Audio is sent to wrong channels

[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!

[outofyourhead]

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

I found a copy of VLC 2.2.0 here:
http://www.libde265.org/static-download ... .0-git.dmg

I installed it and the channel mappings are still wrong and unchanged from all previous versions.

However, even worse, two of the channels, I think channel 5 and 7 do not work at all. There is no audio output on those channels. Since channel 5 is wrongly mapped as the center channel, you can't get the center channel audio in version 2.2.0.

Oh well...

[dfuhrmann]

Please wait until our nightly builds server is back online.

If it still does not work, you need to give exact details about your speaker configuration and about the source format.

[outofyourhead]

Please wait until our nightly builds server is back online.

If it still does not work, you need to give exact details about your speaker configuration and about the source format.

I just tried the latest nightly build dated 5/04.

Unfortunately it still has problems with the 5.1 or 7.1 channels mapping.

The source format I am using is an MKV file ripped from a Blu-Ray with 7.1 audio. To test the movie, I tried playing it in XBMC in OS X and in VLC and JRiver Media Center on Windows. In all the other apps, the channels play from the correct channels.

But on VLC on OS X, I do not get a center channel at all.

I think the channel mapping is still the same as previous versions:

1 Left (no change)
2 Right (no change)
3 Right Surround (Should be Center)
4 LFE Screen (no change)
5 Rear Surround Left (should be Left Surround)
6 Rear Surround Right (should be Right Surround)
7 Center (should be Rear Surround Left) - This channel is not playing at all. It was playing in the release version of VLC.
8 Left Surround (should be Rear Surround Right) - This channel is also not playing at all. It was playing in the release version of VLC

I am using my software "Out Of Your Head" to listen to the output of VLC. My software appears as a 7.1 virtual sound card and then outputs the sound of 8 separate speakers in headphones. Actually it shows up as a 16 channel audio output device in OS X.

I am pretty sure it's not my software that's an issue since I can playback content in XBMC and Quicktime and the channels are mapped correctly.

Let me know if you need more info, but I think this is the same bug that has been present from the beginning of the OS X version of VLC.

I think if you just change the channel mapping internally in the VLC code, that's all that it will take.

Thanks for your help.

[dfuhrmann]

Thanks for your report.

You are only describing a problem with 7.1 surround, so 5.1 works fine? I would be glad if you can file a bug report on https://trac.videolan.org/vlc/. Just copy-pasting the important parts of above post should do. Additionally, It will be helpful if you upload a VLC log and state your OS version.

Internally, VLC already reorders channels for all kind of speaker configurations, including 7.1. But as most of us do not own a 7.1 device, it quite hard to test.

[vanuan]

HDMI supports 8ch LPCM audio. VLC sends only 6channels. So the issue is that when "HDMI" audio output option is chosen, VLC should output 8ch PCM audio even if the source file only contains 6 channels. It outputs only 6channels, so as a result we hear central channel at the right surround position.

As a workaround we can choose "passthrough" mode which is called "HDMI (encoded output)" in VLC.

[vanuan]

Here are some results when playing DTS encoded file.

Here's what Denon sees when HDMI is chosen (notice PCM signal):


Here's what Denon sees when HDMI (encoded output) is chosen (notice DTS as signal):

[vanuan]

If in doubt whether you're listening to passthrough or reencoded signal, try increasing volume in VLC. If you hear volume increasing you're in the reencoded mode. If VLC volume slider doesn't affect what you hear, you're in passthrough mode.

[Ciarzo]

Newly released files in MKV having been torturing me with this problem for the last week or two. Specifically True Detective, everything I have that’s historic works fine.
Any suggestions or is this another update?

My AMP shows PCM file also. Unsure if it’s DTS or Dolby I’m reality though

[TheBucketOfTruth]

This post is from 2012 how is this still an issue when we're almost in 2022? I swear I had found a solution for this once before but am back again with the same issue. Maybe it was fiddling with the audio device before? Running a five channel what's listed as a eac3 audio file paired with a H265 .mkv video file. Is there an issue with the codec and VLC? My receiver? I'm on Mac OS Catalina 10.15.7 and the latest VLC (updating didn't help). 15 inch MacBook Pro from 2018 running HDMI from my thunderbolt port. I have an Integra DTR-70.4 older receiver. 5.2 system and having that same issue where the dialogue is all being sent to the surround left speaker. Just screwed around googling and messing with all sorts of settings but nothing made a bit of difference. Did anyone find a permanent fix? Is this codec not compatible with VLC?

PS: Oddly enough I tested the same files on an old Late 2014 Mac mini running 10.13.6 and VLC 3.0.12 and it works just fine.

[bluething]

Hi. I have the same problem when playing .mkv and using my Denon AVC-X6500 and using the latest VLC 3.016 Apple Silicon on MacMini M1 2020, macOS Monterey. The speech from center channel is coming from left surround speaker.
Please help.