Why PLEX trancodes ATMOS to DD+ and not to TrueHD

server-nvidia-shield

#1

Hi Guys,

When I see a movie with an Atmos track, PLEX transcodes the audio into Dolby Digital Plus. Why not in TrueHD? If I use the Windows App for Playing (self server), the AVR displays the TrueHD logo.

Can not Plex do it for the Shield TV?

Thx! :)


#2

The Shield is connected to the AVR through HDMI? Or you use HDMI Arc or optical output from the TV?
When you look at the Shield plex player overlay information, does it says: "audio: transcode" or audio: direct play"?
Can you post the output of the software mediainfo about this file?

Dolby Atmos is an object-based surround sound that is added over Dolby TrueHD or Dolby Digital+. If your recevier doesn't support atmos but support Dolby trueHD or dolby digital plus, it will ignore the atmos portion of it. I would be very surprised if plex transcode it to dolby digital plus. If transcoding is required, I think plex transocdes to AAC.

I have few movie with Dobly trueHD with Atmos. My receiver is trueHD capable but doesn't support Atmos. When I play this movie with my Shield, the Shield says audio: direct play and my receiver says Dolby TrueHD. My Shield is directly connected on my recevier through HDMI.


#3

The other possibility is the file has both DD+ & TrueHD tracks, worth
checking audio selection


#4

@Zock-Rob said:
PLEX transcodes the audio into Dolby Digital Plus. Why not in TrueHD?

Transcode to TrueHD? TrueHD is a lossless format so there would be no transcoding involved with that, DD+ is a lossy format...


#5

Hey! My AVR (Pioneer VSX 830) supports TrueHD, but Plex (Shield TV) transcode Atmos every time to DD+. The Overlay shows the transcoding info. The Shield is connected through HDMI. DTS-Master-HD and TrueHD without Atmos works fine.

Thx! And sorry for my bad English! :))


#6

I have a new insight. The problem only occurs with movies in uhd/4k. 1080p with Atmos runs perfectly.


#7

@Zock-Rob said:
I have a new insight. The problem only occurs with movies in uhd/4k. 1080p with Atmos runs perfectly.

  • Check your file, or post the media info of the file to can help you. Because have no sense.
  • BTW. Check your HT Pioneer firmware, just in case.
  • The HDMI wires are HDCP 2.0 /2.2 compliant?
  • Your have connected your shield to the right input? (some HDMI ports in some receivers only support HDCP 1.4)
  • Connection needs be from your Nvidia Shield to the correct HDMI input of your receiver, and your receiver correct output needs to be connected to the correct input on your TV.

If is just one 4K file the problem post the media info of that file.
Find in google: "MediaInfo" (without the quotes "") and install that handy program that gives you the info of the file that you need.

Example of mediainfo:

Video
ID : 1
Format : HEVC
Format/Info : High Efficiency Video Coding
Format profile : Main 10@L5.1@High
Codec ID : V_MPEGH/ISO/HEVC
Duration : 2 h 0 min
Bit rate : 52.8 Mb/s
Width : 3 840 pixels
Height : 2 160 pixels
Display aspect ratio : 16:9
Frame rate mode : Constant
Frame rate : 23.976 (24000/1001) FPS
Color space : YUV
Chroma subsampling : 4:2:0 (Type 2)
Bit depth : 10 bits
Bits/(Pixel*Frame) : 0.265
Stream size : 44.3 GiB (92%)
Writing library : ATEME Titan KFE 3.7.3 (4.7.3.1003)
Language : English
Default : Yes
Forced : No
Color range : Limited
Color primaries : BT.2020

Audio #1
ID : 2
Format : DTS
Format/Info : Digital Theater Systems
Format profile : X / MA / Core
Codec ID : A_DTS
Duration : 2 h 0 min
Bit rate mode : Variable / Variable / Constant
Bit rate : 3 840 kb/s / 3 840 kb/s / 1 509 kb/s
Channel(s) : Object Based / 8 channels / 6 channels
Channel positions : Object Based / Front: L C R, Side: L R, Back: L R, LFE / Front: L C R, Side: L R, LFE
Sampling rate : / 48.0 kHz / 48.0 kHz
Frame rate : 93.750 FPS (512 SPF)
Bit depth : / 24 bits / 24 bits
Compression mode : / Lossless / Lossy
Stream size : 3.24 GiB (7%)
Language : English
Default : Yes
Forced : No

Audio #2
ID : 3
Format : DTS
Format/Info : Digital Theater Systems
Codec ID : A_DTS
Duration : 2 h 0 min
Bit rate mode : Constant
Bit rate : 768 kb/s
Channel(s) : 6 channels
Channel positions : Front: L C R, Side: L R, LFE
Sampling rate : 48.0 kHz
Frame rate : 93.750 FPS (512 SPF)
Bit depth : 24 bits
Compression mode : Lossy
Stream size : 660 MiB (1%)
Language : Spanish
Default : No
Forced : No


#8

This and all other 4k-Movies are Blu ray remux

For example Wonder Woman:

Video
ID : 1
Format : HEVC
Format/Info : High Efficiency Video Coding
Format profile : Main 10@L5.1@High
Codec ID : V_MPEGH/ISO/HEVC
Duration : 2 h 21 min
Bit rate : 50.0 Mb/s
Width : 3 840 pixels
Height : 2 160 pixels
Display aspect ratio : 16:9
Frame rate mode : Constant
Frame rate : 23.976 (24000/1001) FPS
Color space : YUV
Chroma subsampling : 4:2:0 (Type 2)
Bit depth : 10 bits
Bits/(Pixel*Frame) : 0.251
Stream size : 49.3 GiB (84%)
Writing library : ATEME Titan File 3.8.3 (4.8.3.0)

Default : Yes
Forced : No
Color range : Limited
Color primaries : BT.2020
Transfer characteristics : SMPTE ST 2084
Matrix coefficients : BT.2020 non-constant
Mastering display color primar : R: x=0.680000 y=0.320000, G: x=0.265000 y=0.690000, B: x=0.150000 y=0.060000, White point: x=0.312700 y=0.329000
Mastering display luminance : min: 0.0050 cd/m2, max: 4000.0000 cd/m2
Maximum Content Light Level : 1721 cd/m2
Maximum Frame-Average Light Le : 379 cd/m2

Audio #1
ID : 2
Format : TrueHD
Format profile : TrueHD+Atmos / TrueHD
Codec ID : A_TRUEHD
Duration : 2 h 21 min
Bit rate mode : Variable
Bit rate : 4 197 kb/s
Maximum bit rate : 7 260 kb/s
Channel(s) : Object Based / 8 channels
Channel positions : Object Based / Front: L C R, Side: L R, Back: L R, LFE
Sampling rate : / 48.0 kHz
Frame rate : 1 200.000 FPS (40 SPF)
Compression mode : Lossless
Stream size : 4.14 GiB (7%)
Title : Deutsch TrueHD Atmos 7.1 NIMA4K
Language : German
Default : Yes
Forced : No

Audio #2
ID : 3
Format : AC-3
Format/Info : Audio Coding 3
Format settings, Endianness : Big
Codec ID : A_AC3
Duration : 2 h 21 min
Bit rate mode : Constant
Bit rate : 448 kb/s
Channel(s) : 6 channels
Channel positions : Front: L C R, Side: L R, LFE
Sampling rate : 48.0 kHz
Frame rate : 31.250 FPS (1536 SPF)
Bit depth : 16 bits
Compression mode : Lossy
Stream size : 453 MiB (1%)
Title : Deutsch Dolby Digital 5.1 NIMA4K
Language : German
Service kind : Complete Main
Default : No
Forced : No

Audio #3
ID : 4
Format : TrueHD
Format profile : TrueHD+Atmos / TrueHD
Codec ID : A_TRUEHD
Duration : 2 h 21 min
Bit rate mode : Variable
Bit rate : 4 279 kb/s
Maximum bit rate : 7 509 kb/s
Channel(s) : Object Based / 8 channels
Channel positions : Object Based / Front: L C R, Side: L R, Back: L R, LFE
Sampling rate : / 48.0 kHz
Frame rate : 1 200.000 FPS (40 SPF)
Compression mode : Lossless
Stream size : 4.22 GiB (7%)
Title : English TrueHD Atmos 7.1 NIMA4K
Language : English
Default : No
Forced : No

Audio #4
ID : 5
Format : AC-3
Format/Info : Audio Coding 3
Format settings, Endianness : Big
Codec ID : A_AC3
Duration : 2 h 21 min
Bit rate mode : Constant
Bit rate : 448 kb/s
Channel(s) : 6 channels
Channel positions : Front: L C R, Side: L R, LFE
Sampling rate : 48.0 kHz
Frame rate : 31.250 FPS (1536 SPF)
Bit depth : 16 bits
Compression mode : Lossy
Stream size : 453 MiB (1%)
Title : English Dolby Digital 5.1 NIMA4K
Language : English
Service kind : Complete Main
Default : No
Forced : No


#9

2nd example is Batman vs Superman. There is no transcoding to DD+, but the player crashes with the error, the connection to the server is too slow, when i choose Atmos track.

Video
ID : 1
Format : HEVC
Format/Info : High Efficiency Video Coding
Format profile : Main 10@L5.1@High
Codec ID : V_MPEGH/ISO/HEVC
Duration : 3 h 2 min
Bit rate : 54.4 Mb/s
Width : 3 840 pixels
Height : 2 160 pixels
Display aspect ratio : 16:9
Frame rate mode : Constant
Frame rate : 23.976 (24000/1001) FPS
Color space : YUV
Chroma subsampling : 4:2:0 (Type 2)
Bit depth : 10 bits
Bits/(Pixel*Frame) : 0.274
Stream size : 69.4 GiB (83%)
Title : complete
Writing library : ATEME Titan KFE 3.7.3 (4.7.3.1003)
Language : English
Default : No
Forced : No
Color range : Limited
Color primaries : BT.2020
Transfer characteristics : SMPTE ST 2084
Matrix coefficients : BT.2020 non-constant
Mastering display color primar : R: x=0.680000 y=0.320000, G: x=0.265000 y=0.690000, B: x=0.150000 y=0.060000, White point: x=0.312700 y=0.329000
Mastering display luminance : min: 0.0050 cd/m2, max: 4000.0000 cd/m2
Maximum Content Light Level : 4000 cd/m2
Maximum Frame-Average Light Le : 1000 cd/m2

Audio #1
ID : 2
Format : AC-3
Format/Info : Audio Coding 3
Format settings, Endianness : Big
Codec ID : A_AC3
Duration : 3 h 2 min
Bit rate mode : Constant
Bit rate : 448 kb/s
Channel(s) : 6 channels
Channel positions : Front: L C R, Side: L R, LFE
Sampling rate : 48.0 kHz
Frame rate : 31.250 FPS (1536 SPF)
Bit depth : 16 bits
Compression mode : Lossy
Stream size : 585 MiB (1%)
Language : German
Service kind : Complete Main
Default : Yes
Forced : No

Audio #2
ID : 3
Format : TrueHD
Format profile : TrueHD+Atmos / TrueHD
Codec ID : A_TRUEHD
Duration : 3 h 2 min
Bit rate mode : Variable
Bit rate : 4 973 kb/s
Maximum bit rate : 8 046 kb/s
Channel(s) : Object Based / 8 channels
Channel positions : Object Based / Front: L C R, Side: L R, Back: L R, LFE
Sampling rate : / 48.0 kHz
Frame rate : 1 200.000 FPS (40 SPF)
Compression mode : Lossless
Stream size : 6.34 GiB (8%)
Language : German
Default : No
Forced : No

Audio #3
ID : 4
Format : AC-3
Format/Info : Audio Coding 3
Format settings, Endianness : Big
Codec ID : A_AC3
Duration : 3 h 2 min
Bit rate mode : Constant
Bit rate : 448 kb/s
Channel(s) : 6 channels
Channel positions : Front: L C R, Side: L R, LFE
Sampling rate : 48.0 kHz
Frame rate : 31.250 FPS (1536 SPF)
Bit depth : 16 bits
Compression mode : Lossy
Stream size : 585 MiB (1%)
Language : English
Service kind : Complete Main
Default : No
Forced : No

Audio #4
ID : 5
Format : TrueHD
Format profile : TrueHD+Atmos / TrueHD
Codec ID : A_TRUEHD
Duration : 3 h 2 min
Bit rate mode : Variable
Bit rate : 4 966 kb/s
Maximum bit rate : 8 199 kb/s
Channel(s) : Object Based / 8 channels
Channel positions : Object Based / Front: L C R, Side: L R, Back: L R, LFE
Sampling rate : / 48.0 kHz
Frame rate : 1 200.000 FPS (40 SPF)
Compression mode : Lossless
Stream size : 6.33 GiB (8%)
Language : English
Default : No
Forced : No


#10

- Check your file, or post the media info of the file to can help you. Because have no sense.

check!
- BTW. Check your HT Pioneer firmware, just in case
check!
- The HDMI wires are HDCP 2.0 /2.2 compliant?
2.2 check
- Your have connected your shield to the right input? (some HDMI ports in some receivers only support HDCP 1.4)
check


#11

@Zock-Rob said:
- Check your file, or post the media info of the file to can help you. Because have no sense.

check!
- BTW. Check your HT Pioneer firmware, just in case
check!
- The HDMI wires are HDCP 2.0 /2.2 compliant?
2.2 check
- Your have connected your shield to the right input? (some HDMI ports in some receivers only support HDCP 1.4)
check

I try that NIMA4K version that you have for wonder woman, then i change for a remux version. Anyway, it works fine. I have files that run at more than Bit rate 80 Mb/s and I have no problems. Batman v Superman I have the original 1:1 Bluray with a size of 92GB and I don't have any issue.

You server side, in settings--> advanced.... the transcoder is in auto? (BTW, what kind of server you are using? windows, mac, linux, nas, etc)

In your Shield TV you have in the settings the passthrough on?
You have to setup your Shield client to passthrought AUTO either.

Do you have your spdif audio out conected to your receiver? If yes. that's the problem, disconect the spdif OR choose HDMI for audio in HDMI port when your Shield Tv is connected.

Let me know


#12

All the settings are correct. Transcoder is auto, passthrought too. Plex itself is the server with external USB 3.0 drive, but i tested it on my HTPC (Win 10 x64) too, self problem. :/

If i use the HTPC as player, i have no problems, the problem must be the Shield TV. Hmmm :/

PS: No Spdif


#13

I’ve been having the same issue. Some files with ATMOS audio transcode to DD+ and some play perfectly fine. One thing I noticed the ones that don’t play correctly if I look at the xml data for the file in Plex, Plex doesn’t seem to be detecting a bitrate for theATMOS audio track. The ones that work the xml show an audio bitrate for the ATMOS track.


#14

Same Problem here with Shield and Denon X4300H. You will see if you play the Movie over Kodi it works perfectly. Still think it's a Plex Bug.


#15

I have the same issue but do not believe it is a Plex bug per se. I run two servers - one gives me the error, the other does not. In both cases, the same AVR is involved.

What I believe happens is that for one server, there is additional network traffic (content is not on the server itself, but on a NAS, whereas for the second server, the NAS itself runs the server and also has the content) which results is the bitrate not being optimally supported. The player is the same in both cases, nVidia Shield.

The NAS processor is much weaker than the CPU in the first server, so I don't believe it's a CPU issue, but a network issue.

Anyway, I believe that Plex then panics and claims the receiver does not support Atmos/TrueHD - I receive a message in that sense. It only happens with 4k files.

Sometimes it works if you play another non-4k file with TrueHD then you play the initial file again. Doesn't work always, though.

I have the luxury of switching to the other server, so it doesn't bother me too much. Still, should be fixed.


#16

I've had the same problem occur on the NAS as well for the first time. It was during some very intensive I/O operations - I also tried to play a 4k file at the same time, and got the transcode message due to the AVR not supporting HD audio.

So it's not a bug, but it is not handled and communicated properly to the user.


#17

FYI latest build 16.3.6 has fixed my TrueHD issues, files that would transcode now direct play great, however people are reporting lots of crashes and other issues.


#18

I'm having the same problem starting around 2 weeks ago.

-4K HDR Files are taking now lots of time to load
-Video will not be displayed in HDR on the tv
-Audio from Atmos gets modified to DD+
-In cases where i have 2 versions of the same movie (4k and 1080p 3D for example), if i select the 4K one, it would load and after some seconds switch to the 1080p version instead.

All these files up to 2 weeks ago were correctly playing, lunched smoothly, HDR + Atmos correctly processed.

I just looked around the forum and seems something similar is happening on Roku too after the recent update.

Update:

Today just out of curiosity i decided to try Emby, and all the mentioned files, are now playing correctly. This confirms to me the problem is in Plex on the Shield.
Unfortunately i am finding the interface and tagging methods of Emby a bit silly, and different from how i use it with Plex, so i would have to change a lot, plus is not free.. I really wanted to get my plex life subscription, but now i'm not sure anymore if this keeps on not working.


#19

I also have a lot of problems with 4k movies and their audio tracks, especially 7.1

A lot of them won't play if the 7.1 track is selected. Either the video freezes and the audio continues, the movie flat-out won't play, or it freezes every 5-10 seconds.

The video part of 4k doesn't seem to be the problem, it's the audio.

For instance, I'm trying to play Blade Runner 2049 in TrueHD. My receiver detects the 7.1 track, but after about 30 seconds the video freezes. Plex says it is transcoding 8channel (eac3).

If I disable passthrough, it won't play at all. Passthrough with auto doesn't work either. The same 4k movie will play totally fine if I select the 5.1 track though.

This leads me to believe there is some kind of issue with 4k with 7.1 audio tracks.


#20

@r4b1d said:
I'm having the same problem starting around 2 weeks ago.

-4K HDR Files are taking now lots of time to load
-Video will not be displayed in HDR on the tv
-Audio from Atmos gets modified to DD+
-In cases where i have 2 versions of the same movie (4k and 1080p 3D for example), if i select the 4K one, it would load and after some seconds switch to the 1080p version instead.

All these files up to 2 weeks ago were correctly playing, lunched smoothly, HDR + Atmos correctly processed.

I just looked around the forum and seems something similar is happening on Roku too after the recent update.

Update:

Today just out of curiosity i decided to try Emby, and all the mentioned files, are now playing correctly. This confirms to me the problem is in Plex on the Shield.
Unfortunately i am finding the interface and tagging methods of Emby a bit silly, and different from how i use it with Plex, so i would have to change a lot, plus is not free.. I really wanted to get my plex life subscription, but now i'm not sure anymore if this keeps on not working.

So after a couple of weeks of more searches and try, yesterday finally i was able to fix this (by pure coincidence).
Here is what i did:

-Move the 4K HDR files that are not working from the library's folder to another one
-Refresh the server, so that the files gets removed from your server
-Move back the files in your library's folder
-Refresh again the server to load the files back.

Doing this, fixed all my 4K HDR files, including the Atmos one which are now all working too.
No idea why this, but at least for me it solved those issues.