Posts by frank78

  • [RPi4] No HDMI Audio Passthrough in LibreELEC 12.0.2

    🔹 System Details:

    • Device: Raspberry Pi 4
    • AV Receiver: Denon AVR (connected to HDMI0)
    • LibreELEC Version: 12.0.2
    • Kodi Version: 21 (Omega)
    • Audio Output: HDMI (ALSA)

    After a fresh install of LibreELEC 12.0.2 onto a new SD Card, audio passthrough no longer works.
    My old LibreELEC 11 had no problems serving audio passthrough.
    Now, Kodi only outputs PCM, even though the AVR supports Dolby Digital, DTS, TrueHD, etc.

    I've had a little troubleshooting with ChatGPT and this is how we've got so far...

    🔎 Key Findings

    1️⃣ HDMI audio was initially disabled in the kernel:

    Code
    dmesg | grep -i hdmi

    showed this boot command:

    Code
    snd_bcm2835.enable_hdmi=0

    → HDMI audio was disabled by default.
    → Changed to snd_bcm2835.enable_hdmi=1 in cmdline.txt, but this had no effect after reboot.

    2️⃣ ALSA now recognizes HDMI audio, but passthrough is still unavailable in Kodi:

    Code
    cat /proc/asound/card0/pcm0p/sub0/hw_params

    now returns:

    Code
    access: MMAP_INTERLEAVED
format: IEC958_SUBFRAME_LE
subformat: STD
channels: 2
rate: 48000 (48000/1)
period_size: 2400
buffer_size: 9600

    → So ALSA is working, and the HDMI output is active.
    → But Kodi does not offer passthrough in settings.

    3️⃣ Kodi still detects Pulseaudio, even though ALSA is active:

    Code
    cat ~/.kodi/temp/kodi.log | grep -i audio
    Code
    warning <general>: Pulseaudio module module-allow-passthrough not loaded - opening PT devices might fail
info <general>:         m_displayNameExtra: Bluetooth Audio (PULSEAUDIO)

    → Pulseaudio is running, but should not be used for HDMI.
    → Disabling Pulseaudio (systemctl stop pulseaudio) had no effect on passthrough.

    🆘 Questions for the Forum

    ❓ Why is passthrough unavailable in Kodi, even though ALSA now recognizes HDMI?
    ❓ Is there a known issue in LibreELEC 12.0.2 that prevents passthrough from working?
    ❓ Does LibreELEC 12 use a different approach for HDMI audio handling (e.g., changes in vc4-hdmi)?
    ❓ Any additional logs or tests I should run to troubleshoot this?

    Any help or insights would be greatly appreciated! 🎧🔥