Not able to output 5.1 sound through mdp to hdmi to tv

[darthcorey]

So i got the mono price Mini display port to hdmi adaptor. and it works fine. So i hook up a mbp that was bought in late 2010 so it carrys audio over mdp, and i get sound fine, but i am pretty sure its only out putting stereo. How do i get to be able to simply pass through the AC3 or DTS audio file for my receiver to decode? I think my computer is turning it into stereo and then out putting the audio as stereo instead of 5.1. And when i go to Audio/Midi setup all the options for anything but stereo are whited out so you cant select them for the hdmi audio connection. So i am confused? How do i make sure i am getting 5.1? I have made sure i checked to make sure the files i have are 5.1 and not stereo. I am running snow leopard 10.6 with the latest version of vlc.

Any help would be greatly appreciated!

[fkuehne]

Normally, I'd tell you to check the setting "Use S/PDIF when available" in VLC's preferences ("Audio" category). However, this option is reportedly broken in Mac OS X 10.6.8 due to an updated kernel extension. Since this is a part of the OS, there is little we can do about it at the moment.
Feel free to try the option though

[darthcorey]

So just to clarify, that option normally would instead of transcoding the audio into stereo, it would simply send the raw digital audio to my receiver, correct? Also i noticed there was an update for VLC recently since this post, does the newest version fix that? Thanks for your help. I really wanna be able to get surround sound from my computer.

[fkuehne]

Regrettably, that issue wasn't fixed in the public 1.1.11 release, but in last night's nightly build, which is available at http://nightlies.videolan.org/build/mac ... l/?C=M;O=D. Except for this fix, there are no differences to the actually released version.

[ramri]

Hi, just came across your post via google as I had the same issue.
I have the same exact config as you and what works for me is reverting back to 1.1.10 since this version still carries a third option in audio>audio device (HDMI encoded output). I get surround sound on all DTS and AC3 soundtracks in mkv containers that way.
Works on Lion too (been a tester since march, the problem exists there too, so the issue might have been inherited.
Hope this helps!

O'm still having trouble with mp4 files though, no idea why, but they're the only ones that keep giving me stubbornly stereo sound.
Any help would be greatly appreciated!

~R

[darthcorey]

Do you have a link to 1.1.10 cause i cant seem to get to it. Always DL 1.1.11. Also will the new mac os 10.6.8 suplemental update fix some of this? It said something about fixing an issue with audio over MDP and HDMI.

Thanks!

[chelgrian]

Do you have a link to 1.1.10 cause i cant seem to get to it. Always DL 1.1.11. Also will the new mac os 10.6.8 suplemental update fix some of this? It said something about fixing an issue with audio over MDP and HDMI.

10.6.8 + supplemental with the nightly VLC build from 1.1-branch-intel64-20110726-0210 works. The supplemental patch on its own doesn't fix any of the bitstreaming issues with VLC but may fix the optical and HDMI outputs not working at all on some macs, anecdotally some Mac Minis. I can't test if the VLC update on its own fixes the problem for macs where 10.6.8 doesn't break the optical and HDMI out as I've got no unpatched 10.6.8 boxes left. I've not been able to test on 10.7 yet.

I presume once enough people have tested this then a 1.1.12 will happen.

[ramri]

darthcorey, if you still wanna go /w my older build version, you could download the build from june 16th -it's the one I use up to now.
http://nightlies.videolan.org/build/mac ... 6-0210.zip (Assuming you have a 64 bit processor) else pick the same build for 32's from the same directory.

Chees, R

[fkuehne]

Dolby and DTS audio output is fixed in tonight's nightly build for Mac OS X 10.6.8 and 10.5.8. It can't be fixed for OS X Lion because of a bug in the OS, which needs to be fixed by Apple.

Note that there may be problems in the current builds when switching directly from Dolby to DTS tracks and vice versa.

[ramri]

Thanks for the effort, let me know if I can do something to press Apple into pushing the fix.
In the meantime, for Lion users: I still get moderately positive results by using older versions of VLC for most of the common encoding formats.

[ramri]

Oh the irony, XBMC, allegedly using an API from ages ago works perfectly in outputting most 5.1 streams in Lion, even those where Movist, VLC and MPlayer are failing me now. So up until this issue is fixed, I'd advise you to check that out.