Apple tv4 7.1 surround not workin

It's funny because in auto surround mode on Apple TV it displays 7 speakers but plays 2 speakers. When I manually change it to Dolby surround on my Apple TV it will just play regular 5.1 Dolby digital and not the 7.1 Dolby digital plus.

Are your movies encoded with separate Stereo and Surround audio tracks? If so, you may need to manually select the "Surround" audio track if your file is defaulting to "Stereo" since the TV4 appears to only map active source channels when "forced" to output PCM by the "Surround Sound > Auto" option. Further, most AVRs seem to report channelization as 7.1— i.e., they don't all differentiate between "active only" and "active + empty" channels. TV4 audio "forced" to output as DD5.1 using the "Surround Sound > Dolby Surround" setting behave in a similar manner. Only selected audio tracks already in the targeted output compression format appear to be currently "passed through" to the AVR. In my case, I can only confirm this to be true for DD5.1 content since all of my videos are encoded with AAC and AC3 audio tracks.

Is the Auto setting working correctly? To me, auto implies it is going to choose the best audio output method for the content played. When its stereo vs. DD 5.1, I would expect it to output 5.1, yet it only outputs stereo.

This, of course, depends on your definition of how "Auto" is supposed to work and under your given definition, it is not working correctly. As I previously indicated, I do not have any PCM encoded video files so I cannot fully test what happens when 1-, 2-, 5.1-, or 7.1-channel source PCM audio is sent to an AVR in the "Auto" mode. I suspect it may work in a manner similar to the "Dolby Surround" mode for AC3 source audio but I cannot confirm it at this time.

Basically, the TV4 "Auto" mode forces output as 7.1 PCM audio with active source channels mapped to corresponding 7.1 PCM channels. My system reports all 8 (both active and empty) 7.1 PCM channels in the AVR display but at least one individual reports that his Onkyo system only reports the "active" channels in his AVR display. This mode may or may not "pass through" source PCM "as is" in the "Auto" mode but this is what I cannot test or confirm at this time. I suspect that Apple has now adopted 7.1 PCM HDMI—with its higher resolution audio specification—as its default output audio format and interface beginning with the TV4 and has "redefined" the functionality of the "Auto" setting. If this is Apple's new definition for the "Auto" setting, then I would say it is working correctly.

As to AC3 use, in the TV4 "Dolby Surround" mode I can confirm that non-AC3 tracks in my video files are forced to AC3 DD5.1 with active channels mapped to corresponding DD5.1 channels and that AC3 source tracks—when selected—are passed directly "as is" to my AVR. I.e., source audio such as AAC "forced" as AC3 output displays as "active plus empty" DD5.1 channels on my AVR while source AC3 audio tracks are "passed through as is" and are displayed on my AVR with channelization as originally encoded (e.g., as mono, stereo, or surround sound encodings).

Unfortunately, there seem to have been other player changes which appear to affect the automatic selection of the default track for playback as in a manner similar the the previous TV3.

I tried Auto and Dolby Surround on the ATV4 and changing settings on my Denon receiver. I plug my ATV3 back in and Stereo is always Stereo. Dolby Digital is always Dolby Digital using any apps, Netflix, etc. and my own media. Not happening with my ATV4. Lots of other people are reporting the problems in the Apple and Macrumors forums.

Which source track are you selecting? The TV3 can automatically select a disabled DD5.1 surround audio track when available along with an enabled AAC stereo track. The TV4 does not do this unless you make some modifications to the source file. Check to make sure you are actually playing the source track you want played in the mode you want to play it—e.g., select the AC3 5.DD1 surround audio track (and not the AAC mono, stereo, or PL II audio track) for "passthrough" playback in the "Dolby Surround" mode (and not the "Auto" mode which forces 7.1 PCM output of AC3 mono, stereo, or DD5.1 audio) if you want TV3-like playback.

Are you changing the ATV setting and the receiver setting?

No. I set my AVR (Pioneer) to the "Auto Surround" mode and let it automatically select which decoder to use (PCM or Dolby) depending on the TV4 output mode I am using. Since I normally use the TV4 for movie/TV playback, I normally use the "Dolby Surround" setting to passthrough AC3 audio in its original mono, stereo, Dolby PL II, or surround format. If I switch to music, all of which is in stereo, I normally let the TV4 convert the source M4A, Apple Lossless, MP3, or AIFF audio to AC3 stereo for playback through my AVR without having to make AVR setting changes even though the TV4 outputs the stereo over a DD5.1 connection—i.e., the C, RL, RR, and LFE (?) channels are empty. Alternately, I can switch the TV4 to "Stereo" mode and all music content will be sent to my AVR as stereo PCM and, once again, I don't have to make any AVR setting changes for playback but now my AVR correctly identifies the connection as stereo PCM.

The ATV4 is not passing through bitstream so your Pioneer should not/is not doing the decoding, the ATV4 is and sending the decoded signal for the Pioneer to distribute to the channels.

Okay. However, if this is true, then the TV3 and TV2 devices are also not passing through the AC3 bitstream since my TV2, TV3, and TV4 all play the same H.264/AC3 source content in the same way with the exception that I must either manually select the source AC3 track or modify the enabled/disabled and/or "fallback" track options so that all OS/IOS/tvOS players can automatically default to a desired and/or compatible audio track. I.e., my Pioneer decoder says it is decoding mono, stereo (with or without active PL II), or DD5.1 surround AC3 content dependent on actual content encoded in the original source AC3 track.

Regardless, you are correct in that there seems to be a problem here. Specifically, when using 7.1 (TruHD 7.1, DD+7.1, or DD AC3 5.1) I only get 5.1, regardless of ATV setting (auto or dolby digital). My AVR display will read 7.1 [PCM] when the ATV is in auto, but the rear surrounds are silent.

As previously noted on more than one occasion, I cannot test, confirm, nor deny any statements regarding 7.1 PCM encoded files since my only PCM files are AIFF stored music CD content with which I am not concerned here—this includes any questions of 7.1 source content being limited to 5.1 audio output. On the other hand, I don't see why you would be surprised that AC3 5.1 source content would be limited 5.1 channelization since this seems self-evident or implicit in the base proposition, As to empty rear surround channels in the "Auto" mode, I can confirm this when sourcing DD5.1 content and forcing output as 7.1 PCM in the "Auto" mode. Again, as previously noted, the fact that the TV4 can open 7.1 PCM or 5.1 AC3 HDMI connections to the AVR does not necessarily mean that it will "populate" all available channels—especially if there is no source data channel to be mapped to a particular output channel.

I am using various Dolby .mkv files converted to .m4v then imported into iTunes. My setup is ATV4>HDMI>Denon AVR>HDMI>Panny Plasma. The denon can handle all the codec mentioned in this post on its own, if it were allowed to! But its not, since the ATV doesn't pass through a bitstream but decodes and then sends a decoded signal.

I am using the same basic workflow to create iTunes managed M4V files sourced from BD. What confuses me here is the format you contend your TV4 is sending to your AVR. The "Auto Surround" (AKA "Stream Direct" and "Pure Stream Direct") setting on my system always defaults to the Dolby Digital decoder on my system when I play an AC3 audio track on my TV4 set to the "Dolby Surround" option correctly displaying the originally encoded channels and always defaults to the 7.1 PCM decoder (with corresponding "empty" channels for unencoded original channels) when I play the AC3 track in the "Auto" mode. So just what is the format of this "decoded signal" being sent to your Denon that is neither PCM nor Dolby Digital content? Your own test results confirm my own findings with regard to TV4 output received/displayed by the AVR. The only difference I see is that you contend that a source AC3 audio track sent from the TV4 in the "Dolby Surround" mode is unconditionally re-encoded as DD5.1 content. This is not true on my system. A mono AC3 audio track is received and decoded as mono AC3 content, a stereo AC3 track is received and decoded as stereo content, and an AC3 DD5.1 track is received and decoded as DD5.1 content.

I am not sure whee the breakdown could be here other than ATV or the .mv4 file format? Obviously, there is no "7.1" signal being distributed to all 8 speakers.

In re-reading your post for the umpteenth time, I'm beginning to suspect the problem may be in your TV4 playback workflow. You indicate you used Handbrake to create M4V files for testing. This implies the your files contain both AAC and AC3 or AAC and PCM audio tracks. It is unclear, however, which track was being tested for TV4 output nor did you indicate the number of channels decoded (actively played) by your AVR for each test. Since the TV4 does not automatically default to the "Surround Sound" track as the previous TV2 and TV3 models do, a question arises as to whether or not you manually selected a correct track for TV4 tests, and if not, whether or not you modified the enabled/disabled and/or "fallback" track settings to force the TV4 to automatically default to the surround sound tracks rather than the AAC tracks during tests.

my point was to just list for the sake of a test sample pool that no matter what I throw at it....the outcome is 5.1.

Still confused by the point you are trying to make here. You refer to a channel limitation (5.1) but fail to mention the source compression format or the TV4 output mode—both of which determine the scope of channel limitations and totally ignores the fact that, in the case of AC3 at least, when the source compression format is the same as the target output mode, the TV4 passes through the original data rather than unconditionally forcing non-AC3 audio content to AC3 5.1 output with or without empty channels.

As far as handbrake and multiple tracks, I encoded with a single track each time...did not include the standard standby core like ACC or something....for example.

Then I do not understand why your AC3 results would be different from mine or why you would conclude the that the AC3 content was not being passed through "as is" by the TV4. (I assume you tested mono, stereo, and active PL II, as well as, AC3 5.1 content to compare output with input content.)

Between this thread and the thread Im involved with on AVSForum its quite clear that we have a problem here....we are all just explaining it based on our own equipment/history/verbiage.....

So what exactly is the problem here? I have more than 9,000 files encoded with AC3 secondary audio tracks which play correctly for me on the TV4 at this time. Is this "problem" limited to 7.1 PCM playback? Or are you saying you have an AC3 playback problem also? Frankly, I am more concerned about the way the TV4 now selects the default audio playback track, the loss of chapter marker access, and the scope of Siri searches in my iTunes library.

Perhaps your AVR is misleading you, it seems some report/display the surround mode rather than the input signal just as my AVR foolishly reports MPCM as analog.

I am curious as to why you think it more likely that my AC3 audio track for my movie which output via the HDMI connection from my TV4 in the "Dolby Surround" mode is NOT being received as AC3—even though the AVR confirms the HDMI connection, automatically switches to the ""DD Digital" decoder, correctly identifies each active channel, and each active channel plays independent audio content through its corresponding speaker which is easily confirmed aurally by the user.

I readily admit that playing an AAC audio track using the same settings does create some anomalies in that the AC3 5.1 HDMI connection thus created is only mapped with audio to the Front Left and Front Right channels. Unlike an AC3 stereo encoded track which only displays its active channels on the AVR, a "forced" AAC to AC3 connection unconditionally displays as DD5.1 audio but can easily be identified as being a "forced" AC3 connection since the AVR will never display any LFE activity and the user can aurally confirm that the center and rear channels are empty. I assume this may be what you are seeing.

If I watch movie X with an AC3 soundtrack on my ATV3 my AVR (Denon 4311) reports Dolby Digital input (3/2/.1). If I watch the same movie on my ATV4 my AVR reports multi-channel PCM input (3/4/.1).

That is what I get if I try to play any AC3 track on the TV4 using the "Auto" mode—i.e., the TV4 connects with the AVR using a "forced" 7.1 PCM HDMI connection.

No matter what configuration or source I've used so far on the ATV4 I always get MPCM. The number of channels reported is a product of the ATV4 Audio mode and the source. The ATV4 does let me select between AAC and AC3 pass-through sound tracks but the result is the same MPCM.

AC3 "passthrough" is automatic on my system when I source an AC3 track in the TV4 "Dolby Surround" mode. (Am referring to real AC3 encodes here and not DD+ 7.1 audio tracks.)

I've speculated over on AVS that Apple has decided to go old-school and do the decoding in the ATV4 since they know they can send 8 PCM channels over HDMI while they can only speculate if your AVR can decode DD+. In this case they means the staff at Apple (the ATV4 itself should be able to tell if you can decode EAC3). The problem my speculation is the nature of EAC3 chips. If they are using EAC3 as a transport and decoding it in the box then they should be able to bitstream AC3 and EAC3.

I had assumed that AC3 and DD+ 7.1 would be passed through to the AVR for decoding and all other supported formats would be mapped to a 7.1 PCM HDMI connection with the AVR. Have no experience with E-C3 so I downloaded a WAV 8-channel sample file and tried to transcode it using Compressor. However, compressor would only allow a max 5.1 channelization. Not sure if I need an update or if this is the max limit for the app or my workflow was incorrect. Will have to look into this further later.

Sorry for the delay in responding. Was up until 5 AM and had a medical appointment first thing this AM.

No, Jon, you are correct; Compressor currently only has support for 5.1 channel output.

Thanks for providing this information. It undoubtedly saved me several hours of fruitless labor.

@all My working hypothesis is that the random, none-sensical symptoms we are all experiencing with surround playback is a result of the Apple TV 4 corrupting the Dolby Digital 5.1 data stream. I have been working hard to get this resolved with Apple support and your forwarding your symptoms and set-ups to them via feedback or bug reporting would be extremely helpful in getting these issues resolved!

Agree this would be a likely scenario for the "random, non-sensical" pseudo-AC3 connection anomalies but I don't use a "forced" workflow to play my content. In fact, I suspect the use of a forced or pseudo-AC3 workflow by not resetting the default audio track of each newly opened file is what is causing the "corruption" issue for a majority of DD5.1 users since I seriously doubt Apple has actually integrated an AC3 encoder into the TV4.

Jeff P., Author, Surround Speaker Check app for tvOS

Thanks for the reference. I downloaded the app since it was free and its test results mirror the DD5.1 test results of my own DD5.1 content. I.e., failure to reset source track selection results in anomalous pseudo-AC3 playback. With the correct AC3 encoded track selected, your app's graphic display matches my AVR graphic display and individual speaker activity. The only thing I might recommend would be to look into changing the Test/Sample file settings to automatically select the DD5.1 audio track so it will be compatible with all OS, IOS, and tvOS players rather than allowing the TV4 to default to the stereo audio track as it currently does. Unfortunately, I'm not sure if the current default track selection algorithm used by the TV4 is a permanent change or not. While the process of changing a few random files is simple, it is not a project I would start arbitrarily for thousands of files before knowing more.

PS. I'm fairly certain that Apple TV 4 is not performing any of the actual surround decoding.

I agree that it is much more likely that Apple's intention is to carry over the same processing routines pioneered for earlier TV devices but updated to support a newly included DD+ 7.1 content option—which seems to have created entirely new "bugs." My only reason for initially posting here was to point out the change in the "Surround Sound > Auto" setting functionality of the TV4 as compared with earlier TV devices. Instead, I became embroiled in an argument questioning whether or not DD5.1 content is stilled supported on the TV4 and whether or not it is actually still being "passed through" for decoding by the AVR. For me the answer to both questions is still a resounding "YES!" Since I'm not involved with either DD+ 7.1 or "pseudo-AC3" workflows, I have nothing more of value to add—something I'm sure will please at least one other contributor to this forum topic.

Again, thanks for your post, Jeff. You are a gentleman. Both the information and app were helpful and appreciated. I look forward to a final solution to this issue even if I don't use such content myself and hope/assume you will then be updating your app to include a 7.1 audio test routines for the TV4. Best of luck.

Unfortunately, it is up to the OS to detect the AC-3 (or EC-3) track and substitute for the AAC stereo track whenever possible. AFAIK, there is no way for media producers to "force a default" on our end, so we're at Apple's mercy to provide a quick and reliable update to solve the problem... The Apple TV 2 and 3 models were pretty rock solid on delivery AC-3, so I'm confident they'll get there. How soon, though, likely depends on the amount of user feedback they receive regarding the issue.

Why not give the tvOS a hand here. If you have the inclination and time, try the following. Use an app like Subler to reset or re-mux a modified copy of the original file with the enabled AAC track disabled and the disabled AC3 5.1 track enabled. Not sure what Subler is doing here since the QT 7 Pro "Properties" window still insists the enable/disable settings are unchanged, but your modified file should now automatically default to the AC3 track when opened in the TV4 "Computers" app player and automatically play correctly if you are in the "Dolby Surround" mode. In addition, the files continue to open and play correctly on TV2 and TV3 using the AC3 5.1 track and QT 7 and IOS mobile devices continue to open using the AAC track while apps like QTX and VLC open with the AC3 track selected but only play 5.1 audio if you have a decoder connected to your computer. It you want to hide the AAC track from your TV4, you can also try the "Fallback" option setting to designate the AAC track as "fallback" for the AC3 track. Unfortunately, I haven't had time to test this latter modification in all other players yet as I am running about 4,000 files behind in "proofing" my library conversions with more media scheduled to arrive today in the mail.

Yes, that would be fun! Perhaps after the dust settles a bit...

Will be looking forward to it...

E-AC-3 is a superset of AC-3. You can encode 1-15 channels. Given an E-AC-3 object how would you get it into the ATV4? Or is there an app for that?

Yes, I did research the extended capabilities/features of the format but not its technical encoding specification differences with standard AC3/A52. Wanted to create and test some 7.1 file content but find none of my current Mac apps can do this. Can you recommend one?

I don't quite follow the discussions above, but would you agree that changing the setting to Dolby surround at least sends the correct Dolby Digital 5.1 signal to the receiver?

Yes, if you are actually playing DD5.1 track content. It works fine for me but many users still insist theirs isn't working. I suspect that, in many if not most cases, the problem is related to the user's "track selection" for the file being played. Unlike older models, the current TV4 appears to unconditionally reset the track selection each time a file is closed and opened. This means that if your file is encoded with more than one audio track, the primary enabled audio track is automatically reset as the "default" audio track each time the file is opened. For those of us using H.264/AAC/AC3/Chapter M4V or MOV files, this means a file will reset to AAC stereo each time the file is opened (if it is not manually recoded to open the AC3 track by the user) and an AAC track playing back in the "Dolby Surround" mode produces anomalous "pseudo-AC3" AVR indications for most users—e.g., the AVR indicates it is playing DD5.1 content but only the FL/FR speakers may actually be playing.

Jon Walker wrote:

Since I'm not involved with either DD+ 7.1 or "pseudo-AC3" workflows, I have nothing more of value to add—something I'm sure will please at least one other contributor to this forum topic.

...I don't use such content myself and hope/assume you will then be updating your app to include a 7.1 audio test routines for the TV4. Best of luck.

Oh well...

This may or may not be related to the issue I've noticed in a different thread:

https://discussions.apple.com/thread/7319516

I've noticed a few apps, Trailers and YouTube, only output in Stereo.

My settings are default, and therefore Auto. I'll try forcing to DD and see if there is a diff.

I'll also try some purchased movies for 7.1, as I've only noticed 5.1 decoding, which is the same as ATV3.

Is the Auto setting working correctly? To me, auto implies it is going to choose the best audio output method for the content played. When its stereo vs. DD 5.1, I would expect it to output 5.1, yet it only outputs stereo.

Wondering if this is not completely developed or is a bug.