PCM Output To Receiver

[Bob1969 6]

Hi guys i am getting PCM output to my receiver, i don't see an option to passthrough the audio, i do have my settings set to 5.1. How do i get Emby to output the original surround audio .

[Bob1969 6]

to give more info, due to my receiver not handling  HDR, i have 3 outputs from my gfx card, one to my Samsung tv, Dell Monitor and Pioneer receiver.

It works fine when i use VLC and setting my receiver as the output and the audio to passthrough mode.

[softworkz 5065]

Windows or Xbox?

Normally, the app is decoding the surround sound and sending output as multichannel PCM - which is the highest quality format. Are you getting 2.0 or 5.1 PCM?

[Bob1969 6]

It does indeed have surround sound going to the receiver, I have not been using my surround set up for 18 months, i am now discovering the ideal option of passthrough has gone in this newer version.

Isn't passthrough the highest quality option and to let my expensive receiver do the decoding?

This is a nightmare as i cant tell what format is being received as there are many different surround formats. Emby used to have passthrough.

[pwhodges 2012]

The quality of decoding doesn't vary that much - it is the encoding step which needs more careful choice to get the best quality.  But frankly, these days there's little point in worrying about it.

Paul

[Bob1969 6]

2 minutes ago, pwhodges said:

The quality of decoding doesn't vary that much - it is the encoding step which needs more careful choice to get the best quality.  But frankly, these days there's little point in worrying about it.

Paul

Its quite poor that you are deciding for me what is acceptable and what isnt. Have you any scientific testing to back up this claim. Sound like b/s to me. 

[pwhodges 2012]

I am not deciding anything for you - just stating my understanding of how it is.

There are lots of double-blind tests published for ADCs and DACs; also for different methods of compression and the possible different bit rates.  But admittedly, I can't recall seeing one focussed on different implementations of the encoding or decoding processes in isolation.

Compression formats are defined in terms of what certain patterns in the stream represent in the output; the process of reconstructing the audio defined by a given stream (aka decoding) is fairly straightforward and well understood.  The analysis of audio to produce the compressed stream is much more complicated, and involves decisions which can be varied by designers with different views on the exact important of various psycho-acoustic cues, and the quality of the filtering which is a necessary part of the process can also vary - so there may be a difference is what gets encoded by different encoders.  But however the choices fell in encoding, the decoder will faithfully reproduce them.

Paul

[softworkz 5065]

4 hours ago, Bob1969 said:

It does indeed have surround sound going to the receiver, I have not been using my surround set up for 18 months, i am now discovering the ideal option of passthrough has gone in this newer version.

It hasn't gone. I was just asking about your use cases because everybody has learned in the past that passthrough is the best option - because it was like that indeed.

In earlier days, it wasn't possible to transport uncompressed multi-channel PCM audio over HDMI, so the only choices were: either compressed or just 2-channel audio.

When the audio in your media was compressed in a format that your receiver can decode, then it was obviously the best option to the reicver decode it, because the compressed signal could go through HDMI, while uncompressed couldn't, so it didn't make sense to let the player decode it in the first place.

But many videos have AAC encoded multi-channel audio and hardly any receiver can decode that, so the video player had to decode it. But then, in order to send it over HDMI, the player had to re-compress it as AC-3. And that's bad, even through people were often thinking that it would be a good thing when they are getting AC-3 audio in "passtrhough" mode - which it isn't. AC-3 highly compressed and much worse than AAC. 
Nowadays, where uncompressed multichannel PCM can be sent over HDMI, this is clearly the better way. 

 

4 hours ago, Bob1969 said:

Isn't passthrough the highest quality option and to let my expensive receiver do the decoding?

No.

The only cases where it makes sense (at the moment) are Atmos and DTS:X - but only because software implementations are incomplete due to the specs being kept private and not everything has been reverse-engineered yet. In these two cases, you better let your receiver or TV do the decoding.

But apart from those special cases, it is a misconception that receivers - no matter how expensive - would be better. It's the other way round: Hifi receivers are not computers. They are using discrete chips, asiscs or similar hardware implementations which don't have the same capabilities like a modern CPU which can do floating point operations at high precision with ease, while those hardware implementations always have to make compromises in their implementations. I cannot tell you how big the differences are practically, but what is very clear is that when the algorithms are known and you implement them both, in software and then for hardware, the hardware implementation can NEVER BE BETTER. The best possible achievement is to be equal - which is even rather unlikely. 

The important capabilities of a Hifi reeiver are rather in D/A conversion and all the analog circuits. On the digital side, there's nothing to be excited about in case of those receivers.

 

4 hours ago, Bob1969 said:

This is a nightmare as i cant tell what format is being received as there are many different surround formats. Emby used to have passthrough.

During playback, press the gear icon and choose "stats for nerds", this shows you exactly what you want to know.

Finally, passthrough is still there, but it shows only when an HDMI audio output is selected:

 

 

 

[NakedPirate 15]

BTW, passthrough doesn't mean pass-through in many cases and doesn't mean passthrough of the original format neither, if the format can't be passed through/bitstreamed.

I'd be interested in a case apart:
What would happen if an app like emby transcodes let's say AAC 5.1 into PCM 5.1:
Would a TV per HDMI/EARC still only send 2.0 (like with nearly all TV models and internal audio our days) or the real deal. I want to know if this is only a handshake thingy.

Did anyone try this?

Long story short, I was curious and tried, it does not work.
PCM x.1 Video files played internally on my TVs are still converted to DD and audio files are send as PCM 2.0.
Bleeding hell, drop dead, all you TV manufacturers!
 

Edited November 10, 2025 by NakedPirate
I am Batman

[softworkz 5065]

6 hours ago, NakedPirate said:

What would happen if an app like emby transcodes let's say AAC 5.1 into PCM 5.1:
Would a TV per HDMI/EARC still only send 2.0 (like with nearly all TV models and internal audio our days) or the real deal. I want to know if this is only a handshake thingy.

Technically, that's more a decode than a transcode, because PCM is "uncompressed".

Note that you may need to set up the HDMI output for multi-channel and explicity select this output in the Emby app. Also try selectinng 5.1 there explicitly and enabled "exclusive audio" device access.

If it stil doesn't work, please post the mpv log from an example playback where it doesn't work (Settings >> About >> Logs).

[Bob1969 6]

@softworkzmany thanks indeed for your very interesting post, i read it all however some of it was over my head.

Im using a gaming pc / htpc. As i mentioned the HDMI audio output is not there and as a result no passthrough options, see below.

[Lessaj 467]

What devices are available in the drop down? If the HDMI is there you can select it and that should enable the options to appear.

[softworkz 5065]

6 minutes ago, Bob1969 said:

As i mentioned the HDMI audio output is not there

What do you mean by "not there"? What does the list show when opening?

Also, at Windows settings, what do you see when you clilck on "More  sound settings" 

in the playback list that you will see then?

When you rtight-click your hdmi output there, do you see a "Configure Speakers" item?

Also, double-click and show the 1s and 2nd tab pages. 

[Bob1969 6]

@LessajIs spot on i need to select a device to get the passthrough options, now its working fine and my receiver is displaying the correct surround formats . Having it set at default sound device means this setting is hidden.

[softworkz 5065]

7 minutes ago, Bob1969 said:

i need to select a device to get the passthrough options, now its working fine and my receiver is displaying the correct surround formats . Having it set at default sound device means this setting is hidden. 

 

Which is what I had said above already:

On 11/10/2025 at 1:55 AM, softworkz said:

Finally, passthrough is still there, but it shows only when an HDMI audio output is selected:

But I'm glad to hear that it's resolved for you!

Edited November 11, 2025 by softworkz

[Bob1969 6]

ah so you did i apologise for missing that part, thanks again for your help

[NakedPirate 15]

13 hours ago, softworkz said:

...snip....

If it stil doesn't work, please post the mpv log from an example playback where it doesn't work (Settings >> About >> Logs).
 

I shouldn't have hijacked the thread and mixed up different platforms, sorry...
I'm talking about the TV apps especially LG app. There are no "audio options for video playback" etc. settings.
And since I'm heading towards 60, getting lazy and modest, I liked the idea of just using my TV for everything, without 3rd party media players and stuff. 

What I learned the last weeks is that there's no way to tell my TVs to send multichannel PCM to my AVR, even it's a existing PCM without an app decoding it.
So I'm back to Raspberry and Shield.
Thanks!