Does Atmos work if you "Airplay" your Macbook/Mac Pro to the Apple TV and play Atmos enabled video?

Discussion in 'Apple TV and Home Theater' started by Starfyre, Jun 6, 2018.

  1. Starfyre macrumors 68030

    Starfyre

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    #1
    As the topic states, I see that Apple TV is able to play Dolby Atmos with any content from iTunes directly off of the Apple TV. Question I have is, if I use Airplay on my Macbook or Mac Pro that has Atmos enabled content, or buy off of itunes... will the Atmos still play from the Apple TV? Or is it limited to "services" available on the Apple TV?
     
  2. kissfan macrumors regular

    kissfan

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    #2
    I don’t think Atmos is available until tvOS 12 in the fall.
     
  3. Starfyre thread starter macrumors 68030

    Starfyre

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    #3
    Sure, but I need to know now whether my hopes are misplaced in what having Atmos in Apple TV really means.
     
  4. priitv8 macrumors 68040

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    #4
    No, today it does discard the Atmos data so it plays back exactly like a DD+ track without Atmos.
     
  5. BODYBUILDERPAUL macrumors 65816

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    #5
    Out of interest, on the Apple TV 4K page, Apple are promoting a few Netflix shows as well as a few iTunes 4K films with Dolby Atmos.

    Starfyre, for iTunes film, Dolby Atmos is only on 4K film which can't be downloaded to your Mac.

    Instead of Airplaying content from your Mac, how about using the Computers App for Home Sharing maybe that might see the Atmos data???
     
  6. JeffPerrin macrumors 6502

    JeffPerrin

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    #6
    The problem with this is, last I checked, iTunes for Mac only provides the old format Dolby Digital 5.1 only. IF iTunes for desktop adds DD+, then you should be able to Airplay Atmos content to the Apple TV (when ATV supports Atmos).

    But I kind of have to think the movie studios will not be allowing downloading of premium format material like 4K or Atmos for some time...
     
  7. priitv8 macrumors 68040

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    #7
    But it is totally possible to download a testclip with DD+ sound (demo from dolby site) and add it to your local iTunes library.
    If it is the regular DD+ 7.1, then aTV plays it back nicely in PCM 7.1.
    If it contains also Atmos, the playback happens in PCM 5.1
    So iTunes in itself does not block or hinder DD+
    I don’t know where exactly does Atmos go missing in this chain.
     
  8. JeffPerrin macrumors 6502

    JeffPerrin

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    #8
    I was responding to the OP in regards to purchased iTunes content. Due to licensing restrictions, I doubt we'll see iTunes 4K (and also most likely Atmos) anywhere but on the Apple TV Movie store (streaming).

    In my previous (and extensive) multichannel testing, the only multichannel format I could get to reliably work via Airplay or local network were the officially supported variants for each ATV. So I wouldn't expect Atmos support of any kind before tvOS 12.
     
  9. priitv8 macrumors 68040

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    #9
    True. I am still hoping that local content will also preserve the Atmos compatibility. That implicitly means AirPlay or Home Sharing. Maybe I’m just naive.
    HDR10 is also fully supported in local library. Then again Dolby Vision is not. iTunes ingests it, but it does not play back in any way.
     
  10. loekf macrumors 6502a

    loekf

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    #10
    I don't have high hopes yet...

    Looking at the way Amazon handles Atmos in the FireTV cube, there are basically three ways Atmos could be implemented:

    1) The FireTV decodes Atmos and outputs 7.1 PCM over HDMI (= highest quality or best available quality it is called). Apple could do the same. For me, this is useless, but you get higher quality than Dolby Digital 5.1. Basically it's like TrueHD. Higher bitrate. Why is it useless, Atmos is all about more speakers, even upfiring speakers, to get more sound immersion in the vertical dimension.

    2) Same 1), but Apple strips the 5.1 "core" and outputs it via passthrough, so via HDMI

    3) Apple offers a higher quality option, but bitstreaming the original audio track (so all Atmos info, so speaker layouts like 7.2.1 (2 upfiring speakers) are usefull.

    My bests are on 1)....

    (unfortunately)

    Interesting enough the sounds options are already different tvOS 12.0 beta:

    http://www.avsforum.com/forum/39-ne...22-apple-tv-tvos-public-beta-releases-13.html

    but no signs of Atmos..
     
  11. vipergts2207 macrumors 68000

    vipergts2207

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    #11
    I don’t think #1 is true. This AVS thread has multiple comments saying no source devices decode Atmos content themselves.

    http://www.avsforum.com/forum/39-ne...e-tv-4k-support-dolby-atmos.html#post56292358
     
  12. mpainesyd macrumors 6502

    mpainesyd

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    #12
    Airplay on iTunes currently seems to be limited compared with iOS devices so don’t expect too much once Atmos is supported on ATV. However you should be able to use Homesharing to play media from your Mac using the ATV Computers app. That works for me for playing to a pair of Homepods (from ATV) but iTunes on the Mac does currently not play stereo to the paired Homepods.
     
  13. priitv8 macrumors 68040

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    #13
    Yep. PCM over however many channels won’t be called Dolby Atmos. The full stream and metadata need to reach the DA decoder. This is the single instance in the playback chain, that (has been made) aware of actual speaker layout, distances, sizes, crossover frequencies etc.
    So only bitstreaming will do.
    If Apple wants to inject system sounds, then it must re-encode internally. That is how current DD5.1 audio output setting works.
     
  14. z06gal macrumors 6502a

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    #14
    Why would Apple NOT just offer passthrough since so many AVR's support it? I can't fathom why they would want to decode but I confess I don't understand what is involved either way
     
  15. priitv8 macrumors 68040

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    #15
    What we know thus far is, that Apple needs to be able to let also Siri speak and system sounds be added.
    Lets wait and see what do they come up with in tvOS 12.
     
  16. cynics macrumors G4

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    #16
    This. An encoded audio stream can't be modified until its decoded.

    It doesn't stop at Siri and added system sounds though. Also volume normalization/sound check/whatever. But I would think most importantly would be AirPlay, there has to be some level of audio/video synchronization which typically requires a decoded audio stream.

    I also find it hard to believe that someone could find their receiver decoding better when the source is the ATV with its associated streaming services. Downmixing, not sure but I imagine the receiver would be better at it though. I think most people just dont like how the DOLBY logo isn't lit up on the receiver.
     
  17. priitv8 macrumors 68040

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    #17
    This again, is part of Dolby specification. Called Dynamic Range Control Profiles. This DR compression is handled by Dolby decoder. Probably is also inside current tvOS.
     
  18. benji888 macrumors 68000

    benji888

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    #18
    "

    "
    From Apple Support Document (published Sept. 17th): https://support.apple.com/en-us/HT204069
     
  19. Starfyre thread starter macrumors 68030

    Starfyre

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    #19
  20. priitv8 macrumors 68040

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    #20
    As I see it, it’s not an AirPlay problem (you can AirPlay from your iTunes library from Mac or iOS, Atmos is retained).
    I think the problem with AirPlaying from tvOS is that it does not pass the bitstream but rather decodes it.
    I don’t think AirPlay will carry multichannel PCM signal.

    But the answer to original question is YES.
     

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