My Libreelec is not capable of Dolby Digital Plus DD+ passthrough on Raspberry!

  • Around 10 diffrent DD+ samples I tested from my library play well on RPi2 and RPi4 from 5.1 up to DD+ 7.1 with Atmos, where my Denon AVR says Dolby Atmos. Tested with 9.2 latest git version.

    That is really great.

  • Here is a log of DD+ successfully passthrough-ing for me.

    Code
    https://pastebin.com/uRrRTAYW

    Understanding exactly what is happening in the logs is above my abilities but to me it seems like your Pi is sending out DD+ in exactly the same way as mine. Perhaps your receiver is at fault? Is there an update for it?

  • Hi trent and Da Flex, you have to remember that I have the exact klone of Kodi running under Windows and there it works fine.

    Have tried the default skin anyway, same result.

    I also have tried to switch HDMI cables and conectors at the AVR, all without success.

    It is somewhere in the LE / RasPi. But officials here a not keen on investigate that.

  • Code
    ############################
    LibreELEC (official): 9.0.2 (RPi2.arm)
    KODI-TV:~ # cat /storage/.kodi/userdata/guisettings.xml | grep passthrough
        <setting id="audiooutput.ac3passthrough" default="true">true</setting>
        <setting id="audiooutput.dtshdpassthrough" default="true">false</setting>
        <setting id="audiooutput.dtspassthrough">true</setting>
        <setting id="audiooutput.eac3passthrough" default="true">false</setting>
        <setting id="audiooutput.passthrough">true</setting>
        <setting id="audiooutput.passthroughdevice">PI:HDMI</setting>
        <setting id="audiooutput.truehdpassthrough" default="true">false</setting>


    No additional audio hardware. Model is Raspi 3 B+

  • Sorry Da Flex that makes no sense. First of all it would setup audio output to Stereo. But even if I chose 5.1, if I deactivate passthrough, audio is send as PCM and the Receiver doesn't recognize the format anymore -> shows Multi Channel In.

    And also the RPi is not the audio source, the source is the audio stream itself and the question is whether Kodi should decode it and send it as PCM to the receiver or should it be passed to the AVR as it is and let the receiver do the job of decoding. Later is the option I want of course.

  • I think Da Flex is talking about getting the Raspberry Pi to decode DD+ to PCM in the Pi, whereas Novalis wants passthrough/bitstreaming, where the DD+ bitstream is passed, untouched, from the Pi to the AVR for the AVR to decode?

    Both are valid approaches for non-Atmos content, and the 'decode to PCM' is the only approach for the Pi 3B+ and below for Dolby True HD and DTS HD MA (which the Pi traditionally can't bitstream *), whereas the Pi can bitstream/passthrough DD and DTS. It seems some have reported success with DD+ bitstream/passthrough.

    (*) The Pi 4B supports 8 channel 192kHz over HDMI which means it should allow HD Audio passthrough (the previous generation of Pis only had enough bandwidth for 4 channel 192kHz so couldn't)

  • Code
    <setting id="audiooutput.eac3passthrough" default="true">false</setting>

    I have no knowledge about possible hardware/software limitations of the RPI but EAC3/DD+ passthrough is disabled in your configuration.

  • How can I break up a citation?

    Edited once, last by novalis (June 30, 2019 at 9:51 AM).

  • Code
    <setting id="audiooutput.eac3passthrough" default="true">false</setting>

    I have no knowledge about possible hardware/software limitations of the RPI but EAC3/DD+ passthrough is disabled in your configuration.

    Yes, very sharp. The reason is to be found in the title of this topic.

    This is the center of the problem.

    Enable it - nothing.

    Disable it - PCM

    Edited 2 times, last by novalis (June 30, 2019 at 9:56 AM).