Does 7.1 surround audio work on Mac? - AVS Forum
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post #1 of 6 Old 12-12-2012, 03:04 PM - Thread Starter
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So I have tried more or less everything now, it seems. VLC, Plex, XBMC, MPayerX. I just can't make the rear speakers output any audio. I have tested that they work in OSX, by sending white noise to them with the MIDI Setup, but I can't make any video stream work with more than 5.1.

Has anyone else succeeded? If so, what media player did you use? Is there a good test file for this online that I can download?

All comments are welcome!

Best regards,
Christian
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post #2 of 6 Old 12-13-2012, 06:36 AM
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What files are you trying to play and what kind of "7.1 surround audio" do they have?

If you're talking sd video sources, they are 2.0 or 5.1, DTS ES or NEO 6 or ProLogicIIx are usually matrix functions of your AVR expanding sound out into all your speakers and don't really have anything to do with your Mac or its settings.

If you're talking about Dolby TrueHD or DTS HD from blu ray rips, most here already know it's best not to try to play the actual HD track in OS X...asking a software player to downmix that in real time to something supported in OS X can lead to problems with the software player not putting the channels in the right place. It's been a quirk that the developers of those players have always had to deal with. What most of us do is let MakeMKV extract the DD or DTS core track, which is almost always 5.1, and simply play that, which players like XBMC usually have no problem with. Your AVR should light up with DTS or DD 5.1 if it is properly passed through and if you then want to expand that to your remaining two speakers you usually can do that by changing the surround setting on your AVR.

If you've converted the HD audio to FLAC or LPCM those are different animals, there's no agreement among the players or Handbrake or MakeMKV about how to handle that as far as setting channel order or re-ordering channels is concerned, that's all still in flux so expect some inconsistencies. What doesn't work right in Plex, for instance, may work just fine in XBMC.

If you haven't tried it yet, re-rip a disc with MakeMKV and don't retain the actual 7.1 HD audio track, just extract the core, then see how that plays in XBMC and what your AVR can do with it. In an ideal world, you should be able to rip and retain the original Dolby TrueHD or DTS HD track and then your player would automagically know how to extract the core when needed. I still don't think we're there yet, hence why it might be more prudent letting MakeMKV or Handbrake do it for you first.

Which Mac and AVR you have, which OS and player versions, whether you connect over HDMI and/or optical, all can make a difference in what you're able to achieve.
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post #3 of 6 Old 12-13-2012, 07:49 AM - Thread Starter
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Thanks for the answer! I'll try and answer your questions one by one.
Quote:
Originally Posted by chefklc View Post

What files are you trying to play and what kind of "7.1 surround audio" do they have?
One of the files that I use a lot for audio testing is this 7.1-channel audio check that can be downloaded online. It's an m2ts file with DTS HD-MA. It's a bit of a hassle, but it is called "DTS HD-Master Audio Sound Check 7.1 (Lossless)" and you can get it here: http://www.demo-world.eu/trailers/high-definition-trailers.php .
I have tried this file with XBMC on my Bootcamp partition and it plays just as it should with all 8 channels.

Quote:
Originally Posted by chefklc View Post

asking a software player to downmix [Dolby TrueHD orDTS MA] in real time to something supported in OS X can lead to problems with the software player not putting the channels in the right place.
Yeah, I think this is related to VLC and MPlayerX when the MIDI settings indicate 8 channels. I know that VLC doesn't yet officially support 7.1 and I'm guessing it's the same with MPlayerX. Remapping the channels is a small problem and can be done with the MIDI tool.


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Originally Posted by chefklc View Post

What most of us do is let MakeMKV extract the DD or DTS core track, which is almost always 5.1, and simply play that, which players like XBMC usually have no problem with.
Actually, XBMC and VLC can extract the core track just fine. That way I get 5.1 audio. The problem is that I would like to have 7.1 audio, something I know is supported by
- XBMC Window port
- My hardware
- My AVR
- My media
But maybe not OSX?
Or has nobody made a 7.1 media player for Mac yet?

So I guess I'm back to my original question; Has anyone anywhere been able to playback 7.1 on a Mac, using a media player and HDMI?
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post #4 of 6 Old 12-13-2012, 08:12 AM
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If what you're trying to play is a 7.1 DTS HD-MA track as you indicated, I already answered your question, it can't be played on a Mac in OS X. What can be played is the 5.1 core DTS. Send that to your AVR and then let the AVR matrix sound to those other two speakers.

Your only other option in OS X is to convert that 7.1 DTS HD-MA track to 8 channel LCPM ahead of time, which then can be passed to your AVR over HDMI with either Plex or XBMC, but it might be tricky to get all 8 channels in the right place. There have been previous threads here about this:

http://www.avsforum.com/t/1387397/br-lpcm-tracks-working-in-osx-w-plex-and-hdmi-mac-mini/0_40

Also, for any blu ray rip with Dolby TrueHD, Plex should be able to transcode it in real time and output LPCM 7.1 to your AVR.

Hope that helps.
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post #5 of 6 Old 12-13-2012, 09:34 AM - Thread Starter
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Thanks for your answers, and the tip about Dolby TrueHD, I'll check it out!

I wouldn't have anything against re-encoding DTS files if that's what it takes. But if you read the last posts in that thread you linked to, you'll see someone saying that not even PCM will work on Mac. You'll also see one of my posts where I say that can't figure out how to re-encode my files biggrin.gif

So as far as I know right now there are three ways of re-encoding DTS to PCM:
Handbrake, that you mentioned. I've tried it but with little success.
MakeMKV (I have never tried this, has anybody really made it work?)
Clown_BD (As you can see in the thread previously linked to, I can't find any settings to make PCM with it)

So I'm still a bit in the dark. (Read: It's pitch black here at Christian's smile.gif )
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post #6 of 6 Old 12-13-2012, 10:20 AM
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Quote:
Remapping the channels is a small problem and can be done with the MIDI tool.
Quote:
Actually, XBMC and VLC can extract the core track just fine.

I think you'll find, the deeper you get into playing back blu ray rips in OS X, that both of these approaches will cause you problems. You really don't want to go into AudioMIDI very much and mess with re-assigning output channels because the files you're going to play can be very different, they've been ripped, extracted, down mixed and encoded differently...players approach audio differently...and even if you eventually settle on one player for all your viewing needs, the sources of your files can vary tremendously. Most of us here recommend that you let your player, say XBMC, interact with Core Audio and AudioMIDI unchanged, that way when you have an issue, you know to go into the settings for XBMC to try to solve it. Let XBMC interact with CoreAudio according to Apple's APIs, at least at first.

And as far as relying on the player to extract the core audio in real time, again, my advice is long term you may not be happy relying on this, the players don't yet do this consistently well: how they extract the core and downmix the core varies...it's why channels get mixed up, why 2 channel is passed through sometimes instead of 5.1 or why the volume seems way out of whack on certain channels. Plus, it'll cause your Mac to run hotter and work harder than it has to. Let's say you don't really care about the latter, well, in my experience the former--real time downmixing of HD audio--will be problematic as you move beyond test files and get into actual rips of blu rays.
Quote:
So as far as I know right now there are three ways of re-encoding DTS to PCM

I don't re-encode to LPCM so I'm afraid I can't be much help to you. I'm perfectly happy with what MakeMKV extracts from the blu ray for me which I then let XBMC pass as encoded digital and/or then transcode with Handbrake for the aTV and iPads in the house. I don't even retain the HD audio when I rip with MakeMKV. You might want to poke around on the MakeMKV discussion forums because there now is an option to save HD audio to FLAC:

http://www.makemkv.com/forum2/viewtopic.php?f=1&t=5710

which you then might be able to do something with.

The strategy that's worked for me is for Handbrake and MakeMKV to put these tracks in our files ahead of time, your options are AC3 (ffmpeg), 6-channel discrete or AC3 Passthrough or DTS Passthrough depending on the source--you'll have to experiment to see which sounds best for you, yes it's extra work but it's more reliable in a home theater context if it is already there when it comes to players like XBMC and Plex. Of course, the main reason we're using Handbrake is to create a file that's also playable on the iPad and aTV, which admittedly you're not that concerned about, but having that second encoded digital or discrete multi-channel audio track right there can make life a lot easier for Macs in the home theater as well.

That's why I suggested you re-rip a title with MakeMKV allowing it to extract the core for you--then you could compare what a given player does 1) down mixing from the HD audio in real time versus 2) what MakeMKV did ahead of time. I'd be curious to see if there was any difference...

As you start troubleshooting, you probably want to start being very specific about your hardware and software, just saying "7.1" and "Mac" and "XBMC" is not enough, there's a lot of road to cover from Snow Leopard to Lion to ML and Dharma to Eden to Frodo, etc. Every update can break something or introduce a new quirk, many of us have learned the hard way to become pretty loathe to update once we've gotten something set up that works. For instance, if you're on the latest Mountain Lion and Frodo I can't help you because I'm still really happy on older versions, none of my home theater Macs, even though they are 2011 Minis, are on ML or Frodo yet. One is still running Dharma because it has been so solid.
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