and bitstream dts audio enabled and not enabled.  Files cannot play under all these permutations.

Interestingly, I played a file with EAC3 audio via the web interface and the jellyfin dashboard reports it is being transcoded.  I changed the resolution down to 720p and I can see in the GPU statics app in unraid that the Nvidia video card is being used to transcode the video.

So the issue is just present when trying to transcode DTS and True HD.

[tmsrxzar]

nevermind

[Grannus]

Thanks for the replies.  I figured it out for my particular setup which has peculiarities with the Sonos and lack of TV e-arc.  In the Nvidia Shield Settings, you need to go into advanced sound settings and then choose available formats.  Deselecting the True HD and DTS-X and DTS radio buttons forced Jellyfin to transcode the audio.  I think the above Nvidia bug is applicable only if you have the decode ability for DTS which I lack.