Apple tv4 7.1 surround not workin

There's 2 issues going here. The first is the difference between PCM (Auto Setting) and DD/DD+ (Dolby Digital Setting). The second is having Apple TV select the surround track vs. the AAC 2.0 track in ripped media added to iTunes.

Regarding the first issue. It boils down to where the decoding of the audio track is being doing. If it is being done on the Apple TV using the Auto Setting then it send PCM to the receiver which is actually better quality than DD/DD+. Most people only feel the warm and fuzzies when the DD light goes on on their receiver but PCM is arguably better. On the other hand by using the Dolby Digital Setting Apple TV does NOT decode the audio and just passes the AC3 stream off to the receiver to decode if there is one. If there isn't one Apple TV encodes the stream there is into DD and sends it off to the receiver to decode. In either case the DD light goes on (even of there's only 2 channels) and people think they're getting better audio, but not really. Realistically speaking though most people probably can't hear the difference. Is Apple wrong? Is this behavior a bug? Not really but it is also not what is expected as most other consumer electronic devices don't behave this way.

Regarding the second issue. Almost all the conversion software people use to rip personal media to iTunes includes 2 tracks. An AAC 2.0 track for iDevices and a AC3 DD 5.1 track. For media purchased from iTunes internal "flags" are set so that Apple TV picks up the 5.1 track put iDevices play the 2.0 track. Most of this conversion software used (Handbrake etc.) does set not the "flags" in their output file. Apple TV and iDevices will both play the first audio track by default if there are no flags. Again, is Apple wrong? Is this a bug? On the one hand Apple TV and iDevices chose the correct audio track on iTunes purchased content. It's "home made" content that has the problem. One could argue that Apple should, in the absence of the proper flags, not default to the first track but to pick the "best" track (read 5.1 for AppleTV) for the device doing the playback. This can be fixed using Subler on Mac or MP4Box GUI on Windows but beware you may lose your meta data and adding the meta data back in after fixing the file my unfix the file.

Discoslap wrote:

Have you tried Terminator Genysi, also you should be getting dolby digital PLUS when playing 5.1 content so it doesnt have to be a 7.1 movie.

The new apple TV should be playing 5.1 dolby digital PLUS which is a higher res codec then just plain dolby digital.

Most Netflix movies are Dolby Digital Plus. It won't work regardless as we will have to wait for a firmware update.

I already returned my 2nd unit as Apple suggested i buy another one just in case it was device specific. Well I guess I have to run around trouble shooting when it just Apples crappy streaming device. I have been waiting for this thing just for the Dolby Digital PLUS codec and what a waste.

Any AV person here understands this, the 5.1 content can be matrixed to 7.1 and still be in Dolby Digital Plus so instead of searching for 7.1 just keep an eye out for the PLUS symbol on your receiver that you will never GET!

I am solely interested in getting DD+ 7.1 to function, but I understand and agree with what you are saying. I have no problems with DD5.1 and I dont care about DD+5.1 (which as you say is not working for me either). I've been in this game a while - head over to avsforum and look up my home theater build from many years ago - same user name.

Anyway, I am interested in files I can confirm are properly E-AC3 encoded, which I cant do with Netflix. I will need to buy a terrible movie to test Terminator Genysis via MediaInfo or some other tool and I dont want to do that.

I would like someone to point to a file they are sending to ATV4 that is proven to be E-AC3 7.1 (using mediaInfo or something similar)> Bottom line is those of us with 7.1 systems get nothing out of the rear channels regardless what is thrown at the ATV4 and AVR...b

If you have followed this thread all the way through you know we have covered every technical variation and detail, ** nobody has shown a file that is guaranteed to be E-AC3 7.1 encoded. iTunes has Terminator Genysis, but that hasn't passed the media sniffer test, Handbrake can't output a DD+ 7.1 file, I just tried a .mkv Dolby test file through the Plex app and even Plex says it's E-AC3 5.1. The source files can be found here:

http://www.demo-world.eu/2d-demo-trailers-hd/

Nobody can prove that Netflix is actually streaming 7.1....

So how do we really test the DD+7.1?????

Again, we have covered a lot of ground here so be sure you're up to speed before jumping in.

Agreed Disco. It just doesn't work properly. I've been messing around with A/V for a long time. Receivers, speakers, Apple TV's, Macs, etc. I never get Dolby Digital + no matter what settings I use. Have my old ATV3 plugged in currently. Everything working as expected. Stereo, Dolby Digital, Dolby Digital +, etc. all working properly depending on the source be it my own music or movie files, Netflix, HBO Go, etc. I'm with you.

I know. Plug your ATV3 back in. I had to. I got too frustrated. I'm waiting to see a software fix in an update or something. I really doubt the way it's "working" on the ATV4 is by design. ***** because I like the ATV4 and it has a lot of promise. I got the new one to continue to use it as I did the ATV3 (which obviously isn't working for us) and the faster processing, faster WIFI, new apps, new remote, etc. The audio issue is the only thing keeping me from using it but for me (audio/video junkie), it's a showstopper.

We'll see what pans out.

Using the Auto setting on audio out actually seem to produce correct surround sound on my system. Can it be that in the Auto setting actually makes the ATV4 do the decoding (irrelevevant of it being a 7.1 or 5.1 Dolby digital coded movie)?

Hello, this is what are my findings (already posted in other thread)

Just installed the Home Theater test App (thanks Bodosom).

When having the surround setting set to 'auto' the receiver detects 7.1 PCM input 3/4/.1.

THe App detects 8 speakers, so far so good!

THen however during the test all speaker signals are mixed up. Rear channels direct to subwoofer, left surround to center etcetera. Two out of 8 channels do not produce any sound.

The App hints to a problem of mixed signals. Workaround would be to set the Dolby Digital setting to 'ON'. However this setting does not exist in ATV 4.

when setting the ATV to surround mode 'auto', the App only detects 5 speakers.

HELP!

Roggamannen wrote:

Can it be that in the Auto setting actually makes the ATV4 do the decoding (irrelevevant of it being a 7.1 or 5.1 Dolby digital coded movie)?

I initially thought the ATV 4gen was decoding everything and sent PCM. This is because my AVR has both OSD and web interfaces and reported two different values for the input signal from the ATV 4gen. It's now clear that when Surround Sound is set to Dolby Surround an AC-3 signal is generated however the bitstream from a model ATV5,1 (ATV 4g) is not the same as the bitstream for the same input a model ATV3,1 (ATV 3g). The "dialnorm" meta-data has been removed which means it is modifying the bitstream. I don't know if it's possible to do that without a decode/encode step.

The critical part of this for this thread is that the ATV 4g is decoding everything in AUTO mode it's not possible to know what the original bitream contained. Since we have a report of rear surround data in Terminator Genisys we can conclude the data is there. I don't imagine we actually need to compare a disc version to be convinced that Apple is putting one over on us.

Despite the OP rather vehement assertions about this after you consider the possibility of multiple audio tracks and the ATV 4g picking AAC rather than AC-3 I think that

1) The jury is still out if there's are bugs relevant to this thread.

2) If there is a bug or bugs I'm sure fixes will be forthcoming.

3) If there isn't a bug Apple will change the way it works so to minimize support calls.

bodosom wrote:

... a model ATV5,1 (ATV 4g) is not the same as the bitstream for the same input a model ATV3,1 (ATV 3g).... Apple is putting one over on us.

sigh

That should say "ATV5,3" and "Apple isn't putting"

jvulto wrote:

@bodosom Good Analysis, thanks for that. Could you emphesise on how this relates to channels being mixed up when using that Theater App?

Buggy software. It would be nice if the developer fixed it but I think the presence of reasonable rear surround data in Terminator Genisys is sufficient validation that 7.1 and E-AC-3 are working.

Discoslap wrote:

Bodosom, please play terminator from Blu ray than try Apple tv4 and you will realize very fast it's totally different.

Reasonable content has been reported for the iTunes version.

You've done this comparison and found a difference you can attribute to improperly encoded E-AC-3?

In my case even if I was interested in buying two copies of a wretched movie for testing purposes and was willing to reconfigure my HT with rear surrounds I wouldn't be surprised if TrueHD sounded perceptibly different from E-AC-3.

Receiver surround mode: auto

ATV surround mode: auto

The home theater app does mix up signals but also two of the signals are NOT hearable.

When playing Terminator G in 7.1 sound track, all channels work correct (not mixed, I think) but back surround L+R NOT hearable.

In both cases the receiver shows as input signal: 3/4/.1

Home Theater app not being able to produce sound for two out of 7.1 channels seems like the same problem when playing Terminator G in 7.1.

The mixed channels thingy probably is a bug of the app itself, but the missing two additional channels does seem to be a ATV overall issue.

When playing Netflix content with DD+ also the two back surround L+R NOT hearable.