DTS:X being downmixed to 2 channels or not working at all

[krojew 2]

Hi,

I found a problem I can't seem to fix. I have movies in various audio formats, including DTS:X. With audio transcoding enabled, the channels sound like downmixed to simple stereo and I can see max audio channels = 2 in the transcoding logs. With transcoding disabled, playing DTS:X results in no audio at all. Is there a way to make DTS:X work? Emby version is 4.9.1.3. Transcoded info:

[visproduction 283]

Kro,

DTS-HD is normally handled as output through HDMI cable to an AV amp that supports DTS-HD.  From this amp it is then passed to whatever speaker system you have, which may or may not include the TV speakers.

Emby server media is delivered via Ethernet or sometimes just Wifi.  In these cases, there is no HDMI out.  I believe that DTS-HD surround needs HDMI to work.  So if media comes to your system without an HDMI, I believe it will just change to whatver your system allows which is most likely stereo.  Most nvidia hardware encoders offer HDMI output.  Apparently, they only support 5.1.  Maybe someone in the forum has a way to do DTS-HD with 7.1 with some hardware.

I looked here for info on nVidia : https://duckduckgo.com/?q=nvidia+hardware+video+decorder+HDMI+DTS-HD+7.1&ia=web

So, I believe the answer is based on how the video and audio is getting to your system.  5.1 may work via Ethernet but perhaps only audio AAC or Ac3 surround.  I don't know this answer, becuase I never do it.  Apparently DTS-HD requires a decoder AV processor that supports this surround sound and nvidia encoding hardware can output to HDMI and send surround sound that way.

I would guess that you do hear DTS-HD somehow.  Is it via a blu-ray player?  If true, then the blu-ray may decode the audio into surround and send that via HDMI.  If you have an AV amplifier, then it may support DTS-HD.  Maybe even a sound bar setup which gets HDMI cable input may support your surround sound 7.1.  I think they are all sending the audio via HDMI cable and either the blu-ray, sound bar or AV amp is licensed to handle DTS-HD.   I think having a connection that does include HDMI is what stops your surround.

I hope that makes sense.  Let's see if someone here knows more info on the DTS-HD.

Related post: https://emby.media/community/index.php?/topic/129002-dts-x/

 

 

[krojew 2]

@visproductionthe issue is strictly with Emby. When playing the same file via VLC, DTS:X is correctly sent to my soundbar and every channel works as expected. Emby has problems with either transcoding or passing the audio through. Also, this isn't a problem with the browser itself, since https://www2.iis.fraunhofer.de/AAC/multichannel.html works perfectly fine with 7.1 setup, which also doesn't work with Emby due to the reason given above.

[generiq 258]

Attach the mpv log from when the issue happens

[generiq 258]

7 hours ago, krojew said:

With transcoding disabled, playing DTS:X results in no audio at all.

Try that again and attach the mpv log

[krojew 2]

5 hours ago, generiq said:

Try that again and attach the mpv log

Which one is it?

[Luke 40106]

14 minutes ago, krojew said:

Which one is it?

All of the ones that were created or updated during the time of the playback in question. Thanks.

[krojew 2]

6 minutes ago, Luke said:

All of the ones that were created or updated during the time of the playback in question. Thanks.

Attached with and without audio transcoding.

ffmpeg-directstream-fabfec92-6458-43b7-a5c2-3714f67beec6_1.txt ffmpeg-remux-85c26a17-03da-44ef-bbca-073bd85107b1_1.txt

[generiq 258]

Those are the server logs. The mpv logs are from the app

[krojew 2]

4 minutes ago, generiq said:

Those are the server logs. The mpv logs are from the app

Can you tell me where to get those from?

[generiq 258]

17 minutes ago, krojew said:

Can you tell me where to get those from?

App settings > about > logs

Enable debug logging

Disable transcoding in the server, play file, attach log

[krojew 2]

1 minute ago, generiq said:

App settings > about > logs

Enable debug logging

Disable transcoding in the server, play file, attach log

There is no "about" in Emby settings. Are you by chance talking about a mobile app? I'm using a browser.

[generiq 258]

Of course it doesn't work. Browsers don't support that. You've posted in the wrong forum. This is the Windows app forum. Go get the app from the Windows store

[krojew 2]

Well, it's not true that browsers don't support that, since there's even a test that verifies it works, which my browser passed. But you're right that this is a wrong forum - can anyone move it to the right place? I don't seem to have that option.

[yocker 293]

38 minutes ago, krojew said:

Well, it's not true that browsers don't support that, since there's even a test that verifies it works, which my browser passed. But you're right that this is a wrong forum - can anyone move it to the right place? I don't seem to have that option.

As generiq said. Browsers do not support formats like DTS-MA, you will need a dedicated player for that.

[Luke 40106]

There is currently no browser that can direct play dts.

[visproduction 283]

On 7/3/2025 at 11:47 AM, krojew said:

@visproductionthe issue is strictly with Emby. When playing the same file via VLC, DTS:X is correctly sent to my soundbar and every channel works as expected. Emby has problems with either transcoding or passing the audio through. Also, this isn't a problem with the browser itself, since https://www2.iis.fraunhofer.de/AAC/multichannel.html works perfectly fine with 7.1 setup, which also doesn't work with Emby due to the reason given above.

Is your server connected to the TV or soundbar with HDMI cable?  Perhaps VLC is sending the media via HDMI, which may allow the surround sound to playback correctly.  Emby only uses HDMI cable if you have a hardware encoder like Nvidia Shield.  And again, apparently DTS:HD doesn't work currently with Nvidia and DTS-X only works when the AV Amp or Sound bar supports this and gets the incoming media via HDMI cable.

If you have an HDMI cable connection, try disconnecting it and see what VLC does then.

[krojew 2]

My PC, where I'm testing, is indeed connected to the soundbar with HDMI. Nevertheless, I think this topic can be closed since I migrated to Jellyfin.

[visproduction 283]

Kro,

Okay...  If you disconnect the HDMI cable, then the VLC playback probably will no longer be in surround DTS.  That would explain what is going on.  I think you need the audio DTS-X media to stream through HDMI to get your surround.  Emby only outputs through HDMI, if you have a hardware encoder.  It will not, as far as I know, push out through a server direct HDMI output port.  Emby streams using TCP packets over Ethernet or Wifi, except if you run it through a hardware board like Nvidia Shield.

Anyone, correct me if I got that wrong?

Are you able to playback your DTS-X in some other way, besides VLC through HDMI?

[yocker 293]

46 minutes ago, visproduction said:

Kro,

Okay...  If you disconnect the HDMI cable, then the VLC playback probably will no longer be in surround DTS.  That would explain what is going on.  I think you need the audio DTS-X media to stream through HDMI to get your surround.  Emby only outputs through HDMI, if you have a hardware encoder.  It will not, as far as I know, push out through a server direct HDMI output port.  Emby streams using TCP packets over Ethernet or Wifi, except if you run it through a hardware board like Nvidia Shield.

Anyone, correct me if I got that wrong?

Are you able to playback your DTS-X in some other way, besides VLC through HDMI?

You can kinda make it look like the browser supports DTS-MA.

Install the DTS program from the Microsoft store and enable it and that makes the PC support that format, this still requires HDMI.
This does however not make the browser support it, so it will have DTS-MA converted to something compatible and then Windows will then output that in DTS-MA after.

VLC will work because it supports passthrough with HDMI, this will simply pass on the audio to the actual speakers to be decoded there.
Browsers do not support audio passthrough.

DTS for headphones works without any HDMI but browsers still don't support it.

Afaik the only way to get DTS to work is using a dedicated program, that goes for Jellyfin too.
However.. Jellyfin might have an edge in transcoding DTS as the method in Emby (for me) just causes long stutters in the video no matter what device i use when transcoding.

[generiq 258]

The entire playback chain has to support it. Software and hardware. If any part of the chain doesn't,  you get nothing. That's why the server decaodes and resamples the audio. 

When using the store app, it uses mpv. mpv can do this natively. The server won't be involved. It can also bitstream the audio directly to the external audio device. This is why I wanted to see the mpv logs. That would tell me what's happening. 

He was comparing VLC to a browser. That was a mistake. 

If he used the Windows app, all of his dreams would come true.