VLC mixes up my 5.1 sound channels

[Serious]

Hi !

I recently bought an external soundcard (M-Audio Sonica Theater USB) for my iBook to connect it to my 5.1 sound system. Since then I often wondered why the people at the studios would arrange the audio channels in such a strange way. I watched quite a few DVDs in the last weeks, and it's always the same problem :

My rear left speaker puts out all the speaking - so it's the channel for the center speaker. My rear right speaker is silent. The center speaker says very few things, but it sounds like one of the rear channels. The sub and the front speaker output seems to be okay.
Here are a few things I wanna say :

- This is the problem with all of my DVDs, not just with one or two discs.

- The Audio/Midi configuration is set up correctly for use with a 5.1 system. The channel-samples work correctly, which underlines the next point...

- The problem does not lie in the way my external soundcard is connected to my speakers. I checked the connections about 20 times.

- I already removed the VLC preference file. Didn't help :/

- Restarting the iBook doesn't change anything either.

- I use VLC 0.8.2 with Mac OS 10.4.2 on an 800 Mhz iBook G4, 640 MB ram.

So... the channels work fine with the M-Audio software (of course the up-to-date version 1.6) and the Audio/Midi configuration. This makes me believe that VLC is the problem . I tried other players like Mplayer, but I just got stereo sound. Are there any other players which support analog surround sound output, so I could check if they work properly ?

Help

[The DJ]

No, it's the M-audio drivers that don't communicate properly how they are setup. Your answer is in the VLC 0.8.2 README.MacOSX.rtf file

12. Multiple sound-devices and multi-channel sound?
Look at the Audio->Audio Device menuitem.
- For analog audio output, you should change your speakerlayout in the Audio Midi Setup utility. The program is located in /Applications/Utilities.
Select your audio device in "Properties For:", then click the "Configure Speakers" button. Choose "Multichannel". Even if these settings are correct, you should change them and click "Apply", then change them back and again click "Apply". This is important, otherwise VLC cannot reliably detect which speakers are connected.
- Make sure your device surround configuration is not set to emulate surround output. M-Audio for instance defaults to using SRS surround sound emulation in multichannel setups. You should change this to "None/OpenAL".
- We are in a transitional phase for our Mac OS X audio system. Therefore it is currently not possible to use Digital audio without changing a Preferences setting. The setting is in Audio->Output modules. Change this from default to "CoreAudio output". This is the module that was also used in previous versions of VLC. It has several issues with Analog audio, but it also supports Digital audio, which the new module does not yet support. You should ONLY use this module for Digital output.

DJ

[Serious]

I read the readme file before I posted my problem because you mentioned it in the "5.1 canals inverted ?" thread

That's what I meant with

The Audio/Midi configuration is set up correctly for use with a 5.1 system.

But okay, I'll try it again...

*.......*

...nope, the center channel still comes from the rear left speaker. One more time...


*.......*

Still doesn't work. I changed the setting back and forth, clicked "Apply" etc.

Thank you, so far

Any other ideas ?

[The DJ]

Well i have the same Sonica Theather and for me it works. So i don't know then.

[Serious]

Howdy, neighbour

Okay then. You don't think a different player could help, do you ?

Which players can output analog 5.1 sound, besides VLC ?
I thought of MPlayer but I only get stereo out of that thing...

[Guest]

my presonus firebox does simlar things. in the audio midi setup i have to set the stereo channels to output 5 and 6 in the audio speaker set up.

after that, VLC played correctly.

You may have to spend time configuring them. Each time you change the configuration you must close VLC and restart for the changes to register in VLC.

Thanks for questioning because you helped me find a solution.

[Guest]

continuing

each time you change the speaker setup in audi.midi, to register tha changes you have to close and reopen vlc for vlc to use the changes.
set the output to coreaudio

[Serious]

Alrighty, I'll give it another try when I get home next week. I'll post the results

[Serious]

Well, I'd say I checked every possible constellation

I opened the Audio/Midi configuration, set the output to 5.1, clicked "Apply" about ten times, closed the windows. Then I reopened it to see if it really saved the settings - and I'm not sure it did :

In the Audio/Midi window it says "44,100 Hz, 6 Channel, 16 Bit", but when the speaker configuration window pops up it's always set to "Stereo". Is this normal ?

Anyway, I set it to 5.1 clicked "Apply" again and open VLC to play one of my DVDs.

I tried that procedure with the VLC output switched to both "Standard" and "CoreAudio" - it didn't make any difference. My channels are still mixed up. Of course, the "Surround Sound" in the M-Audio panel was set to "None, OpenAL" all the time.

Any other ideas ?

[Serious]

No, it's the M-audio drivers that don't communicate properly how they are setup.

So this could be solved by M-Audio, if the chose to release proper drivers, right ?
Unfortunately, I don't understand too much of these developer-level things.
What could I tell the M-Audio Support ?

That the Sonica drivers simply "don't communicate properly" with the rest of the system ? Do you have a more detailed, but still understandable version of this problem ?

[The DJ]

M-audio already knows. I tested VLC with their device for them. They are working on it.
And you need to change the Channel order/speaker assignment, not the dolby setup. You use the tester buttons. Take a dropdown button, set left front to something else. apply. Now restore the speaker assignments to the channels again and again apply.

[Serious]

I tried that, too, but it doesn't have any effect on the channel output.

I hope M-Audio is gonna release those new drivers real soon - this is driving me nuts

Thanks for the support, DJ !

[ipod30giga]

So this is a driver issue? I have a set of Bose Companion 5 speakers, which are 5.1, and i have the exact same issue - Center plays out of the left rear channel. Everything in Audio MIDI Setup is set correctly (I'm running VLC 1.1.3 for Intel 64bit on OS X 10.7)

[fkuehne]

Regrettably, a known issue on OS X Lion, which I can't fix at the moment due to the lack of a testing device. I hope to get one shortly though.

[fcp50]

Hi
I have exactly the same problem of ipod30giga. I'm running VLC 1.1.11 for Intel 64bit on OS X 10.7 and a macbook pro (early 2011) using an iWires HDMI adapter

[mscofield]

Any updates on this? I have the same problem with my new MacBook Air.
It's so weird, hearing the voices on the rear channels.

[japumpy]

I have a new MacBook Air with a Moshi HDMI connector to my Sony AV amp. The centre channel is playing from the rear left channel. Is this a VLC issue or a Lion issue? I'd appreciate some guidance on this please.

Cheers!

[Muntyhoven]

This is also being discussed in the following two threads:

viewtopic.php?f=12&t=93173
viewtopic.php?f=12&t=91767

It appears still to be a problem even with the nightly builds of VLC and with the recent OS X 10.7.1 upgrade. AFAIK it was hoped that OS X 10.7.1 would fix the API which VLC uses to solve the mixing sound problem at least but this doesn't appear to be the case

[larryy]

FWIW, this is not unique to Lion. I'm still running Snow Leopard (10.6.8, Build 10K549) on the next-most-recent 13" MacBook Air (immediately pre-Thunderbolt), connected via miniDisplayPort-to-HDMI to a brand new Samsung HT-D6750 home cinema system, and VLC 1.1.11 is messing up the channel assignment. Playing the same file with QuickTime Player the channels are properly assigned. So the problem is unquestionably in VLC itself.

[larryy]

One additional tidbit, that some might find useful... Though not a fix for VLC, it turns out that "MPlayer OSX Extended" with MPlayer's "Binary Codec Packages" installed is quite a decent alternative to VLC and QuickTime, that puts audio into the correct channels, and as a bonus will play some files that at least the current QuickTime + Perian codecs choke on. I discovered this when I encountered a couple of video files that crashed QuickTime Player 7, hung the modern QuickTime Player, and played with mixed up audio channels in VLC. MPlayer plays them just fine *and* puts the audio in the right channels.

MPlayer OS X Extended is available here: http://www.mplayerosx.ch/
The Binary Code Packages are available here: http://www.mplayerhq.hu/design7/dload.h ... ary_codecs

There's an article about MPlayer OS X Extended here: http://www.macstories.net/reviews/mplayer/

[pzich]

Any developments with this? It's a rather frustrating problem. Any way to make an audio filter or something similar that temporarily swaps the channels?

[Ltrainx]

I've been having the same sort of problem.

The centre channel was coming out the rear left and there was next to no signal coming out of my sub (where as normally it is quite overpowering).

All I did to rectify the problem was open Audio MIDI Setup (Applications > Utilities) and change the numbering of the speakers. They were initially numbered:

Front - 1
Center - 5
Right - 2
L Surr - 3
R Surr - 6
Sub - 4

But I changed them to:

Front - 1
Center - 2
Right - 3
L Surr - 5
R Surr - 6
Sub - 4

Which is the correct configuration for me. I hope this works for you!

http://i123.photobucket.com/albums/o287 ... 5739PM.jpg

[pzich]

I tried this and didn't see any change. What sound card are you using?

[xybazns]

I am experiencing a similar problem with 5.1 and 7.1 surround sound using VLC 1.1.12 on Mac OSX 10.7.2 running on a Mac Mini (Mid 2011, M816LL/A) hooked up to a Pioneer SC-1525-K receiver via HDMI.

I have gone through the Audio MIDI Setup tool in OSX and configured all the speakers so the channels come out of the correct speakers using the utility. Before I did this, I clicked the "Apply" button a few times with incorrect channel assignments before finally clicking on the "Apply" button with the correct channel assignments and verifying each speaker.

I then started up a fresh instance of VLC and loaded some files from http://www.demo-world.eu/trailers/high- ... ailers.php to test the setup. In particular the "Dolby TrueHD Channel Check (Lossless)" and the "DTS HD-Master Audio Sound Check 7.1 (Lossless)" files do not play correctly. VLC detects the files as 3F2R/LFE. That may be expected if VLC does not support 7.1 audio although I thought it was supposed to support Dolby TrueHD. Also, XBMC detects the DTS-HD MA file as 5.1 so most likely VLC is only detecting the core 5.1 stream like XBMC since there is no open source DTS-HD MA decoder out there yet.

When both of these files are played back, VLC plays the sounds out of the wrong speakers (mostly). For example, the Front Left channel comes out of the Left Rear Surround speaker, the Center channel comes out of the Left Side Surround speaker, the Front Right channel comes out of the Right Rear Surround speaker, and the Right Side Surround channel does not play back at all. XBMC is able to play the channels out of the correct speakers but it does not handle the Left/Right Rear Surround channels correctly (both the Side and Rear Surround channels come out of the appropriate Side Surround speakers only). I was testing VLC to see if it handled things any better when I noticed this issue.

I also played the THX -> Terminator 2 video (Dolby Digital 5.1) from the Demo-World site as well and it came out of the rear surround speakers instead of the front speakers. It is hard to say if the channel mapping is the same as the other files but it didn't sound right compared to playback using other apps that have the correct mapping.

Is this a VLC bug or can anyone suggest how to fix this without changing the channel assignment using the Audio MIDI Setup tool so that the sounds don't play out of the correct speakers but fix the mixed up mapping that VLC is using? I don't think it makes sense to change the mapping in Audio MIDI Setup just to fix VLC's incorrect mapping. It might mess up other apps that use the info as well that map the channels correctly.

BTW, I also tried running VLC 1.1.12 using Bootcamp in Windows 7 Home Premium. I configured the speakers in Win7 appropriately in the Control Panel sound settings and the same video files above played better than on OSX. Both the DTS-HD MA and the Dolby TrueHD 7.1 file had the side surround channels come out of the rear surround speakers instead of the side surround speakers. No speakers output sound while the rear surround channels were active. In order to get this far in VLC on Win7, I had to switch the output method to DirectX using AMD HDMI Output. Also, after playback of the video file started, I had to select the 5.1 audio device in the menu or else I only had the front speakers output sound. It looks like the OSX version of VLC 1.1.12 may be a little bit behind the Win7 version.

[saudor]

still doesnt seem to be working in lion 10.7.2. Im using Creative Sound Blaster X FI 5.1 USB. (SB1090)
It worked in OSX 10.6.8
Also works fine using Mplayer Extended (in OS X 10.7.2)