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AppleTV 4 surround sound issue

i just acquired an AppleTV 4 to replace my AppleTV 3. Since I used to connect the optical audio out to my Yamaha surround sound receiver, I am forced to use only hdmi. That would not be a problem for two reasons:


1. All AppleTV content plays with the receiver showing PCM and not DTS or some other form of surround sound.

2. All my movies i encoded are strictly playing in stereo only. The DTS stream is seemingly not being passed through hdmi.


Routing hdmi to tv then optical from tv to receiver does not change anything.


How can I fix this? Surely I should be getting DTS with a Yamaha rx- v1900 receiver?

Posted on Nov 1, 2015 1:32 AM

Reply
321 replies

Nov 9, 2015 9:45 AM in response to bodosom

Just finished some additional testing.

With ATV set to sound mode: "auto", and Receiver set to "auto" upon playing dolby 5.1 content:


- Receiver detects PCM 3/4/.1 but only L & R surround speakers (lef & right to listening positions) produce sound. The BACK surround speakers remain silent. Which could be as expected since only 5.1 channels are being sent. However I would expect the BACK surround speakers to produce sound and the surround speakers (left & right to listening positions) to remain silent. Someone agree with this?


- Same story upon listening to Netflix. I do not know however if Netflix streaming via ATV is done in DD+ or DD.


See below a screenshot of Amplifier menu (Marantz SR6006) set to auto while sending Mad Max Fury Road movie in 5.1 via ATV with surround in 'auto' mode.

Back surround Left and Back surround Right silene. Left surround and Right surround providing 5.1 surround sound.


User uploaded fileUser uploaded file

Nov 9, 2015 10:09 AM in response to jvulto

jvulto wrote:

With ATV set to sound mode: "auto", and Receiver set to "auto" upon playing dolby 5.1 content:


- Receiver detects PCM 3/4/.1 but only L & R surround speakers (lef & right to listening positions) produce sound. The BACK surround speakers remain silent. Which could be as expected since only 5.1 channels are being sent. However I would expect the BACK surround speakers to produce sound and the surround speakers (left & right to listening positions) to remain silent. Someone agree with this?


No. AC-3 (3/2/.1) has no rear data (which back in the day was mono) so it would be a error to send the surround data to the rear channels. That would be 3/4/.1 with no data in the surround channels.

Nov 9, 2015 11:37 AM in response to bodosom

I think what jvulto is running into is that for many 7.1 receivers, when 5.1 content is sent as a 5.1 stream to the receiver, the data in the SL and SR are "matrixed" to create SBL and SBR, or 7.1, content from that 5.1 source.


But when a source (Apple TV, PS3 used to do this for a while) provides 5.1 content in a 7.1 channel PCM stream, since the SBL and SBR are silent, the receiver doesn't try and matrix anything, because it assumes that the SBL and SBR channels are being provided. So you only get 5.1.


My bigger problem is the fact that the Apple TV has seemingly changed the way it handles 5.1 audio, especially on BD Rips and non-Apple files. Used to be track 1 was stereo AAC and track 2 was 5.1, and the Apple TV would default to the 5.1 Now it defaults to stereo, which is problematic for me. Hopefully there's an easy fix either in iTunes or in the TVos, otherwise, reencoding and/or explaining to my wife how to manually choose 5.1 each time she starts a film isn't going to be a good look.

Nov 9, 2015 1:20 PM in response to bodosom

User uploaded file

@bodosom

When setting ATV to audio mode "surround" upon playing the same 5.1 content Mad Max Fury Road:

- the receiver shows Dolby Digital 3/2/.1

- The Surround L&R are silent

- The BACK surround speakers produce the 5.1 surround

So this is the opposite of what is happening in ATV audio mode "auto".


I have not tried 'real' 7.1 content since for that I would have to buy Terminator Genesis. Tempting...

As it seems to me now is that when I want 5.1 to be correctly played I am obliged to set ATV sound setting to "surround".

When I want 7.1 I am obliged to set ATV sound setting to "auto".

Nov 9, 2015 1:39 PM in response to jvulto

When setting ATV to audio mode "surround" upon playing the same 5.1 content Mad Max Fury Road:

- the receiver shows Dolby Digital 3/2/.1

- The Surround L&R are silent

- The BACK surround speakers produce the 5.1 surround

So this is the opposite of what is happening in ATV audio mode "auto".

What is your system's programmed "fallback" for DD5.1 playback to 8 speakers? I programmed my system to do this during the initial set-up years ago. As to the "Auto" mode not doing this, remember that it doesn't seem to differentiate between active and empty channels and so applies default 8-channel output to speakers.

User uploaded file

Nov 10, 2015 5:41 AM in response to pwnell

I am having pretty much the same problem as everyone, but I can add another odd wrinkle. In Auto ATV4 plays only PCM, either 2-channel for music and some TV shows or movies (which is normal) or 7.1 for movies and TV shows that are in surround. When I set the unit to Dolby Surround, however, I get the following strange results:


Surround movies and TV shows display as Dolby Digital 5.1, and I am getting sound from 5.1 speakers. This applies on both Netflix and content streamed from iTunes on my PC.


Music streamed from iTunes on my PC and the movies and TV shows that were playing in 2-channel PCM in Auto mode also display as Dolby Digital 5.1, but sound comes only from the two front speakers.


Apple Music content plays in two channels and displays as PCM.


Finally, no matter how I set the surround sound in ATV4, all content from TV network apps (NBC, ABC, PBS, etc.) delivers only 2-channel sound. This does not seem right, since the same shows, like Heroes Reborn, play and display Dolby Digital 5.1 from my Dish Network box. If it were only one app, I would blame the app, but under the circumstances, I suspect an ATV4 issue.


Sure hope Apple comes out with a fix for this soon.

Nov 10, 2015 5:59 AM in response to pwnell

I also discovered that (currently) the way to obtain 5.1 channels from Apple TV 4 is to go to Settings>Audio and Video>Surround Sound and change the default from Auto to Dolby Surround. The point is that the Auto setting should be sufficient to acquire 5.1 channels when that is what is "supplied" by the program. This will probably be fixed in a later patch.

Nov 10, 2015 6:17 AM in response to pwnell

I am so confused by all of this. I want my receiver to do the decoding, not Apple TV. If I set to auto and I play a music file from my iTunes library it comes out of left and center channel instead of left and right. Always says PCM and all seven speakers are active even though no sound coming from them. If I play same song from iTunes on my roku with receiver set to auto surround it comes out as stereo as it should So I don't think the file is bad.

I was really hoping that this would be my one box solution and I could get rid of ruku and the htpc that is in my system. The few movies I have in Dolby atoms I can live with out if I can get 5.1 and stereo to change automaticall like it should. Also think receiver should recognize Dolby digital encoded movies and switch to that on auto instead of just saying pcm.

I Know on my Blu ray player I had to change a setting somewhere to get it to do it.

Nov 10, 2015 6:39 AM in response to RufusJazzDog

RufusJazzDog wrote:

Finally, no matter how I set the surround sound in ATV4, all content from TV network apps (NBC, ABC, PBS, etc.) delivers only 2-channel sound. This does not seem right

And yet it probably is. Those apps are probably using the same files as the web versions. You're lucky they're not mono.

I'm not completely sure but I think HBO GO is providing surround content.

Nov 10, 2015 6:45 AM in response to csmonroe

csmonroe wrote:


I also discovered that (currently) the way to obtain 5.1 channels from Apple TV 4 is to go to Settings>Audio and Video>Surround Sound and change the default from Auto to Dolby Surround. The point is that the Auto setting should be sufficient to acquire 5.1 channels when that is what is "supplied" by the program.

There have been multiple postings in multiple threads on multiple forums that verify that 5.1 content is correctly handled with Surround set to DOLBY or AUTO. In the former case I suspect theres a decode/encode cycle which is why the dialnorm data is deleted from the bitstream. In the latter it's LPCM output with correct channel assignment.

Nov 10, 2015 6:49 AM in response to mikealvey

mikealvey wrote:


I am so confused by all of this. I want my receiver to do the decoding, not Apple TV.


I don't expect that to happen on the AppleTV5,3. The next version could do things completely differently (and add UHD).

They could do a software update but I suspect the target market is household that have their over-the-top box plugged into a television not an AVR.

Nov 10, 2015 7:36 AM in response to bodosom

OK, so when I play a Dolby Digital 5.1 movie on ATV3, my Yamaha receiver displays Dolby Digital 5.1. When I set ATV4 surround sound to Auto and play that same movie, my Yamaha receiver displays PCM 7.1. Are you saying that I am actually getting the same sound in both cases, despite the different displays on my receiver? I am certainly getting sound from at least 5.1 speakers in ATV4 Auto. I have not done a careful listening test to compare.

AppleTV 4 surround sound issue

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