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Q: 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

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Q: AppleTV 4 surround sound issue

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  • by Gino_Cerullo,

    Gino_Cerullo Gino_Cerullo Nov 11, 2015 10:42 AM in response to mechanic43
    Level 3 (567 points)
    Apple TV
    Nov 11, 2015 10:42 AM in response to mechanic43

    Regarding your issue re: AAC 2-ch Stereo vs AC3 5.1 Surround (Pass-thru), I have videos encoded the same way using Handbrake. Like you I have to make sure to switch which audio track is being used while playing the video. This is disappointing because the Apple TV 3 would automatically choose the better AC3 5.1 Surround when presented with both type of audio. I'm going to consider this a bug and submit it as such to Apple. Hopefully they will fix it and return the behaviour of previous Apple TVs.

     

    As for outputting the "Full Dynamic Range," I believe it is in fact doing that but there is a audible difference in the loudness when switching between the 2-ch stereo track and the surround track, the 2-ch track is played louder. There is only a slight difference when switching between "Reduce Loud Sounds" and "Full Dynamic Range" in both the 2-ch and surround settings but it is there in both.

  • by JMac12,

    JMac12 JMac12 Nov 11, 2015 10:50 AM in response to Gino_Cerullo
    Level 1 (0 points)
    Nov 11, 2015 10:50 AM in response to Gino_Cerullo

    Exact same issue!  This shouldn't even be a bug... hopefully Apple release update soon.

  • by mechanic43,

    mechanic43 mechanic43 Nov 11, 2015 4:55 PM in response to Jon Walker
    Level 1 (87 points)
    Nov 11, 2015 4:55 PM in response to Jon Walker

    No again reduce loud sounds is not on in the audio menu and under the info menu it is set to full dynamic range.  I have a ticket into apple on this issue they were able to duplicate it.  I am waiting for a reply from there engineering group and have a call back scheduled for tomorrow.

  • by mechanic43,

    mechanic43 mechanic43 Nov 11, 2015 4:59 PM in response to Gino_Cerullo
    Level 1 (87 points)
    Nov 11, 2015 4:59 PM in response to Gino_Cerullo

    The difference is when playing back AC3 5.1   tracks from the same movie and from the same sequence.  I can switch back to my ATV 3 and play back the same AC3 5.1 track at the same part and the difference is dramatic.  I have a ticket into apple which was escalated to there engineers, I am waiting for a call back scheduled for tomorrow.  The person I talked to said this definitely sounds like a bug and would probably have to be fixed in an update to tvOS.  He can duplicate it by the way.

  • by jvulto,

    jvulto jvulto Nov 16, 2015 12:12 AM in response to mechanic43
    Level 1 (4 points)
    Nov 16, 2015 12:12 AM in response to mechanic43

    Just finished some testing after emailing with programmer of 'Theater Test' application. Finally (after update) this app seems to work and proofing evidence of 8 channel playback via ATV 4. With both ATV4 and receiver set to 'auto' for decoding mode, the receiver receives a 7.1 LPCM stream NOT a DD stream. With that setup I am able to test ALL 8 channels of my surround system accordingly.

     

    Via some research I found that LPCM is sent by the ATV after decoding the stream. If ATV4 was able to pass-trough the DD+ signal it would show DD+ at my receiver. This IS the case when setting ATV audio to 'surround'. In that case however only DD 5.1 is sent to the receiver (shows in the display).

    This proofs that ATV4 for now is not supporting DD+ in pass through mode. I guess (hope) this is a software issue.

  • by Steve Lidie,

    Steve Lidie Steve Lidie Nov 17, 2015 6:22 AM in response to jvulto
    Level 1 (65 points)
    Nov 17, 2015 6:22 AM in response to jvulto

    Too bad I do not understand all the tech-speak in this thread, but this is the text of a report I sent to Apple:

     

    I have lots of Dolby Digital 5.1 surround movie content which has always played properly on previous versions of Apple TV 1, 2 and 3. By playing properly I mean that the A/V receiver shows 5 speakers active - center, left/right front, left/right rear and SW with LFE effects.  But with ATV 4 All I get are left/right front (and possibly center, I actually do not recall as I type this).

     

    The connections between ATV, the A/V receiver and the TV have not changed, and I can replicate the issue by simple swapping in and out an ATV 4 and an ATV 3: with ATV 3 all speakers “work” but with and ATV 4 in place I only get stereo (or as I mentioned, possible a center as well).

     

    The setup is simple and has been in place for years:

     

      . ATV connects to A/V receiver via HDMI

      . TV connects to A/V receiver via HDMI

     

    I see lots of comments on this issue.  If I switch to a non-ATV source DD 5.1 works fine, it’s only ATV 4 that appears broken.  I have gone into Setup and the only audio setting that seems relevant is to switch from Auto to Surround, but that does not appear to have an affect.

     

    And yes, all the 5.1 content has AAC and AC3 passthru, if I am speaking the jargon correctly.

  • by bodosom,

    bodosom bodosom Nov 17, 2015 9:00 AM in response to Steve Lidie
    Level 1 (28 points)
    iPhone
    Nov 17, 2015 9:00 AM in response to Steve Lidie

    Steve Lidie wrote:

     

    Too bad I do not understand all the tech-speak in this thread, but this is the text of a report I sent to Apple:

    This is a known difference.  It may be a bug or simply a poorly documented change.  tvOS 9 selects the first soundtrack.  iOS 8 on the ATV3 selects a 5.1 (AC-3) soundtrack if one is available (or is in the first n soundtracks).

     

    If Apple feels that consumer sourced video content should stereo (say from your iPhone) or that such content should be flagged the same way Apple does it then it's poorly documented.  If someone has a statement from Apple that the way the ATV3 works is the "right" way then it's a bug.  I'm guessing that the previous behavior is like using a private API.  When it stops working it's not a bug.

  • by Steve Lidie,

    Steve Lidie Steve Lidie Nov 17, 2015 9:27 AM in response to bodosom
    Level 1 (65 points)
    Nov 17, 2015 9:27 AM in response to bodosom

    OK, that I understand, thanks.  What I do not know how to do is ensure the 5.1 audio track is first .. does that mean, somehow, re-Handbrake every media item?

  • by bodosom,

    bodosom bodosom Nov 17, 2015 10:49 AM in response to Steve Lidie
    Level 1 (28 points)
    iPhone
    Nov 17, 2015 10:49 AM in response to Steve Lidie

    Steve Lidie wrote:

    What I do not know how to do is ensure the 5.1 audio track is first

    You could reconvert the original with Handbrake but I'm sure it would much faster to demultiplex the file and remultiplex the tracks in the desired order.  I've never done this but perhaps subler or ffmpeg can remux without (re-)transcoding.

  • by Gino_Cerullo,

    Gino_Cerullo Gino_Cerullo Nov 17, 2015 12:21 PM in response to bodosom
    Level 3 (567 points)
    Apple TV
    Nov 17, 2015 12:21 PM in response to bodosom

    bodosom, thanks for pointing us in the right direction. Subler will fix this issue by changing the default audio source in the video file and it does it without transcoding.

     

    First, for those who need it, Subler can be found here: https://bitbucket.org/galad87/subler/wiki/Home

     

    Once you've downloaded and installed the app launch it and make some changes to the preferences (see screen capture below.) I do this because I don't want to convert any of the audio.

     

    Screen Shot 2015-11-17 at 2.32.21 PM.png

     

    Next open a video file in Subler. You'll notice that the AAC 2-ch Stereo track is the default.

     

    Screen Shot 2015-11-17 at 2.54.52 PM.png

     

    Deselect the 2-ch and select the surround track of your choice. In my case I chose the only one available, the AC3, 6-ch, which is the 5.1 channel Dolby Digital surround track.

     

    Screen Shot 2015-11-17 at 2.55.09 PM.png

     

     

    Now save the video and test it on the Apple TV.

  • by Steve Lidie,

    Steve Lidie Steve Lidie Nov 17, 2015 3:23 PM in response to Gino_Cerullo
    Level 1 (65 points)
    Nov 17, 2015 3:23 PM in response to Gino_Cerullo

    SOB.  The Subler trick worked perfectly.  Many thanks.  I verified that you can simply have Subler Save the original in the iTunes Movies folder too, so it's (relatively) efficient to use this technique on all the media files.  Still a PITA, but at least ATV 4 is no longer relegated to the dungeon of shame and non-use.

  • by Steve Lidie,

    Steve Lidie Steve Lidie Nov 17, 2015 4:07 PM in response to Steve Lidie
    Level 1 (65 points)
    Nov 17, 2015 4:07 PM in response to Steve Lidie

    Of note, movies purchased via iTunes work just fine, this is what Subler shows:

     

    Screen Shot 2015-11-17 at 7.05.34 PM.png

  • by Mark Hodges,

    Mark Hodges Mark Hodges Nov 20, 2015 6:49 AM in response to pwnell
    Level 1 (15 points)
    Nov 20, 2015 6:49 AM in response to pwnell

    Here's my data points: ATV4 to TV via HDMI, TV to Onkyo 5.1 AVR via digital audio. Worked fine with ATV3. With ATV4's Surround Sound set to Auto or Dolby, 100% of what I play turns on the Dolby section of the AVR. This includes obvious stereo content such as iTunes music and older Hulu and Netflix content. Following a suggestion above, setting ATV4's Surround Sound to Stereo gives me correct two channel output. The wife asks the obvious question: how does she know what should be Dolby and what should be stereo? Yeah, good luck with that. Hoping for a fix from Uncle Tim. Wonder if it is worth calling Apple support?

     

     

    I also played with Surround Speaker Check, Dolby works as expected.

  • by bodosom,

    bodosom bodosom Nov 20, 2015 8:49 AM in response to Mark Hodges
    Level 1 (28 points)
    iPhone
    Nov 20, 2015 8:49 AM in response to Mark Hodges

    Mark Hodges wrote:

     

    Here's my data points: ATV4 to TV via HDMI, TV to Onkyo 5.1 AVR via digital audio. Worked fine with ATV3. With ATV4's Surround Sound set to Auto or Dolby, 100% of what I play turns on the Dolby section of the AVR. ... Wonder if it is worth calling Apple support?

     

    If it's exactly as you report either your ATV defective or AVR is reporting the wrong status.

     

    Using content from the Music app or the Computer (iTunes) app (although they are just examples) that is correctly encoded:

    • Given Surround:AUTO, 7.1, 5.1 and 2.0 input produce 7.1 PCM with the correct number and placement of channels
    • Given Surround:DOLBY, 7.1, 5.1 and 2.0 input produce transcoded 5.1 with correct channels.

     

    It's been suggested that ATV4gen decodes bitstreams to do volume/loudness/dynamic range compression (so called midnight mode) on the resultant PCM streams.

  • by W.R.R. Farid,

    W.R.R. Farid W.R.R. Farid Nov 25, 2015 2:53 AM in response to pwnell
    Level 1 (0 points)
    Nov 25, 2015 2:53 AM in response to pwnell

    So this is getting so confusing for me now. Somehow Apple always makes things so confusing for people who just want things to work how they are supposed to.

     

    I am thinking about buying the new ATV4. I have a receiver and all I want is that when I play movies (through Plex or some other software) that the ATV just passes my bitstream sound through to my AV receiver without modifying it (ATV will be connected to the AVR which is then connected to my TV). So I just want the ATV not to do anything at all with the sound. If it is DD, DTS, stereo or whatever. I just want the ATV to just pass it through to my receiver and let the receiver do the work.

     

    Is this possible? Seems to me after reading the whole topic that it is not.

     

    I really like the new ATV and the interface with the remote. But if it's not going to do what I want than it's useless. After all Apple should realise I didn't buy my expensive AVR and speakers and had it set up so Apple can play their simulated tracks over it.

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