Apple TV 4k, Infuse Pro m, no Dolby True HD and DTS on reciever


I use a Yamaha A6A receiver, Apple tv 4k and Infuse to stream from a NAS.
It has been working flawless, and suddenly no DD, DTS, DOLBY TRUE HD and DTS master audio on my reciever display.
Where is the problem ?
Is it because of some update to Apple tv, or is it infuse messing with me ?
my receiver keep showing PCM / AURO SURROUND and it didnt before.

Is PCM / AURO SURROUND, some sort of passthrough even though im pretty sure apple tv doesnt do that.
In newbie language : How much do i lose sound codec wise not having the true sound formats played back to the reciever ?
Or do i lose nothing with PCM/AURO SURROUND.
Its Just ■■■■■■■ annoying when most of movies i have on bluray and so on isnt Dolby Atmos :sob::face_with_peeking_eye:.
Is there a workaround or isnt there anything i can do ?

Best Regards

Infuse will decode the audio to PCM before sending it to receiver using the same proprietary Dolby/DTS algorithm your receiver uses (nothing lost). (“Auro Surround” is probably a surround mode to upconvert audio.) This is done because Apple TV doesn’t support full bitstream and can only bitstream lossy Dolby digital. PCM will be the best quality aside that you will lose 3D audio formats (DTS:X and Dolby TrueHD Atmos) as those are only supported via bitstream (not supported by Apple TV). You will not see any light on your receiver for these.

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More info on the audio options available when using Infuse on the Apple TV can be found in this guide.

Hey James.
Thx alot for taking ur time to write :heart:.
On my ATV 4k i cannot choose auto under sound, there is 2 options.
if i choose Atmos the other option is set to off and writes that signal non Atmos will be sent as LPCM.
If i choose on, Atmos is turned off and DD5.1 is active.

So my question :
I choose Atmos to get LPCM.
My Reciever (Yamaha RX-A6A) shows “only” PCM on the display, is this the same as LPCM ?

  1. Do i get the exact same sound as i would have gotten with passthrough Dolby True HD/DTSMA ?

Best Regards Nicolaj

LPCM and PCM are interchangeable. Which you see will depend on the receiver model.

As long as you have the Audio Format option set to Auto on the Apple TV, Infuse will always send the highest quality audio format possible.

If you want to test Atmos playback in Infuse a few compatible sample files can be found here.

Hope it’s ok to tack onto the end of this thread, I have a new LG C2, Sonos Beam Gen 2 and Apple TV 4K 2021.

If I play content from Disney+ etc the Sonos app tells me the sound profile being received is Dolby Atmos.

If I play content with TrueHD 7.1 via Infuse it comes through as Multichannel PCM 7.1 and sounds “flat” to say the least. For instance Top Gun Maverick, which if I play via the proper Apple TV app (I bought the film) it comes through as Atmos and sounds MUCH better.

I thought this limitation is on Apple, but if so, why does other apps sounds better and come through at Atmos, surely if it was a device limitation all apps would be affected? I LOVE Infuse but even through Plex the audio sounds better when it’s TrueHD 7.1 (probably cause it’s being transcoded) :frowning:

Atmos is a meta data extension to an existing audio container. Streaming services uses Dolby digital+ base with the atmos extension added on. Since Dolby digital+ is supported by apple you get atmos for this container on your receiver. TrueHD with atmos and dts-X are not supported therefore the atmos extension is ignored so only the base container is locally decided (TrueHD or DTSHD) and is sent to the receiver as PCM (bitstream not supported on AppleTV).


I fully understand now.
The real question, i cant do a side by side comparison. Is the PCM signal the “same” or is there a loss with getting PCM ?
Or said like this -
Side by side one streaming box with true hd or dtsma and the other pcm, which is best or is it a tie ?

It’s basically the same thing. The AppleTV is decoding the signal and sending the raw PCM to the receiver vs the receiver decoding the signal. There might be differences if your receiver does upconverting or any post processing.

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