Regression: Bad Surround Channel Mapping on OSX with external audio cards

I just tried the latest build, my 5.1 surround channels are mapping to the wrong speakers in the release version of 2.1.2

v2.0.8 maps the surround channels perfectly

I run a MOTU 828mkII i/o

Changing routing parameters in Audio-MIDI Setup does not affect the way VLC 2.1.1 is arbitrarily routing 5.1 audio

the audio remapping feature in the VLC advanced settings has absolutely no effect either

I have used the same settings in Audio-MIDI Setup for many years My speaker routing/audio config is as follows:

https://dl.dropboxusercontent.com/u/10478471/Before%20Reboot%20AMS%20speaker%20routing.png

assigned to @fkuehne

added Component::Audio: macOS / iOS / tvOS / visionOS label

Hello,

Can we debug output for this issue? Open VLC, open the Messages panel, start playback, pause as soon as playback actually started, save the log. Feel free to post it here or on some paste bin.

Thanks!

For sure, here it is:

https://dl.dropboxusercontent.com/u/10478471/Garbagepump/VLC%20Debug%20Log%20%282.1.2%20Rincewind%29.rtf

Confirmed here, vlc seems to ignore the Audio Midi Setup channel mapping. (I'm routing the individual surround channels to a ADAT optical output).

You can try to reverse the stereo output in audio midi setup, this can be tested on any mac using the internal audio.

Ok, this is impossible to debug without a testing device. I'll try to get my hands on it.

changed title from Bad Surround Channel Mapping in 2.1.2 & 2.1.1 to Regression: Bad Surround Channel Mapping on OSX with external audio cards

added Severity::critical label

Unfortunately, I do not have a testing device. Would it be possible for you to test this build? If it is not working better, please upload a new log. https://www.dropbox.com/s/otemq85otkt88t8/VLC-channelmapping-test.zip

yes absolutely

send me anything you want me to test

I'll check this build later today

also if you devs have any diagnostic files you run through vlc that expedite the process, let me know

Any 5.1 test file is fine, for instance this one: http://download.tfm.ro/w32/test_ac3.rar

Replying to [comment:7 dfuhrmann]:

Unfortunately, I do not have a testing device. Would it be possible for you to test this build? If it is not working better, please upload a new log. https://www.dropbox.com/s/otemq85otkt88t8/VLC-channelmapping-test.zip

not sure what happened, downloaded it twice and attempted to unzip with 2 diff expanders....I think the zip might be broken

Sorry, my fault, the zip file I uploaded was corrupt.

I reuploaded a new zip (under the same link) which should work now.

Alright, whatever you did, has completely fixed my channel mapping problem

:)

Thanks for the feedback.

I see that you have even more free channels available. May I ask you to test two other things for me if its possible? That would be really great.

First, I am interested what happens if you do a 7.1 setup in Audio-Midi Setup and play a 5.1 source. (Maybe you can check the output of the 2 extra channels with a headphone?)

Second, I would be interested in a non-common setup where you leave the first channel in the list unused, and then assign your existing 5.1 setup to channels 2-7. Does the test file still play correctly?

It would be cool if you can test both scenarios with both my modified version of VLC, and the latest release version. Thanks for your support.

ya i can test 7.1 using meters

do you have a 7.1 test file?

No I haven't. If you find one, it would be interesting, too. But I am more interested what happens if you have a 7.1 setup, but only a 5.1 file.

ok I'll use the 5.1 test you gave me

I'm off for a run, if there's enough left of me when i get back I'll run the check tonight

For 7.1 streams http://streams.videolan.org/streams/channels/7.1/

assigned to @dfuhrmann and unassigned @fkuehne

commit c3bb23cd Author: David Fuhrmann david.fuhrmann@googlemail.com Date: Fri Feb 21 16:23:00 2014 +0100

auhal: rework channel mapping for analog surround output

The code reads the user-defined settings and adapts channel reordering accordingly,
not the other way around.

fixes [#10125](https://code.videolan.org/videolan/vlc/-/issues/10125), should also close [#10199](https://code.videolan.org/videolan/vlc/-/issues/10199)

Original author: david.fuhrmann@googlemail.com

added Status::fixed label

closed

Log from test run with VLC-channelmapping-test on Mavericks 10.9.2 , motu 828

Added attachment:

• VLC Debug Log (2.2.0-git Weatherwax).rtf

I tried the dropbox version of 2.2.0-git on my setup. It stills ignores my channel orderings (tried with AC3-test.rar Note in the log it says "no channel reordering needed".

Thanks for your report. Looks like you have the interesting case that you left channel 1 and 2 free. (BTW, is there any particular reason for that?)

Please complete your report by saying what signal you exactly hear from each of your channels. If possible, it is also helpful if you can check if you can hear something on your unused channels 1 and 2. A screenshot of your audio-midi setup channel mapping might be also useful.

I'll try a mapping with channels 1 and 2 used. Channel 1 and 2 are directed to the stereo input of my amp. (so the circuits for the surround output are not powered) Channel 3-8 to the discrete surround input of my amp. (It's even more complicated than that: I usually map the surround to the adat output which must be around channels 20-26 to a loop back into the sound interface which allows me to fine tune volume and eq of front and rear channels and redirect sub to the mains)

So you can't assume that input 1 and 2 (or even the first audio stream) will be used for output or that there would be no gap in the channels. You can't assume channels will be on the same stream (could be a composite audio interface). The same assumptions shouldn't be done for stereo either. (I might want to output stereo on the phones)

If you want to test this without an audio interface, I suggest you install soundflower which will act as a fake interface.

The mapping in use for the log: 5.1 surround. 3->left 4->right 5->left surround 6->left surround 7->center 8->sub (a screenshot would be of no use as the popup don't show the last characters) I tried the mapping: 1->left, 2->right, 5-> surround left, 6-> surround right, 7->center 8-> sub : doesn't remap I tried the mapping: 1->left, 2->right, 3-> center, 4-> sub, 5-> surround left, 6-> surround right : does remap I tried the mapping: 3->left, 4->right, 1-> surround left, 2-> surround right, 5-> center, 6-> sub: does remap (but strangely I had to restart VLC once more) I tried the mapping: 3->left, 4->right, 1-> surround left, 2-> surround right, 5-> center, 8-> sub: does remap but plays sub on channel 6 instead of 8

When remapping doesn't work the result is: 1-> left, 2->right, 3-> surround left, 4->surround right, 5-> center, 6-> sub

Note: 1-8 are channels named analog 1-8 on the interface which maps to 0-7 in the VLC log

1->left, 2->right, 3-> surround left, 4-> surround right, 5-> center, 8-> sub

Added attachment:

• VLC Debug Log (2.2.0-git Weatherwax) with gap to surround.rtf

Thanks for the detailed feedback. So basically, channel remapping works as long as you continously assign the channels from number 1 onwards.

Your setup is more complicated and has probably never worked with VLC. Thus, I created a new ticket #10800 (closed) as it does not really fit here anymore.

No: it worked great for years (I developed a patch a long time ago which was replaced by a much better design later). Last version working is VLC 2.09 even across streams.

This is really a (critical in my opinion) regression.

Do you have a link for your patch? I will check back with soundflower and 2.0.9.

No sorry, it was in 2004 and my patch was ugly and unfinished, you'd better check in 2.09 . So VLC does work in surround since 2004 or 2005 :)

But I read the current code, it can just reorder within the same number of channels. Some useful code must have been deleted.

The CoreAudio HAL unit (used for sound output) does channel reordering, and it should be optimized, so there is no need for VLC to reorder.

It could be that it's just misconfigured since 2.1.

Ah, sorry, you are absolutely right. 2.0.9 is working fine in your setup for me, too.

I compared the 2.0 and 2.1 implementation again and it looks like I found the small one-liner bug. At least, your setup seems to work fine now with Soundflower.

Here is a new build so you can check again: https://www.dropbox.com/s/whileufn8452chm/VLC-channelmapping-test-2.zip

Please report back if its working for you now.

Works great for me, Thanks a lot!

commit a748266b Author: David Fuhrmann david.fuhrmann@googlemail.com Date: Thu Feb 27 22:12:34 2014 +0100

auhal: correctly fix channel ordering by setting the correct scope.

fixes [#10125](https://code.videolan.org/videolan/vlc/-/issues/10125), [#10199](https://code.videolan.org/videolan/vlc/-/issues/10199)

Original author: david.fuhrmann@googlemail.com

mentioned in issue #10800 (closed)