Does Caldera output Atmos in Nvidia Shield?

Plex Labs
1

My testing with audio track in Atmos result in 5.1 (what I see in my Denon info screen) or 8 channel (what Caldera reports in signal path). Either way it is not outputting Atmos.

Plex client on the same Shield outputs Atmos during a movie.

Caldera 1.1.0.

2

I don’t think we output that, send logs so we can have a look.

3

I opened Caldera, played 2 - Atmos tracks and sent a debug log. Let me know if you need a way to ID the log to me.

4

Thanks for the log. Two things are going on.

First, Caldera can’t decode TrueHD, so your Plex server is transcoding these tracks to 8-channel Opus (512 kbps) before sending them. You still get all eight channels, but it’s a lossy copy of the TrueHD original, and the Atmos object information is dropped in the process.

Second, Caldera always decodes to PCM rather than passing a Dolby bitstream through to the receiver, so even with TrueHD support it would send 7.1 PCM, not Atmos. The Plex app gets Atmos for movies because it passes the bitstream through untouched.

Your log shows all eight channels leaving the app, so if the Denon reports 5.1, it’s worth checking the Shield’s surround sound settings.

5

Thanks for the explanation. Good to know how it processes Atmos music files. I’ve been hanging on to Kodi connected to my plex server to play Atmos music files, which it does handle properly.

Attempting to play Atmos files in Caldera is hit and miss (obviously since it is not supported). Clicking on a file has closed the app, froze the app, slowed the app. From time to time it will output the 7.1, like it is now (at this moment) for me.

Nice to Atmos output like Kodi, but I am glad that 5.1 and 7.1 are working! Thanks!

6

What about the Plex app on the Shield? If it sends Atmos for Movies, can you play FLAC Atmos mixes lossless?

7

Atmos positioning data isn’t available in FLAC. It’s Dolby Digital Plus (EAC3) for compressed, or TrueHD for uncompressed.

8

Unfortunately you can’t. It is less capable than Caldera when it comes to to surround audio.

Atmos m4a files and FLAC surround all are output as 2.0 PCM on Plex on the Nvidia Shield.

So, Caldera is a step in the right direction, a big step, just wish it would output Atmos like Kodi does so I can ditch Kodi.