pwnell

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

Close

Q: AppleTV 4 surround sound issue

  • All replies
  • Helpful answers

Page 1 of 22 last Next
  • by Rob2160,

    Rob2160 Rob2160 Nov 1, 2015 1:44 AM in response to pwnell
    Level 1 (1 points)
    Nov 1, 2015 1:44 AM in response to pwnell

    Yes same problem exactly with mine.  I tried it using HDMI to TV then optical from TV to Surround system.  I could get sound but as you say, only in Stereo, and was unable to get DTS in any way.

     

    I returned mine and won't buy another until they restore the optical out.

  • by Steve Neal,Helpful

    Steve Neal Steve Neal Nov 1, 2015 9:09 AM in response to pwnell
    Level 1 (35 points)
    Nov 1, 2015 9:09 AM in response to pwnell

    1. Are you feeding HDMI to your TV and then taking optical from your TV to your amp? If so then some TVs don't support DD and/or DTS passthrough from HDMI to optical, and others require that you enable it in a configuration menu.

     

    2. You may need to alter the audio output settings in Apple TV 4.  I think they are not helpfully labelled.  My Apple TV 4 was playing Netflix content in PCM multichannel (i.e. decoding the Dolby Digital audio to multichannel PCM) by default, and only when I changed the audio setting did I get a Dolby Digital bitstream to my Amp over HDMI instead.  It may be your Apple TV is defaulting to PCM 2.0 output rather than bitstreaming because it doesn't think your TV can handle multichannel PCM (or Dolby?)

     

    Just a couple of thoughts.

  • by Rob2160,

    Rob2160 Rob2160 Nov 1, 2015 4:07 AM in response to Steve Neal
    Level 1 (1 points)
    Nov 1, 2015 4:07 AM in response to Steve Neal

    Hi Steve,

     

    What setting did you change in the Apple TV to get Dolby Digital?

     

    I tried all of the options on mine and could get sound but it was always PCM out of the TV. 

     

    Tried the options within the TV itself and still no joy.

  • by Roger Wilmut1,

    Roger Wilmut1 Roger Wilmut1 Nov 1, 2015 4:17 AM in response to Rob2160
    Level 9 (77,920 points)
    iTunes
    Nov 1, 2015 4:17 AM in response to Rob2160

    I've not had the chance to investigate this (mine hasn't arrive yet) but it's been reported that while setting the Surround sound option to 'Auto' produces a PCM output, setting it to 'Dolby Surround' produces Dolby Digital when the source material provides it.

  • by Steve Neal,

    Steve Neal Steve Neal Nov 1, 2015 4:28 AM in response to Rob2160
    Level 1 (35 points)
    Nov 1, 2015 4:28 AM in response to Rob2160

    Settings->Audio and Video->Surround Sound->Dolby Surround (sic)

     

    My receiver indicates it is being fed 7.1 PCM when in Auto mode and playing Daredevil in Netflix - and the rear speakers in my 5.0 set-up are definitely getting surround content.

     

    My receiver indicates it is being fed 5.1 Dolby Digital when in Dolby Surround mode and playing the same content in Netflix, and again I'm getting rear surround content.

  • by Rob2160,

    Rob2160 Rob2160 Nov 1, 2015 4:37 AM in response to Steve Neal
    Level 1 (1 points)
    Nov 1, 2015 4:37 AM in response to Steve Neal

    Thanks Roger and Steve,

     

    I did try setting it to Dolby Surround in the ATV4 but then there was no sound at all via Optical Cable from TV to the Audio receiver.   When I set auto I got PCM to receiver.

  • by Winston Churchill,

    Winston Churchill Winston Churchill Nov 1, 2015 4:44 AM in response to pwnell
    Level 10 (103,375 points)
    Apple TV
    Nov 1, 2015 4:44 AM in response to pwnell

    It may just be that you are mixing up your nomenclature, but Dolby Digital and DTS are different things.

  • by Steve Neal,

    Steve Neal Steve Neal Nov 1, 2015 4:46 AM in response to Rob2160
    Level 1 (35 points)
    Nov 1, 2015 4:46 AM in response to Rob2160

    Have you checked for any audio passthrough settings in your TV?

     

    HDMI audio passthrough to Toslink is a hit-and-miss affair with TVs.  Some TVs will only accept PCM 2.0 audio over HDMI, and only output Dolby Digital audio when it is received on broadcast received by their internal tuners.

     

    Some will accept DD and PCM 2.0 via HDMI and output this via Toslink.  (Some may even accept DTS)

     

    If your TV doesn't offer a solution then you could investigate something like this : http://www.amazon.co.uk/ZILONG-Extractor-Converter-TosLink-Version/dp/B010LRHNTW /ref=sr_1_1?ie=UTF8&qid=1446381753&sr=8-… 

     

    Some HDMI Audio extractors only extract PCM 2.0 - others will modify EDID to indicate Dolby Digital support to sources  and allow for DD audio to be extracted to Toslink.

  • by Jon Walker,

    Jon Walker Jon Walker Nov 1, 2015 5:07 AM in response to Steve Neal
    Level 6 (18,603 points)
    Nov 1, 2015 5:07 AM in response to Steve Neal

    You may need to alter the audio output settings in Apple TV 4.  I think they are not helpfully labelled.  My Apple TV 4 was playing Netflix content in PCM multichannel (i.e. decoding the Dolby Digital audio to multichannel PCM) by default, and only when I changed the audio setting did I get a Dolby Digital bitstream to my Amp over HDMI instead.  It may be your Apple TV is defaulting to PCM 2.0 output rather than bitstreaming because it doesn't think your TV can handle multichannel PCM (or Dolby?)

    On my system, the global "Surround Sound" setting determines the audio format output by the unit irregardless of the audio format encoded in the source file. In the "Auto" mode, the TV4 outputs audio in PCM with the source track mapped to 7.1 channelization—i.e., my enabled DD ProLogic 2 AAC stereo track is output as PCM stereo mapped to 7.1 stereo channelization and my secondary disabled DD5.1 AC3 surround audio track is output as PCM surround audio mapped to 6 of the 7.1 channels as programmed. On the other hand, if the global "Surround Sound" switch is set to "Dolby Surround," then my primary AAC audio track is output as stereo AC3 mapped to DD5.1 channelization and my secondary DD5.1 track is mapped to all 6 channels. Lastly, the global "Surround Sound > Stereo" setting outputs both my stereo AAC and AC3 DD5.1 audio tracks as Stereo PCM. In all cases, applicable receiver "Effects" settings worked normally. As a final test, I sourced some HiRes (24-bit 192.0 KHz) WAV stereo PCM audio files through the same TV4 global "Surround Sound" settings with the same results—i.e., the global setting determining the output compression format and source channelization determined the maximum possible number of channels mapped to the surround output format. However, it is still unclear if source PCM and AC3 source content is "passed through" natively or if all audio is "converted on the fly" by the TV4 to the user's targeted global "Surround Sound" setting and if so, what sampling settings are used.

    SJAUG.png

  • by Rob2160,

    Rob2160 Rob2160 Nov 1, 2015 5:20 AM in response to Winston Churchill
    Level 1 (1 points)
    Nov 1, 2015 5:20 AM in response to Winston Churchill

    These pictures might help.

     

    With Optical Cable from ATV3 to Sherwood receiver I get Dolby Digital with most movies - surround sound is perfect.

     

    With ATV4 and using Optical Cable from TV to receiver, I only get 'DSP"  The sound is clearly softer / flatter and very little surround.

     

    If I set Dolby Digital to ON with the ATV 4, no sound comes out of the TV's optical output.

     

    If I set it to Auto or Off I get the "DSP" from the TV optical output. p1.png

    p2.png

  • by Steve Neal,

    Steve Neal Steve Neal Nov 1, 2015 5:28 AM in response to Rob2160
    Level 1 (35 points)
    Nov 1, 2015 5:28 AM in response to Rob2160

    DSP suggests, I suspect, that your ATV4->TV->Sherwood route is enforcing PCM 2.0 only audio, so the DSP processing is there to create a surround sound signal from a stereo source.

  • by Steve Neal,

    Steve Neal Steve Neal Nov 1, 2015 5:32 AM in response to Jon Walker
    Level 1 (35 points)
    Nov 1, 2015 5:32 AM in response to Jon Walker

    Jon Walker - yes - I agree.  With Dolby Surround (sic) set as the output format I get 5.1 Dolby Digital output whenever playing back content - whether it is 2.0 or 5.1 content, and irrespective of the source codec.

     

    When watching content in the Swedish SVT Play app (which is I think H264 720/25p video + stereo AAC audio) I get a 5.1 Dolby Digital stream sent to my amp wth silence in the surround channels

  • by Steve Neal,

    Steve Neal Steve Neal Nov 1, 2015 7:18 AM in response to Jon Walker
    Level 1 (35 points)
    Nov 1, 2015 7:18 AM in response to Jon Walker

    Jon Walker - I see slightly different functionality when replaying my own content. I've just created a 1080/24p H264 video file with AAC 2.0 and AC3 5.1 audio tracks.

     

    With HDMI Audio output set to Auto (i.e. PCM with no limitation to stereo) :

     

    The AAC 2.0 track is output to my receiver as PCM 2.0

    The AC3 5.1 track is output my receiver as PCM 7.1

     

    (In other words the PCM format output by the Apple TV is changing dynamically based on content - and isn't fixed at a 7.1 output all the time. This means that receiver decoding of older Dolby Stereo surround content which is recorded 2.0 but decoded using ProLogic or similar can be used, which is not always the case if you are outputting 7.1 or 5.1 with silence in the non-stereo channels)

     

    There is an audible click in (not on the audio from) my Onkyo AVR as it switches from running in 2.0 to 7.1 - I'm guessing there are relays involved in 2.0 to 7.1 switching (as I had my amp configured for 2.0 content to be output to just the front left and right speakers, rather than being upmixed to 5.1 or 7.1)

  • by Jon Walker,

    Jon Walker Jon Walker Nov 1, 2015 7:59 AM in response to Steve Neal
    Level 6 (18,603 points)
    Nov 1, 2015 7:59 AM in response to Steve Neal

    There is an audible click in (not on the audio from) my Onkyo AVR as it switches from running in 2.0 to 7.1 - I'm guessing there are relays involved in 2.0 to 7.1 switching (as I had my amp configured for 2.0 content to be output to just the front left and right speakers, rather than being upmixed to 5.1 or 7.1)

    Suspect it is a difference in our receivers. Your Onkyo is probably newer and/or "smarter" than my older Pioneer AVR. If I first reset my receiver to "Auto Surround," then it does switch over to "Pure Direct PCM 7.1" or "Stereo PCM" depending on the audio track selected for the particular file on the TV4. However, once it switches to 7.1 PCM, my receiver stays in this mode even if I change my audio track selection or switch to a different video file (which then defaults back to my stereo track). Basically, I suspect your AVR either rechecks channelization each time it detects "new" activity while mine may not auto-detect channelization changes when checking for a mode change. Same thing happens when set to "Dolby Surround" on the TV4 even though the same receiver connected to the older TV3 via the same HDMI connector used to correctly switch between stereo and surround Dolby content automatically. Not sure what's causing the "sticking" in conjunction with the new device. Have a feeling that system differences are going to make full analysis somewhat difficult here. Could get very confusing.

    SJAUG.png

Page 1 of 22 last Next