Apple TV 4K - tvOS 18 breaks DD5.1 for some users.

[JeffPerrin]

i guess the only "problem" with this is that i've ripped all my BDs and 4kBDs with 5.1 audio since that's all i ever needed. so i'll have to redo all of those.

I would think a Blu-ray with HDMI out to an AVR would be pretty safe in terms of being backwards compatible with DD 5.1. (Assuming the disks are encoded to spec, of course.) It's when you start dealing with components driven by high-level, frequently-updated software such as with app-driven sound bars, streaming boxes (including the Apple TV), smart TVs, etc... that's when things can get dicey with the older formats and connectors.

 

[joeblough]

I would think a Blu-ray with HDMI out to an AVR would be pretty safe in terms of being backwards compatible with DD 5.1. (Assuming the disks are encoded to spec, of course.) It's when you start dealing with components driven by high-level, frequently-updated software such as with app-driven sound bars, streaming boxes (including the Apple TV), smart TVs, etc... that's when things can get dicey with the older formats and connectors.

oh yeah, i assume it will work fine, i just meant that i won't be taking advantage of the fancy audio formats the new AVR supports which i assume are present on those discs. some of the BD movies do deserve a re-encode though because back when i did some of them i only had a 1080 TV and so transcoded some to 720p to save space...

anyway i ordered a denon with 8k support so hopefully i'm set for a few years. last 2 AVRs were pioneers but there were some very angry reviews on pioneer's website having to do with early failures and bad customer service so i'm trying something new.

 

[joeblough]

I would think a Blu-ray with HDMI out to an AVR would be pretty safe in terms of being backwards compatible with DD 5.1. (Assuming the disks are encoded to spec, of course.) It's when you start dealing with components driven by high-level, frequently-updated software such as with app-driven sound bars, streaming boxes (including the Apple TV), smart TVs, etc... that's when things can get dicey with the older formats and connectors.

btw it's now in place. i just left everything connected to the TV and then connected the AVR from it's ARC hdmi to the television's eARC hdmi port. i used to have sporadic a/v sync problems with some TV broadcasts and that seems to be fixed. plus the ATV claims to be outputting atmos sound, though since i don't have atmos speakers (and only have 5.1) i'm not sure there's any advantage to that. need to do some reading.

prior to this with the pioneer connected via toslink getting the tv and receiver on the same page was a real PITA. i have a logitech harmony with a bunch of macros to configure everything, then added into homekit with homebridge. i have one of those tuo smart buttons that fires the macro to watch the appleTV, but then when the pioneer receiver would turn off due to power-saving, everything would go out of sync. with HDMI-CEC now the appleTV can just wake up the receiver. not sure how it wil go with my other devices which don't support HDMI-CEC but i guess we can turn the system on with the appleTV remote and then tell the TV to switch inputs.

so anyway, hopefully i'm future-proofed on sound now. thanks for the advice.

 

[JeffPerrin]

plus the ATV claims to be outputting atmos sound, though since i don't have atmos speakers (and only have 5.1) i'm not sure there's any advantage to that. need to do some reading.

Yes, it's just down mixing the Atmos for your 5.1 speakers. (Atmos is not restricted to systems with ceiling speakers.) When mixing for Atmos, producers have the ability to check for and adjust compatibility with a variety of speaker configurations.

Enjoy your new AVR! I have had a great experience with my Denon so far, four years on (knock on wood).

 

[priitv8]

…it's just down mixing the Atmos for your 5.1 speakers. (Atmos is not restricted to systems with ceiling speakers.)

Is it so? I think JOC encoder already downmixes everything into 5.1 and if the decoder knows Atmos, the ‘objects’ are removed from the 5.1 downmix and located at their proper coordinates during decoding and rendering.
This way no object audio gets lost in pre-atmos DD+ decoders, they just sound from the floor speakers.
Thus aTV only has to decode DD+ audio into PCM and can skip whole atmos processing (which will be missing in older decoders anyway). But no-one will miss any sound from the mix.

Dolby used to have a nice explanation of this processing on their developer website, but now it is gone from there.

 

[JeffPerrin]

I was generalizing the term "down mixing" in that, as you said, the Atmos content (including object sounds) will get re-mapped to the OP's 5.1 speakers via his new Atmos-compatible AVR.

In case anyone is wondering, the primary advantage of Dolby Atmos on a 5.1 speaker system is smoother panning of sounds which transition between the front and rear speakers. With a non-Atmos (channel-based) format, there can be a decibel "bump" in between the two speaker positions.

 

[priitv8]

I was generalizing the term "down mixing" in that, as you said, the Atmos content (including object sounds) will get re-mapped to the OP's 5.1 speakers via his new Atmos-compatible AVR.

Understood. Assuming the OP uses appleTV as his playback device, then the Dolby processing gets blurred between the apple and AVR.

 

[joeblough]

Understood. Assuming the OP uses appleTV as his playback device, then the Dolby processing gets blurred between the apple and AVR.

yes, using the appleTV. i wish there were better documentation about this. i ran into an issue last night where infuse was correctly selecting the 7.1 track from a 4kbd rip, but the receiver was indicating the track was stereo audio. switching to a 5.1 track and back to then 7.1 track fixes it. this is apparently a longstanding TvOS bug. switching around like that is not going to be family-friendly so i might just have to stop adding the 7.1 track to my handbrake encodes.

somehow though the appleTV+ app seems to properly output decodable atmos 7.1 audio consistently. but apple does seem to have a lot of bugs around audio as this thread attests to. i'm sure it's a hard problem with all the different TVs, soundbars and AVRs out there.

 

[priitv8]

AFAIK, Infuse can do its own decoding (e.g. codecs not supported by Apple like DTS or Dolby TrueHD, or can pass through compatible formats (mp3, aac, Dolby Digital), if set to "do not transcode"), so the number of variables is bigger than tvOS native decoding. Truth be told, I do not know, if Intune makes use of tvOS native media player at all, or decodes and renders all formats by itself.
tvOS natively decodes only lossy Dolby formats and sends them out from HDMI in already decoded PCM format.
So far I have not seen any problems with that. The only surprising thing I discovered when encoding with Handbrake was, that DD+ allows to encode to bitrates up to 1.5Mbps but tvOS will freak out, if the rate for DD+ exceeds 784kbps.