Only 2.0 option on HDMI iso 8 channel

Question

Spawnreaper Author

Level 1

9 points

Only 2.0 option on HDMI iso 8 channel

Mac mini late 2012 model Sierra 10.12.5

If I select more then 2 channels in the midi setup app (want 8 channel) I get no sound.

The both "encoded digital audio" options are greyed out.

Apple specs show that this model does support 8 channel output though HDMI but its not working.

Previously my Plex media centre was able to bypass the midi setup and just pump it through straight to my receiver that would handle the decoding. Now my receiver shows its only getting 2.0 pcm audio.

Maybe someone at apple could explain why there are so many articles describing the problem but apple is not fixing or replacing the app.

Mac mini, macOS Sierra (10.12.4), Late 2012 model

Posted on Jun 5, 2017 8:03 AM

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Answer 1

MJonline

Level 1

8 points

Jun 5, 2017 9:01 AM in response to Spawnreaper

There seem to be countless questions about getting 5.1 ~ 7.1 audio through a Mac.

And for good reasons, apple seems to keep things hidden in the dark.

I found a solution that actually works. You have to go into the Terminal app...application/utilities/Terminal.

Type this: defaults write com. cod3r .a52codec attemptPassthrough 1

When you start a movie from iTunes, click on the speech bubble at the bottom of the screen and check prefer AC3 Passthrough.

You will be able to send a digital stream to the Optical Out and be decoded by the AVR or pre/pro.

or what I do, go into midi audio and select hdmi or multi-device (hdmi ✔ and Dirac✔), format 6 ch 24 bit 48khz or 8ch 24bit 48khz, depending if the audio is 5.1 or 7.1. In this way, I can send the signal thru the Dirac multichannel room correction. It does sound superior to the digital stream sent to my Oppo105D and thus no room correction.

And I find the Dirac is superior to the autoEQ in the AVR I used to use.

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Answer 2

MJonline

Level 1

8 points

Jun 5, 2017 12:11 PM in response to Spawnreaper

I have no experience with Plex. But the fact Apple says a Mac will pass AC3/DTS is a half truth. It's only via iTunes, as far as I can tell. Getting 5.1 from Netflix is not possible because of the browsers use of Silverlight or HTML5 video players. I tried a outboard 5.1 soundcard that did not work at all.

Using an 🍎TV as a source, will give you 5.1 or 7.1(🍎TV 4).

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Answer 3

Spawnreaper Author

Level 1

9 points

Jun 5, 2017 12:37 PM in response to MJonline

MJonline, My media collection is too large in too many deferent file formats to convert to the apple standard. iTunes and Apple tv only support there own file formats. Plex is way more compatible, user friendly and easier to manage then its apple counterpart. I know the last apple tv does offer a plex app but it nags me a bit that my setup did work a week ago. The mac mini can do it. There must be a solution to fix this again.

Having said that, Apple should correct a bug if there is one. And this, this is a very old bug.

Besides that. Apple tv only has 10/100BASE‑T Ethernet and does not support any DTS versions.

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Answer 4

MJonline

Level 1

8 points

Jun 5, 2017 2:38 PM in response to Spawnreaper

I've used the optical out, with the midi set to encoded digital out. The audio stream in the movie has to be checked prefer AC3 pass through.

If I want to output 5.1 via HDMI, I uncheck the pass through. This is where I'm using the Dirac RC.

When I typed in the Passthrough script in Terminal, I had no problem, at all. But I'm also not using any 3rd party software, except the Dirac.

As for if there is a bug, I don't know that there is.

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Answer 5

Spawnreaper Author

Level 1

9 points

Jun 8, 2017 2:49 AM in response to Spawnreaper

I seem to have figured out the problem. ARC was active between tv and receiver to let one device turn of the other.
Searching forums I stumbled on this comment:

Most (if not all) TVs are stereo and so will accept only 2ch from HDMI. ARC only transmits stereo audio because of copyright issues. Check your TV's manual, it will mention this in the description of ARC.

Turned it off and bam, midi audio on 8 channel, but now with audio.
Still not sure why the old setup worked before and suddenly stopped working.
Down side is turning off/on tv and receiver separately. I anyone has a work around for that I am all ears.

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