Incorrect audio channel configuration/mapping on multichannel audio to HDMI (without pass-through)

p__g · September 7, 2023 at 3:27 PM

I've installed (fresh installation) LibreELEC 11.0.3 on an AMLogic S905 TV-Box (p201) and also on Raspberry PI 4.

Because my Amp does not support newer audio formats I can not pass-through them.

I've set in the audio settings that I have 5.1 channels.

When Kodi decodes 5.1 or 7.1 audio data and outputs them as PCM to HDMI the channel mapping is wrong.

On the S905 box, the output to the amp is as I would have set 4.0 or 4.1 channels; the center is sent to FL and FR.

On the PI 4, the output is as would have set 3.1 chennels; RL goes to FL and RR to FR.

I tried the different audio devices from the menu and also with 'fixed' setting or 7.1. It's always as written above.

This is not an issue with the amp connected to LE/Kodi or the files I play. I have an old PI 1 with LE 9.2 and there all the audio signals are sent to the correct speaker.

What is the problem and how can it be fixed?

PS: AAC Test file is from here: https://www2.iis.fraunhofer.de/AAC/multichannel.html

and the E-AC-3 file from https://www.reddit.com/r/htpc/comment…t_every_format/

**HiassofT** · September 7, 2023 at 6:56 PM

Did it work fine with 11.0.1?

If yes then quite certainly the reason is I messed up (chewitt reported it to me earlier this week). A fix for that should be out soon (just need to find some spare time).

so long,

Hias

**HiassofT** · September 7, 2023 at 9:18 PM

Can you please test with this LE11 RPi4 build and report back if multichannel PCM works again?

https://www.horus.com/~hias/tmp/libreelec/LibreELEC-RPi4.arm-11.0-devel-20230907220746-677274a.tar

so long,

Hias

p__g · September 8, 2023 at 10:24 AM

Good news! The test build above fixes the problem. (I've only tested with 5.1 output)

I would be happy to see an official release for PI4 and AMlogic as well.

I guess a lot of users of 11.0.3 are affected from this bug.

**HiassofT** · September 8, 2023 at 10:58 AM

Thanks a lot for reporting back, the fix for RPi, Allwinner, Rockchip etc has already been added to LE11 and LE12 https://github.com/LibreELEC/LibreELEC.tv/pull/8123 and will be in the next nightly builds (and also in further releases): https://test.libreelec.tv/

Amlogic is a different thing though, the LE kernels didn't include the offending change (but other changes that might affect multichannel PCM), I'll leave that to chewitt

so long,

Hias

p__g · September 9, 2023 at 3:20 PM

I did a test with 11.0.1 instead of 11.0.3 on the S905 box and with 11.0.1 the channel mapping is correct.

dasacco · September 14, 2023 at 3:29 AM

I'm pretty sure the problem I reported on August 16 is the same as the one in this thread. Am I correct?

Aug 16th 2023

#1

Running 11.0.1 I was able to play multichannel FLAC files on my Raspberry Pi 4 over HDMI to my Audio Video Receiver.

After upgrading to 11.0.3 only the front channels would play. My receiver was showing all five channels coming in, but apparently some kind of downmixing to the front channels is occuring.

I reinstalled 11.0.1 and everything is working fine now.

And it also appears from this thread that it has been addressed. Please forgive the newbie question, but do I wait for 11.0.4 or if I reinstall 11.0.3 will it now work?

Many thanks!

Dave

**HiassofT** · September 14, 2023 at 11:31 AM

You can either use 11.0.1 and wait for 11.0.4 (no ETA on it though yet) or install the latest LE11 test build from here: https://test.libreelec.tv/11.0/RPi/RPi4/

The official 11.0.3 version has not been changed.

so long,

Hias

dasacco · September 27, 2023 at 6:58 PM

Quote from HiassofT

You can either use 11.0.1 and wait for 11.0.4 (no ETA on it though yet) or install the latest LE11 test build from here: https://test.libreelec.tv/11.0/RPi/RPi4/
The official 11.0.3 version has not been changed.
so long,
Hias

Thank you!