Q: AppleTV 4 surround sound issue

Hey All,

We noticed that there's a bit of confusion with the Dolby Surround settings, hopefully this will clarify some of your questions

http://developer.dolby.com/News/Dolby_Audio_Support_on_Apple_TV.aspx

- Dolby Developer Support -

SO a $150 ATV has a better Dolby processor then my $2000 receiver. I don't think so !!!!! And what changes did Apple do to there ATV from there initial released software to what is out now ??

Has anything changed recently ?  Bug fixes pushed?

I will confirm that I can now send PCM audio when set to "auto". I could not a few weeks ago. Previously auto would onply send stereo, not matter what I did to settings on my receiver.

AFter reading ding this post, I met into the ATV, chamged for DD to auto, and it now works.

Thanks and most of us are aware of that. The issue is that the Receiver can no longer apply it's own processing to fully use a 7.1 system. You are left with no sound for the rear two speakers. ATV 3 at least allowed the receiver to use PLX II or DTS  to fully utilized all 7 speakers.

We noticed that there's a bit of confusion with the Dolby Surround settings, hopefully this will clarify some of your questions

There is no confusion regarding either how the Surround Sound settings worked before or how they work after the release of the tvOS 9.1 update. The only question is why Apple developers decide to first create and then leave a gaping hole in Dolby audio support on the TV4. By electing to decode "non-multichannel" Dolby audio within the TV4 device and pass it to downstream devices as PCM, Apple has, in effect, chosen to terminate direct, automatic "full" support of Dolby center channel mono, 3-channel Front, and active Dolby ProLogic II encoded audio content. When passed through to the AVR, such content was previously decoded and processed both automatically and correctly by AVR Dolby processing circuitry without further action on my part. However, following the tvOS v9.1 update, I must now manually ensure additional passive processor options are engaged to restore center channel (mono or 3-channel Front) and/or recover DDPLII surround channel audio for speaker output. Unfortunately, the application of these passive settings are themselves tied to "effect" options which now must also be selected and which further "colorize" and modify audio playback... And do you even want to go into the Dolby to PCM normalization and automatic loudness control issues experienced by some users when the Dolby encoding are decoded by the TV4 for PCM output?

The obvious remedy (or at least what seems obvious to many users) would be to add a fourth Surround Sound user option (Dolby Passthrough) to the current Auto, Dolby Surround, and Stereo TV4 option settings. This option would pass Dolby audio content (either AC-3 or E-AC-3) directly to the AVR for automatic decoding, post processing, normalization, and/or ALC handling as might be required. This is not anything new since AC-3 audio was "fully" supported in this manner prior to the release of tvOS v9.1 and the Infuse Pro app currently supports HDMI DTS passthrough on the TV4 at this time. In short, I don't know (or really care) why Apple developers insist on having a "Dolby Surround" mode option that cannot handle Dolby audio content not encoded with an LFE channel, but I am anxious for them to restore a "passthrough" option that does "fully" support Dolby audio as Dolby audio content.

No confusion here, simply put, it is a mess in its current state.

Tested with Infuse Pro with DD and DTS passthrough enabled and having the ATV set to audio-mode 'auto'.

- DD 5.1 and 7.1 both get received unencoded by my receiver and get decoded accordingly.

- DTS 5.1 and 7.1 both get received unencoded by my receiver and get decoded accordingly.

Streaming Dolby ATMOS through my ATV has not been a success so far. This could well be caused by the data I am streaming. It is supposed to enclose ATMOS data but signal is received by my receiver as PCM stereo only. I tested this with Minions and Sicario material with mentioned ATMOS streams included...

Thank you for the input on this frustrating topic DD.  I have a followup question.  Regarding "Decoding the audio inside of the Apple TV enables Apple to support several features such as mixing of other sounds from the system, Siri^® voice input, and so on."   Is this why Apple will not include an option to just send the bitstream and allow the AVR to do it's job decoding?  ATV3 did not have siri integration, so that explains that.   Do you think there is a way the two could live togather:  be able to send a bitstream for the AVR (or soundbar or TV) to decode and also somehow have system sounds/siri audible?

Personally, I would still want the option even if I lose siri/system sounds.  I would use it for movie-time.

Infuse users - when you pass-through the bitstream (DD/DTS) do you still get siri/system sounds?

Thanks, yes I have Infuse Pro, but in it's current state, it is unable to fetch the metadata for my excessively large iTunes library. Therefore, at this time, renaming  my files to make Infuse work properly is not an option. Until we all find out, from Apple, that they are not going to support the bitstream passthrough option, many of us would like, I will be using my atv3's.

Until then, everybody that would like passthrough, hammer them with feedback, as a problem.

Thanks

One other point DD,

I think for many folks the ATV4 works as explained on the DD page you linked.  It does for me however I know some folks have issues.  My problem, and I think the problem for many is:

We want to watch movies in their best native sound format (regardless of where that movie is sourced) and not have the streaming device force of to one or two options (one of which there is very limited content for).  This includes:

DTS

DTS Master Audio

Dolby True HD

...or any special mix that receivers will do to the native format

along with the ATV "supported"  DD (AC-3), DD+ (E-AC3), and stereo.

So, considering you are a Dolby person, what would it take for the ATV to also somehow allow the users to hear a Dolby True HD movie in actual True HD sound on their 5.1/7.1 system?

Thanks again for your input here.

DOn't forget Aboutaleb Dolby Atmos and DTS:X

moochman wrote:

 

SO a $150 ATV has a better Dolby processor then my $2000 receiver. I don't think so !!!!! And what changes did Apple do to there ATV from there initial released software to what is out now ??

Unless broken all certified decoders are the same.  So yes the one in the ATV4gen is just as good as the one in your AVR.  Now some AVRs are limited in what processing they will do to a multi-channel PCM input* compared to a bitstream and that's not under Apple's control.

The problem isn't the decoder.  It's the ATV4gen encoder options or the lack of pass-through (which I believe has never happened on 4gen).  This may all be fixed in 9.2 or not.  Fixed in 9.3 or not.  The more people that file sensible feedback the more likely Apple will respond sooner rather than later.

*presumably as cost savings or just laziness since, just like Apple, they have to decode the stream to post-process

bodosom wrote:

 

 

*presumably as cost savings or just laziness since, just like Apple, they have to decode the stream to post-process

bodosom what do you think about this as a reason:  "Decoding the audio inside of the Apple TV enables Apple to support several features such as mixing of other sounds from the system, Siri^® voice input, and so on."

meegwell wrote:

 

bodosom wrote:

 

 

*presumably as cost savings or just laziness since, just like Apple, they have to decode the stream to post-process

 

bodosom what do you think about this as a reason:  "Decoding the audio inside of the Apple TV enables Apple to support several features such as mixing of other sounds from the system, Siri^® voice input, and so on."

My comment was about AVR companies being unimaginative, cheap, lazy or careless not Apple*.  The rationale for decoding in the ATV has been discussed at length.  I don't understand what Siri has to do with it (and system sounds work in the ATV3) but if you turn off compression and disable system sounds then there's no reason not to do pass-through.  Or you can take the TiVo approach and document the fact that system sounds are disabled when AC-3 is active.

*This has been mishandled by Apple but to some extent because they failed to clearly describe what was going on.  When you remove the S/PDIF port everyone knows that means no more optical.  Saying we're adding audio-compression doesn't necessarily mean bit-streaming will be broken.

I Just found this thread after watching an iTunes movie (Bridge of Spies) streamed via my ATV4. My AVR was displaying PCM while it was playing. First, I am no techie when it comes to audio visual tech. i have read the article that is linked above. i have a 5.0 setup (no sub connected). The movie sounded pretty good with all 5 channels playing properly. Effects sounded pretty good In fronts and rears.

So what is the disadvantage, if any, of having the AVR show PCM instead of Dolby Digital? Any explanation would be appreciated in simple terms. Thanks!!