No HDMI Audio

  • Hi

    I'm using LibreELEC-RPi4.arm-9.1.002 on a Raspberry Pi 4 with a Toshiba TV and can't get HDMI sound to work.

    Any combinations of the following _do not_ work:

    - Two different HDMI cables (micro HDMI to HDMI)

    - With passthrough and without

    - Youtube or BBC iPlayer add ons

    The following setups _do_ work:

    1. Toshiba TV + normal HDMI Cable + playing youtube from my laptop

    2. Alba TV + micro HDMI Cable + playing youtube from the Raspberry Pi 4

    And what I want is this, which currently does not work:

    3. Toshiba TV + micro HDMI Cable + playing youtube (or anything) from the Raspberry Pi 4

    Set up 3 doesn't work whatever order I start the devices up in (TV first vs. Pi first) but what really strange is if I start up in set up 2, with the Alba TV, then move the HDMI cable to the Toshiba TV to get set up 3 the sound does continue to work!

    Log files are here:

    Set up 2, with the Alba TV. Does work: http://ix.io/1upd

    Set up 3, with the Toshiba TV. Does not work: see log file http://ix.io/1upc

    I'm assuming LibreElec or Kodi are not detecting something correctly with the Toshiba TV but I'm a bit lost seeing what it is from the logs. Can I manually set the correct HDMI sound settings for the Toshiba TV? Any help would be greatly appreciated!

    Thanks

    Adam

  • Available options for Audio output device are:

    PI: HDMI

    PI: Analogue

    PI: HDMI and Analogue

    PULSE: Default, Bluetooth Audio (PULSEAUDIO)

    I tried both with HDMI and with various numbers of channels like 2, 2.1, 3, 4... but no combinations work when I boot up connected to the Toshiba TV.

    However, if I boot up connected to the other TV then switch the HDMI cable over to the Toshiba it works fine with:

    Audio output device: PI: HDMI

    Number of channels: 2

    Allow passthrough: yes or no (works both ways)

    It seems to me the issue is not with the System Settings / Audio but some kind of config or detection of the HDMI audio capabilities at boot up time. What do you think?

    Edited once, last by agriffiths (September 6, 2019 at 9:20 PM).

  • I solved it with hdmi_drive=2

    For anyone else who comes across this issue here's how to make the setting change. You need to have ssh enabled, then from another computer ssh to the libreelec box (replace ”libreelec” with the name of your box):

    ssh root@libreelec


    Then:

    mount -o remount,rw /flash

    nano /flash/config.txt


    And add the line:

    hdmi_drive=2


    Ctrl+o to save and Ctrl+x to exit nano. Reboot and it should all work. You should also consider adding the line:

    hdmi_force_hotplug=1


    Which will ensure HDMI is used even if unplugged or the TV is off when the libreelec box is turned on.