Only 2.0 audio using HDMI passthrough

Plex Players Streaming Devices
1

Player Version#: 7.20
Hi.
I run Plex for Android TV on Mi Box S
The Mi Box is connected using HDMI.
Sound settings of the Android is set to auto and sound settings of Plex is set to HDMI passthrough. In this configuration my AV amplifier only receives 2.0 audio channels what ever is the audio source, 5.1, 7.1,…

Before the 7.2 release I had the same issue. But when I set the Plex audio settings to spdif passthrough, even if the Mi Box is only connected using HDMI, my AV amplifier received the right audio format.

I guess that something has been well corrected in the 7.2, regarding spdif, but this not solves the HDMI audio issue.

2

How are your devices connected?

Mi Box => AVR => TV

If so, then the passthrough will depend on what your Mi Box reports back to the Plex app of what it can output and then from your AVR on what it can accept.

If your connection is:

Mi Box => TV => AVR

Then a lot of what can happen will depend on your TV.

If you recreate this issue then provide the log from the Plex app, we can look to see what your devices report.

3

Thank you for your reply.

Devices are connected like this
Mi Box => TV => AVR
I use ARC protocol to send back the sound to the AVR.

I tried Kodi with Plex addons. When Kodi is set to audio passthrough, the AVR receives the right audio format (5.1 during my test)

Below beginning of Plex app log.
5

Your logs don’t show the info I’m looking for. Restart the Plex app, recreate the issue. Get me the entire log. I need to see the start of the app and the start of playback.

6

Sorry. Hope this one will be usefull.

7

Did you try playing something before you grabbed that log? I don’t see any playback attempts.

8

This one is full, I guess.

Plex-MiBoxS-2.log (121.0 KB)

9

set your Passthrough to Disabled or to Optical. If Optical, then deselect AC3 from the codec list.

1 Like
10

Ok, you have passthrough enabled in the app, but it looks like you have it disable on your TV.

08-28 08:46:45.938 i: [HdmiCaps] Capabilties changed (AudioCapabilities[maxChannelCount=2, supportedEncodings=[2, 5, 13]])

Plex only sees that stereo is supported so only stereo is sent to your TV. Check your TV’s audio settings.

11

I don’t think so. Like I said in my previous post, I use exactly the same settings on my TV and Mibox with Kodi and Plex plugins and everything is fine including DTS 5.1.

12

Perhaps, Kodi doesn’t care about the audio autodetection hdmi capabilities and only use what it has been set in the app.

13

Both settings do not work. I still have 2.0 audio channels.

14

I did it. I have only one audio setting on the OLED Panasonic TV which can be set to “Home Cinema”. This setting has to be use when you need ARC protocol. This is my case.
Each time the AVR is powered off before the TV this setting goes back to TV :frowning: I have to take care about the order I power on all devices…

So with the “Home cinema” setting. I can play AC3 5.1 and DTS 5.1 in direct play mode :slight_smile: But only AC3 5.1 it well recognised by the AVR, the DTS 5.1 or 7.1 is still view has channel 2.0 even if we are in Direct Play :face_with_raised_eyebrow:

Below log with playing AC3 5.1 and DTS 5.1 videos.
And as a reminder, I can play DTS 5.1 and 7.1 using Kodi and Plex plugins.

Plex-MiBoxS-3.log (128.4 KB)

15

That fits your log. Your TV reports it supports AC3 but not DTS so PMS has to transcode the DTS. Plex has to follow the hardware. Kodi does other stuff. Apple and orange situation so you can’t compare.

Edit - Sorry. I was wrong about that. The TV supports DTS for local playback but not passthrough, so it receives the DTS and decodes it locally to 2.0 then send that to the receiver.

In the Plex app settings, turn off support for DTS. This should cause PMS to transcode the 5.1 DTS to 5.1 AC3.

16

My goal is not to compare Kodi and Plex but to understand why Kodi is able to play all formats and not Plex using the same hardware

Are you sure ? Where can you see that in the log ? And Why my TV will transcode the DTS5.1 to Stereo when it’s sent by Plex app and not when it’s sent by Kodi app. In both case the HDMI signal should be the same, because none of one transcode the audio track. :face_with_monocle:

I can’t. This option is only available when you set Optical passthrough on Plex app. I’m currently on HDMI passthrough

17

Hello, any feedback ?

Thank you.

18

As a Plex Pass user, I’m clearly disappointed.
It seems that you are not able to give clear explanations and solution, so you definitively decide to stop to provide support ?
That’s not a professional behaviour.

19

Sorry, I did not get notified that you had responded. Not my intention to ignore your question.

Kodi does things differently. I don’t know the details, but Kodi appears to bypass any hardware limitations and does whatever they want. Plex relies on the hardware for passthrough.

I need to look into this. I thought this option should be available.

20

Sorry but this point is not clear.
Perhaps Kodi doesn’t take care about the hardware capabilities. But it shows that my configuration is able to play DTS audio track.
What’s ambiguous with Plex, Log information shows that PMS doesn’t transcode the Audio DTS track, but my AVR receives 2.0 audio track. You told me that this is my TV which does the transcoding. First I don’t understand why the TV does it for Plex and not for Kodi, in both case the audio track sending to the TV is the same. Second, I’m not sure that my TV is able to transcode video or audio formats.

21

Again, Is it possible to have support ?

THANK YOU