Audio is sent to wrong channels

[stokestack]

Hi all.

I have my MacBook Pro sending audio to a Denon receiver over HDMI. When I play MKVs, the audio is directed to incorrect channels. It appears that the center channel is directed to the left surround channel, and other audio is spread across the three front channels. I don't hear anything from the right surround channel.

As the audio-signal description, the receiver shows "multi channel in", which is quite non-specific. If I change VLC's audio device from HDMI to "HDMI (encoded output)", the receiver shows Dolby Digital.

What is VLC sending when normal HDMI is selected as the output device, and why is the channel distribution so bizarre?

Thanks for any insight.

[fkuehne]

VLC is sending "analog" multi-channel audio if the encoded output isn't used. How many channels does your audio and your setup have? 6.1 or even 7.1?

[Shugashuck]

Hi Guys,

I'm actually having the same problem, but with a different setup.
I have a mid-2010 Mac Mini, which is connected to my LG 2.1 reciever through a HDMI cable.

When I play a mkv-file, which normally has DTS encoded sound, the speech are directed to my left speaker. Music and background sound are coming from both speaker, though, with a slight more to the left speaker.
This happens when I have the sound output within VLC player to "HDMI", when I change it to "HDMI Coded" it will be corrected, though, I will now longer have the real power in the speaker, and the sub are almost inactive.

I noticed this with the VLC v. 2.0.1, and efter I upgraded OSX to version 10.8.0. I have in a manner of troubleshooting, downgraded to 2.0 without any impovement. I have also tried both 2.0.3 (stable) and the pre-release - 2.0.4, none which correting the problem.
Prior upgrading to OSX 10.8.0 the sound worked fine with the same HDW setup, and the sound output set to HDMI.

I have also tried Movist and MplayerX but these does not show the sound problem (but in these cases the picture quality in not as good as the VLC), therefor I'm very anxious to have VLC player working again

It feels like the problem (at least for me) where introduced when I went from OSX Lion to Mountin Lion.

Would be great if you perhaps have some clues what have caused this change, clues etc.

Thanks in advance!

/Chris

[bushd]

I just bought a new mac mini and I have the same problem. I connected my mini via hdmi to my reciever and the sound is all wrong, but only with vlc.

Please is there a fix or are you working on one?

[olouvignes]

It appears that the center channel is directed to the left surround channel, and other audio is spread across the three front channels. I don't hear anything from the right surround channel.

I do have the exact same issue on OSX 10.8.2 on a MBP with HDMI output on a DENON amp.

Setup is 7.1 channels (did configure them correctly & in "audio & midi configuration", the mapping correctly works there with the test sounds). Is there a ticket for this bug?

[Jean-Baptiste Kempf]

I don't think there is.

[fkuehne]

Hello,

we think that we isolated the cause for your issues. We will have a test setup at hand this december and provide a fix in the version following our meeting.

I just created ticket 7783 for you to track.

Thanks for the reports!

[RobotTwo]

I'm having the same problem, with a 7.1 output sent via HDMI to a receiver with 9.1 output (7.1, plus upper right and upper left channels). The problem doesn't happen with MPlayer or Quicktime.

A fix would be much appreciated!

[fkuehne]

We purchased a 7.1 setup thanks to the voluntary donations to the VideoLAN association, so we can test our fix right away during our audio output hacking session this December.

Stay tuned!

[ez-1]

I've had this same problem for a few years now and it's still there after the lates OS update. Any news about this issue? I would like to volunteer as a tester if you don't have "working" environment to test this.

My setup is as follows:
Denon 3311 amp
Mac Mini Mid 2010
HDMI between Mac and amp and HDMI from amp to TV

Audio MIDI setup is set to 48kHz 8ch-24bit Integer
and at the Configure Speakers everything works and sounds come from correct speakers. I've tried with VLC and hd_dolby_truehd_channel_check_lossless.m2ts and it only plays few channels right rest are either mute or coming from wrong speakers.
Speaker setup is 7.1 Rear Surround and Audio setup from VLC is HDMI (Encoded Output)

Thanks

[fkuehne]

Hey,

can you check whether this is still an issue with version 2.1.0 available from www.videolan.org?

Thanks!

[ez-1]

Alrght!!!! That's awesome. I opened VLC today and it said there is an update but for some reason it only updated it to 2.0.9. Went to videoland.org and downloaded the latest version and now it works. There is new devices in the Aduio Device lists and I left it on System Sound Output Device. Also HDMI (Encoded Output) seems to work.
Now where can I donate?

[fkuehne]

Great to hear that it works for you! 2.0.9 is an intermediate release needed for some older Macs. 2.1 will be pushed through the updater in a few days!

For donations: check the link on the top right on videolan.org or email us at videolan at- videolan dot org - thanks so much!

[ez-1]

Done

[RobotTwo]

I updated to 2.1, and it's still a problem for me. The center channel seems to be sent to the rear-left speaker. I connect my mac mini to a 9.1 receiver via HDMI. The problem only happens via VLC, not when I use other media players.

[Jean-Baptiste Kempf]

you should file a bugreport.

[caio80]

Happening to me to right now. Just filed https://trac.videolan.org/vlc/ticket/10199 for this.

Everybody with this issue, please follow up there with MEANINGFUL details, and NOT here.

Thanks all for this wonderful software!!!

[caio80]

BTW, the best thing you could do is:

1) Go to the bug
2) Get the test file https://trac.videolan.org/vlc/ticket/10199
3) Test on your setup and detail what you hear and from which speakers.
4) Report similarly to what I did (first bug comment), WITHIN the bug page, not here.

[caio80]

For the moment, unfortunately the workaround is to switch player. Mplayer X had a similar issue but with different wrong channels... I fixed it though by setting Force detection of SPDIF, then setting passthrough of DTS/AC3, and having my Mac audio options defaulting to output through HDMI.

[marklnp]

I think everyone is kinda barking up the wrong tree with this. I've run some tests, and I've concluded: it's not a Mac thing, it's not an encoding thing. It's VLC either misreading a channel identifier in the audio stream/file header, or making an erroneous assumption about the how the channel assignments should be. In any case, I can show it's VLC that's the problem. To wit:

I'm playing the stock Microsoft test identifier 5.1 surround WAV ("Front Left, Front Right, Center..." you've heard the guy; it's here: http://download.microsoft.com/download/ ... hannel.exe). 48kHz, 6 mono channels in a WAV wrapper. No encoding, straight PCM wave audio. Channels are assigned according to the "Zero-based order within multi-channel datastream" (see http://en.wikipedia.org/wiki/Surround_s ... o_speakers) i.e, L, R, C, LFE, Ls, Rs.

VLC 2.1.1 plays this WAV correctly. Audio comes out the correct channels. So it is possible for VLC to do it.

Take that same 6-channel WAV, play it with QuickTime (I have Pro). QT Player also plays the WAV correctly. Check the Movie Properties in QuickTime Pro, the Audio Settings tab. Channels appear in the same order.

In QuickTime, save the WAV as a MOV. Play the MOV in QuickTime. It plays correctly. Channels still appear in the same order.

Play the MOV in VLC -- and it screws up the order of the channels as people have been complaining about for years.

If you look at that table in the Wikipedia article, you see that under the DTS/AAC spec, the Left Surround channel has an ID of 3. Sure enough, that's the third channel down, the center channel in the other numbering scheme. The Right Surround under DTS/AAC is ID'ed 4 -- which is the fourth channel down, the LFE channel in the other scheme.

Notice how everyone's been bitching about how their center channel audio comes out the Left Surround, and there's virtually no Right Surround? Q.E.D.

I predict that VLC is (and has been for years) making an assumption that any QuickTime MOV it plays must be using the DTS/AAC channel assignment scheme, and it applies their weird channel mapping for it, regardless of whether that may truly be the case or not.

We can rule out a Mac/PC thing. I have VLC 2.1.1 installed on both a Mac and a PC. It functions the same way on both platforms. VLC *can* play a surround WAV with channels assigned correctly. But It mis-assigns the channels when that same WAV is inside a QT MOV, when QuickTime plays it properly.

it's not an encoding thing; no DTS/AAC, AC3, SPDIF, HDMI, none of that is involved. All the other issues mentioned in this thread and others are probably false leads. It's VLC that's simply assigning channels wrong, at least with QuickTime MOVs. It's probably the same error occurring with the encoded formats too, so having the end-user trying various encoding settings and OS versions to fix an inherent problem higher up in the program code is certainly an exercise in futility.

I wish I knew how to fix it -- but I'm not a coder. It's up to the programmer team to suss out what they're doing -- and come up with a way to stop doing it!

Team -- what say you?

>> Mark

[chmedly]

I'm finding the channels are wrong with mac version 2.1.4. I can play the same file in quicktime and it's correct, in VLC the center channel actually appears in the front left channel. My memory likely fails me but I thought there was a channel assignment matrix in VLC in previous versions. "correcting" the assignment in audio/midi settings will just mess it up for other playback software.

[dfuhrmann]

Try the latest 2.2 nightly build, it should be fixed here.

[larryy]

Actually, the problem is with the Mac. I've hit this problem before, and resolved it, but couldn't remember exactly how. But when the absolute latest VLC 2.1.4 sent audio to the wrong channels on my new MacPro, I went digging again. First I found this and some other threads on videolan.org, but I don't think the problem has been diagnosed correctly. Fortunately, I also found the solution. I don't know why Macs ship this way or why some software still seems to work, but the problem is in the Mac's audio setup, and once you know how, it is quite easy to fix. See the instructions in the top post here: http://forums.macrumors.com/showthread.php?t=1314744. Particularly the "Instructions" section. In fact, in case that ever goes away, here are the most salient bits excerpted:

INSTRUCTIONS
The key to getting dialog to play (indeed, all channels of the source file to play via the correct speakers in your surround system) correctly, i.e., as it was meant to be heard, is to configure the speaker map on your Mac properly. Follow these instructions, as tested on Mac OS X 10.7.2 (earlier versions may be slightly different):
1. You need to enable AC3/DTS passthrough. Go to Applications>Utilities>Terminal. When the application opens, copy and paste the following, without the quotes, then press enter: “defaults write com.cod3r.a52codec attemptPassthrough 1” and “defaults write org.perian.Perian attemptDTSPassthrough 1”. q.v. FOOTNOTE 1
2. Connect the HDMI cable from your AVR to your Mac. Make sure you select the proper mode on your AVR so your computer is recognized. Make sure your audio output device in OS X is changed to, e.g., "DENON-AVAMP" (other AVRs will show something else) from the default "Internal Speakers", otherwise, your audio will play through your internal computer speakers. You can quickly switch the audio output device by clicking on the sound icon in the top menu bar, whilst holding option on the keyboard. If you don't see the sound/volume icon in your menu bar, go to the apple icon in the top left, click System Preferences>Sound. Then click the box for "Show volume in menu bar". This will make your life easier.
3. Go to Applications>Utilities>Audio MIDI Setup
4. On the left side of the "Audio Devices" window that appears, click "HDMI".
5. Change Format to 48000.0 Hz and in the dropdown to the right, select “8ch-24bit Integer”. q.v. FOOTNOTE 2
6. Now click “Configure Speakers”. In the top right, select the surround system you have. I have 5 speakers (no subwoofer), but I selected “5.1 Surround”. Click each speaker name to make sure sound comes out of the speaker name you just clicked. Adjust as necessary.

Perhaps because I had set all this up on an older Mac from which I imported my settings (using Migration Assistant), all but the last step (6) were already in place on my system. (Note, you can see the state of the defaults you are told to change in step 1 by typing "defaults read com.cod3r.a52codec attemptPassthrough” and “defaults read org.perian.Perian attemptDTSPassthrough” if you want to check them before you change them.) Once I selected "Multichannel" and "5.1 Surround" in step 6, all was well, and VLC works as intended.

Keep up the great work, VLC contributors, and don't waste time on this non-bug.

[RobotTwo]

That's not the problem. I see this too on a 9.1 system. If I follow the instructions from larryy, the Mac plays all the output through the correct speakers, as does Quicktime, but VLC does not.

[outofyourhead]

Try the latest 2.2 nightly build, it should be fixed here.

Where do we download the latest nightly builds? http://nightlies.videolan.org/build/macosx-intel/ is not working.

Thanks!