Why Apple TV suddenly requires manual handling of Audio Format?

LG TV runs on webOS and has apps for Netflix, Amazon Prime, etc.

I play same movies inside Apple TV 4K apps for Netflix, Amazon Prime, etc.

Mentioned LG TV apps for Netflix, Amazon Prime, etc. have no problem to stream both video and audio in the max format. JBL Soundbar 9.1 displays either "Dolby Atmos DD+" or "Dolby Surround DD" or "Dolby Surround DD+" accordingly. LG TV displays Dolby Atmos or HDR.

How come that LG TV apps can handle the same streaming content from the same source but Apple TV apps cannot without manual switching of audio format by disabling Dolby Atmos when the content does not provide one???

It is disgrace for Apple TV 4K device or tvOS platform to function worse than LG TV itself.

Apple TV 4K is connected to LG TV by "high speed HDMI with ethernet". Cable is tested for 4K Dolby Vision 60 Hz.

JBL Soundbar 9.1 is connected to HDMI ARC port.

Same path is used by both Apple TV 4K and LG TV.

Why is Apple TV 4K sending 5.1 content to JBL as PCM? JBL Soundbar 9.1 displays "PCM".

AN EXAMPLE:

Amazon Prime running on tvOS sends new TV series THE PERIPHERAL to JBL as "PCM".

Amazon Prime app running on LG TV webOS sends THE PERIPHERAL to JBL as "Dolby Surround DD+".

LG TV 65SM8500PLA

webOS TV Version 4.9.7-11 (goldilocks2-gyoen)

My configuration has no problem with playing Dolby Vision + Dolby Atmos content.

Whatever has Dolby Atmos, my JBL Soundbar 9.1 receives "Dolby Atmos DD+".

The problem is in the content without Dolby Atmos, usually it is marked as "5.1". This one Apple TV 4K sends as PCM. LG TV through his apps for Netflix, Amazon Prime, ... sends to JBL as Dolby Surround DD+.

You see the problem? Through the same hardware pipeline Apple TV 4K apps send PCM while LG TV apps send correct.

What is eARC and how is it different from ARC? | Sony AP (sony-asia.com)

Otherwise I understand the difference in bandwidth but this should not be the reason that Apple TV 4K apps require my manual change in Audio settings for every 5.1 content and then manual change back to Dolby Atmos. It's annoying that Apple's customer has to do something manully what LG TV software knows to do automatically.

Urquhart1244 wrote: If that model TV doesn’t have eARC, then you will have to see if you can connect differently. Possibly your soundbar allows video passthrough.

Why would you need "video passthrough" on my soundbar?

My JBL Soundbar 9.1 does not receive the video.

Hardware connection path is Apple TV 4K > HDMI > LG TV 65SM8500PLA > HDMI ARC > JBL Soundbar 9.1.

The only thing sent through between LG TV and JBL Soundbar is audio.

And I wrote above that this path is configured as Pass Through.

LG TV > SOUND OUT > HDMI ARC > Digital Sound Output = Pass Through

My LG TV 65SM8500PLA webOS obviously understands bandwidth limitation of HDMI ARC and compresses audio to Dolby Digital DD before sending it through HDMI ARC port to JBL Soundbar 9.1, right?

While Apple TV 4K sends uncompressed audio for every 5.1 content which LG TV according to my settings just passes through and JBL Soundbar 9.1 recognizes as PCM hence displaying "PCM" on its display.

LG TV > SOUND OUT > HDMI ARC > Digital Sound Output = Pass Through

JBL Soundbar 9.1 makes garbled audio out of PCM passed through from Apple TV 4K.

And this is the problem. Garbled audio for every 5.1 content sent by Apple TV 4K towards LG TV.

What puzzles me additionally is how the heck Apple TV 4K sends any Dolby Vision + Dolby Atmos to LG TV via HDMI port without ARC ?!? Whenever I am playing Dolby Vision + Dolby Atmos content with apps on Apple TV 4K, my LG TV displays info Dolby Vision in the upper right corner at the start of playing the content and my JBL Soundbar 9.1 displays "Dolby Atmos DD+" on its display. How can the data pass through regular HDMI port between Apple TV 4K and LG TV but 5.1 content has a problem to pass through via HDMI ARC port to JBL Soundbar 9.1 ? Just because Apple TV 4K device decides to send uncompressed audio for 5.1 content? What does it send when it is sending Dolby Atmos content ?!? Dolby Atmos requires more bandwidth than 5.1, correct?

Well, I did another test and that clarified things a lot.

I changed the connection by daisy linking Apple TV 4K to JBL Soundbar 9.1 HDMI IN port and then continued from JBL Soundbar 9.1 HDMI OUT port towards HDMI ARC port on LG TV.

This way Apple TV 4K allows only 4K HDR at 60Hz with Chroma 4:2:2 and no longer Dolby Vision.

But Apple TV 4K now sends DOLBY ATMOS MULTI-CH PCM to JBL Soundbar 9.1 which seems to be better than DOLBY ATMOS DD+ sent previously from LG TV towards JBL via HDMI ARC port.

Strange enough that under 4K HDR colors seem to be far more vibrant than under Dolby Vision. I really need to go and see what shall Dolby Vision bring better than 4K HDR?!?

When I go and run Apple TV app under webOS on my LG TV 65SM8500PLA then I get Dolby Vision on display but DOLBY ATMOS DD+ sent to JBL Soundbar 9.1.

Strange enough why OPTICAL connection between LG TV and JBL never works. I see the light in the cable but there is no error indication and JBL just remains silent no matter that volume level is adjustable. But this is another chapter in this troubleshooting.

Obviously you are right that missing HDMI eARC port is messing up with everything on my first hardware configuration and none of LG TV HDMI ARC port settings work fine. There are three possible: Pass Through, Auto or PCM. All three produce garbled sound on JBL Soundbar when sent from Apple TV 4K device and JBL always displays only "PCM" on its display. Of course LG TV in such configuration will never send DOLBY ATMOS MULTI-CH PCM but only DOLBY ATMOS DD+ for Dolby Atmos content or DOLBY SURROUND DD(+) for 5.1 content.

LG TV understands missing bandwidth due to only HDMI ARC and (if I understand correct) compresses the audio when its apps are in the game. What LG TV does to the audio coming from Apple TV 4K device in case of 5.1 content, I will never know, but what comes through JBL cannot reproduce into normal sound and it always detects as PCM only.

A. Is LG TV responsible to do something to the audio data on the way from Apple TV 4K towards JBL Soundbar 9.1?

B. Or it is JBL who does not understand Apple TV 4K's way of sending audio for 5.1 content?

Next TV with HDMI eARC! ****! Now I have to see how much do I lose when Apple TV 4K apps are streaming in comparison with when LG TV apps are streaming. Video versus audio quality - what is easier to accept being downgraded?

for Dolby Vision + Dolby Atmos content

in daisy chained configuration,

4K HDR Chroma 4:2:2

DOLBY ATMOS MULTI-CH PCM

in star topology,

Dolby Vision

DOLBY ATMOS DD+

for 5.1 content which is usually not Dolby Vision anyway

in star topology,

only garbled soound with JBL displaying "PCM"

in daisy chained configuration,

JBL still displays "PCM" when Apple TV 4K is streaming FRIENDS from HBO MAX but the sound is normal - not garbled :))) this is why I suspect LG TV has fingers in between when star topology is in place and Apple TV apps send audio data and LG TV apps send DOLBY SURROUND DD+ instead

.

LG TV > SOUND OUT > HDMI ARC > Digital Sound Output = Pass Through