Apple Tv4 dolby surround is broken

My ATV3 plays perfect dolby digital 5.1 audio from House of Cards and the House MD box-set which i bought off iTunes. I hook up the new ATV4 and it does not send a dolby signal to my amp when playing back the same content. Instead it chooses to decode the dolby signal into multiple parts and send it to my amp in PCM multi-channel format with a low dynamic range. It does Not sound very good. Had i known this before purchasing i wouldn't have picked it up. This is unacceptable and i am stumped as to why Apple would change such a significant feature on this device which is supposed to 'revolutionize' tv.


I mean why is it so hard to get something right? Apple had a reputation for making things 'just work', but lately i'm not sure anymore. The ATV3 was a perfectly good product with superb audio quality, so why mess with something that worked well for consumers? I really hope this can be fixed through a firmware/software update soon.

Apple TV

Posted on Dec 14, 2015 10:23 AM

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16 replies

Dec 14, 2015 12:22 PM in response to guygadvoir

Welcome to the Apple Community.


Have you tried adjusting the “Audio Mode" and the “Surround Sound" settings in settings > audio and video? It may be worth trying several combinations of these settings, although typically it is the “Surround Sound" setting that causes most problems for users.


I get stereo PCM from stereo, multichannel PCM from auto and DD from surround sound for iTunes movies


If you are using a sound system/receiver, make sure that you have correctly mapped the input port on your sound system to the output, if you are unsure about how to do this, refer to the manual that came with your sound system.

Dec 14, 2015 1:10 PM in response to guygadvoir

My ATV3 plays perfect dolby digital 5.1 audio from House of Cards and the House MD box-set which i bought off iTunes. I hook up the new ATV4 and it does not send a dolby signal to my amp when playing back the same content. Instead it chooses to decode the dolby signal into multiple parts and send it to my amp in PCM multi-channel format with a low dynamic range. It does Not sound very good. Had i known this before purchasing i wouldn't have picked it up. This is unacceptable and i am stumped as to why Apple would change such a significant feature on this device which is supposed to 'revolutionize' tv.


I mean why is it so hard to get something right? Apple had a reputation for making things 'just work', but lately i'm not sure anymore. The ATV3 was a perfectly good product with superb audio quality, so why mess with something that worked well for consumers? I really hope this can be fixed through a firmware/software update soon.

Join the club! Most of us feel the same way—assuming Apple would keep the original AAC to "Stereo" PCM strategy, pass through DD5.1 bitstreams as before, and add the ability to pass through higher capacity DD+7.1 bitstreams for the AVR to decode and process. Unfortunately, it may appear that Apple has a longer range view and may be trying to devise a uniform 1.0 to 7.1 strategy to handle additional WAV, AIFF, and/or AAC non-DD/DD+ multichannel possibilities.


Currently only the "Dolby Surround" Surround mode appears to pass DD5.1 content directly to the AVR. Even then there is still debate as to whether or not the "meta" DialNorm setting is being lost in some, most, or all cases. (Previously the "Auto" Surround mode appeared to lose both the LFE channel and the DialNorm value, as well as, change "active" Dolby Digital ProLogic II Matrix encodes to 2.0 "Stereo" PCM data streams requiring "passive" DD PLII matrix decoding.) As a result, many users have indicated loss in percussive "impact," audio "clipping" in the main audio channels, and/or a degrading of channel separation for "matrix" post-processing. In addition, different apps may play the same content differently—which may also affect playback quality and make it more difficult to determine the actual source of some issues. I personally don't know what to say since about 80% of my 10,000 file library no longer plays my AC3 tracks "correctly" on the TV4 as I originally encoded them but I'm not suffering the poor quality in playback that some are reporting. In fact, my video playback is an improvement over the TV3 and not affected by the other problem... thus far.

User uploaded file

Dec 15, 2015 3:01 AM in response to Winston Churchill

Thank you.


Yes, I've tried all the different combinations, which unfortunately have given me the same result. I just see 'Multichannel' on the AVR when forcing surround sound from the ATV4, which indicates the signal has been processed before reaching the receiver.


Thing is, I know my AVR is setup correctly because whenever I take the HDMI cable from the ATV4 and plug it into the ATV3 it works fine and I get full-bodied DD.


Another annoying factor is that when you lookup content in the iTunes store through the ATV4 it does not indicate whether the movie or episode you are about to buy is encoded in Dolby, it just shows HD, CC, and the synopsis. Hopefully this change is just another glitch, and not something permanent, as I would think twice about spending money to buy HD content which does not come with surround sound.


To the main point, I would like to see a return to where the audio channel is passed-through to my AVR, where it has all the necessary tools to cleanly decode and present pristine audio. If Apple decided to change this architecture for whatever reason/strategy and now decodes audio mid-stream, then a heads-up would be welcome so that some of us audiophiles who value this sort of thing can make an informed decision and choose not to buy an ATV4.

Dec 15, 2015 5:08 AM in response to Jon Walker

Thank you Jon.


I can appreciate the need to have changes in strategy from time to time, and have a long range view, but if you aim to improve on something why do it at the expense of breaking something that works as it should? To me, it looks like the focus was getting the ATV into the app ecosystem, and someone dropped the ball on one the fundamentals, which is good quality audio.


Anything is possible through software, so why not add an option in ATV4 settings for no-frills pass-though so things will work just like the previous generations of devices? Surely they must know there are millions of customers with AVR home theatre systems that would be first in line to upgrade to the new ATV? Imho Steve Jobs could force things on consumers successfully because he obviously and meticulously thought things through. Nowadays, that probably happens less...


You're right about different apps playing content differently. Have you tried using Infuse Pro? It does appear to play AC3 and DTS content quite well.

Dec 15, 2015 9:07 AM in response to guygadvoir

guygadvoir wrote:


This is unacceptable and i am stumped as to why Apple would change such a significant feature on this device which is supposed to 'revolutionize' tv.

I don't think I'm having dynamic range problems but I am having trouble with gain matching the ATV4gen because 2.0 output is wildly different from 5.1 output -- at least as represented by the Movie and Music apps. It's worse than the ATV3 which I find just a bit annoying.


In any case the audio software in tvOS is a work in progress. The last update (9.1) seems to have broken AAC vs AC-3 handling in my local library and the previous Subler based work-arounds have stopped working (for me).


For now Apple appears to be "devoted" to constant gain management which means that:

1) any bit stream input is decoded for said management and then possibly re-encoded.

2) direct access to low level outputs is "prohibited" although I suppose a careful reading of the developer docs would be required to completely sure.

Dec 15, 2015 12:41 PM in response to guygadvoir

I can appreciate the need to have changes in strategy from time to time, and have a long range view, but if you aim to improve on something why do it at the expense of breaking something that works as it should? To me, it looks like the focus was getting the ATV into the app ecosystem, and someone dropped the ball on one the fundamentals, which is good quality audio.

Hey, no argument here. I gave up playing with AAC and PCM multichannel when TV began supporting Dolby Digital alternative track encodes. I only brought this up as a possibly reason for Apple to "try and fix something that ain't broke already." (I.e., can't see any other reason for dropping a viable "passthrough" workflow in favor of a "multichannel decode to PCM" output strategy unless it plans to add future support for currently unsupported audio compression formats.) Even then, you'd think they'd keep the already proven bitstream passthrough device workflow. While I agree there may have been a push to rush the product to market, it does not explain the continued degradation of features that worked in previous tvOS and TV IOS releases—like allowing users to switch manually between AAC and AC3 audio tracks, passing all AC3 track audio to the receiver and only transforming non-DD/DD+ 2.0 audio to "Stereo" PCM, not requiring chapter track language associations, etc—which would hopefully restore proper LFE and DialNorm playback, as well as, correct "active" matrix decoding of "older" AC3 audio content. Who knows, maybe it would also cure the common cold.


Sorry if I seem to be repeatedly "harping" about the same things over and over. While I don't see the drastic changes in audio quality that some report, it does offend my sense of propriety that I have wasted almost a decade encoding and re-encoding thousands of files to ensure QT 7, QT X, IOS device, and now tvOS compatibility only to have Apple decide, over the period of a few weeks, not to play that content as it was originally encoded. I collect video content spanning a 9 decade period and want them to accurately represent the periods from which were taken—from the oldest black & white to latest 3D color video with audio ranging from mono to stereo, as well as, the changeover from early matrix multichannel to current DD and/or DD+ compatible equivalents of the latest discrete sensory multichannel formats retaining, as you said, "good quality audio."


Anything is possible through software, so why not add an option in ATV4 settings for no-frills pass-though so things will work just like the previous generations of devices? Surely they must know there are millions of customers with AVR home theatre systems that would be first in line to upgrade to the new ATV? Imho Steve Jobs could force things on consumers successfully because he obviously and meticulously thought things through. Nowadays, that probably happens less...

You're preaching to the choir here. And what's to add? Simply restore the already proven functionality. Unfortunately, Apple seems more interested in planning changes 2 to 3 updates into the future and less concerned with intermediate problems caused by such transitions—i.e., keeping secrets which might otherwise prepare users for such sweeping changes that suddenly seem to appear out of nowhere. If this is the result of a lack of meticulous forethought, then I agree with you.


You're right about different apps playing content differently. Have you tried using Infuse Pro? It does appear to play AC3 and DTS content quite well.

No. Just spent the last several hours playing with it. Was delighted with the ability to automatically pass DTS or AC3 audio directly to my AVR for decoding—and this includes the proper playback of AC3 1.0, 2.0, 2.1 audio with or without active matrix encoding. (However, AAC 1.0 is still output as 2-channel audio.) Also liked being able to link my entire video library (both BD/DVD source files and iTines managed library files) to a single player app. Only major complaint was that, even with the A8 chip, the TV4-InfusePro combination can sometimes stumble when playing video content in the 20-30 mbps range. Previously tried the Plex player which had smoother playback but this was likely because it performed on-the-fly conversion to IOS/tvOS supported formats resulting in more conservative data rates. Not totally satisfied with any single player at this time but, in combination, they demonstrate features I would like to see in a single app.


In any case, thanks for mentioning InfusePro. Am running half a day behind in adding new releases to my library but it was worth time and effort to find another alternative player that still properly supports my iTunes file encodes, as well as, adding a native DTS support workflow.

User uploaded file

Dec 15, 2015 1:03 PM in response to guygadvoir

Hello, I have the same problem PCM only, nevermind if I change to Surround, stereo or auto, is the same.

My ATV4 is properly setup to my AVS Yamaha, input, HDMI wire, etc, in fact I have no issues with my Blu-ray, Cable and Satellite Box.

My Blu-ray is an older Panasonic who comes with Netflix software. Via HDMI I can get DD 5.1, but saddly from the Apple TV4, I can`t, that means the problem is the Apple TV 4, or the TVOS software..

I have to say, this is a simple issue who needs to be solved by Apple ASAP, not the next year.

Dec 15, 2015 4:37 PM in response to guygadvoir

guygadvoir wrote:


Have you tried using Infuse Pro? It does appear to play AC3 and DTS content quite well.


I'd heard about this but assumed it was just another player even though it was from FireCore but given the comments I tried it and based on a sample of one* Infuse 4, unlike Plex, is either bit streaming or is able to set up the encoder to preserve dialog normalization. I'll hope it's the former.


*using the Plex server as a DLNA provider

Dec 16, 2015 8:37 AM in response to Community User

I have both installed and running, the problem still in the APTV4

In the case of Infuse Pro, did you remember to reset the default playback settings to "Dolby Passthrough" and/or "DTS Passthrough" as needed and does the file you are testing actually have a multichannel audio track selected for playback. As to Plex, it performs "live" conversion of the source file if needed but I believe it uses the TV4's global Surround output mode setting and so is still subject to certain problems while Infuse Pro bypasses it and the various multichannel problems associated with it.

User uploaded file

Dec 16, 2015 12:36 PM in response to Jon Walker

I've noticed the same issue with InfusePro during playback of some BD/DVD source content, however i assumed that may be due to the 100mb ethernet (Thank you Apple) i use on the ATV4. I have a 1GB ethernet switch to move data between my Tv, NAS, Receiver, and ATV3 and 4, which i prefer to use since wifi still isn't the most reliable means of network communication when it comes to streaming hi-def content. I had not considered the ATV4 hardware as being the bottleneck so you may be on to something there...

Dec 16, 2015 1:20 PM in response to bodosom

With InfusePro, It appears to be bit streaming, without the 'constant gain management' which you mentioned earlier. Of course its still early days and i hope to put the app through its paces with more content after the holidays.


If, as you mention "any bit stream input is decoded for said management and then possibly re-encoded", then i'm sorry to say, the ATV4 product is not going to revolutionize tv, its a bleeping disaster.


On the other hand, if apps like InfusePro are performing a bypass, then its some consolation we at least have access to our offline content libraries and can view and hear them they way they should. I for one am longer buying anything off iTunes until this wrong is righted. Why should I pay for a service which is sub-standard? Hopefully, when things start to impact their bottom line, saner heads will prevail.

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Apple Tv4 dolby surround is broken

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