5.1 sound doesn't work on RPi4

    Hi,

    5.1 sound doesn't work on Raspberry Pi 4 2GB using LibreELEC 10.0.3. There are recognized FL and FR channels only.

    I've tested two different setups, different TVs, different RPi4s, clean installations, always the same.

    lspci

    Code
    00:00.0 PCI bridge: Broadcom Inc. and subsidiaries Device 2711 (rev 10)
01:00.0 USB controller: VIA Technologies, Inc. VL805 USB 3.0 Host Controller (rev 01)

    lsusb

    Code
    Bus 002 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub
Bus 001 Device 003: ID 248a:168e Maxxter KbMouse
Bus 001 Device 002: ID 2109:3431 VIA Labs, Inc. Hub
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub

    dmesg

    Hastebin: Send and Save Text or Code Snippets for Free | Toptal®

    Edited once, last by waclaw66 (November 30, 2022 at 7:04 AM).

    Please provide a full debug log.

    How to post a log (wiki)

    1. Enable debugging in Settings>System Settings>Logging
    2. Restart Kodi
    3. Replicate the problem
    4. Generate a log URL (do not post/upload logs to the forum)

    use "Settings > LibreELEC > System > Paste system logs" or run "pastekodi" over SSH, then post the URL link

    TVs usually don't support 5.1ch PCM - if you connected the RPi to an AVR that'll be different.

    If your TV accepts AC3/DTS/... and can decode it or pass it through to an optical output, (E)ARC HDMI port etc then enable passthrough support in audio settings, choose the HDMI device and select available formats (AC3 etc - you need to be in expert level mode to see them)

    so long,

    Hias

    Quote from HiassofT

    TVs usually don't support 5.1ch PCM - if you connected the RPi to an AVR that'll be different.

    If your TV accepts AC3/DTS/... and can decode it or pass it through to an optical output, (E)ARC HDMI port etc then enable passthrough support in audio settings, choose the HDMI device and select available formats (AC3 etc - you need to be in expert level mode to see them)

    so long,

    Hias

    My Samsung TV supports PCM or bitstream at input same as in this arcicle...

    PCM vs Bitstream For Samsung TV - Planet HiFi
    PCM vs Bitstream For Samsung TV Table Of Contents Hide PCM vs Bitstream For Samsung TV PCM vs Bitstream When Connecting External Devices Through HDMI Digital…
    planethifi.com

    I've tested both settings, but LibreELEC shows only 2 channels supported in the log.

    My setup is LibreELEC ==HDMI==> SamsungTV ==SPDIF==> DECODER ==line cables==> 5.1 speakers

    The article you linked to says:

    Quote

    PCM: This stands for “pulse-code modulation.” Use this setting if the external device you have connected to the HDMI port has already processed the sound, and you just want it to come out of your TV’s speakers.

    This setting configuration for the Samsung TV changes the signal to 2.0 PCM as it passes through the TV. If you select PCM even though you have a home theater system or soundbar connected, the sound system will only receive 2.0 channel sound and the result will not be multi-channel surround sound, even if the sound system is capable of multi-channel PCM audio.

    So that setting is 2 channel PCM only.

    Also you are using SPDIF, which can handle stereo PCM, or compressed 5.1 using AC3 or DTS. It won't support multichannel PCM.

    In kodi, set channels to 2.0. Enable AC3 passthrough. Enable AC3 transcode. You will get multichannel output from your 5.1 speakers (it will be using AC3 as the actual format that goes over SPDIF).

    Quote from popcornmix

    The article you linked to says:

    So that setting is 2 channel PCM only.

    Also you are using SPDIF, which can handle stereo PCM, or compressed 5.1 using AC3 or DTS. It won't support multichannel PCM.

    In kodi, set channels to 2.0. Enable AC3 passthrough. Enable AC3 transcode. You will get multichannel output from your 5.1 speakers (it will be using AC3 as the actual format that goes over SPDIF).

    You're a genius 👍 It works! Thank you very much.