HD Audio from DisplayPort - no sound (HDMI works)

  • Related thread: Force display output to DP with audio on HDMI where I am trying to use the HDMI for sound and DP for video.

    I wanted to dig deeper into why the DP 1.2 on my Optiplex 3050 is not able to play HD audio. I've made some progress (I think!) but I'm stuck on where to go from here. If it is a limitation of the DP itself, I'd like to understand why.

    Here's my findings:

    HD Audio (TrueHD and DTS HD MA) from HDMI 1.4 works - log here:


    HD Audio (TrueHD and DTS HD MA) from DP 1.2 DOES NOT work - log here:


    In both cases, it first tries to create a 2 channel output stream:

    Sample Rate : 44100
    Sample Format : AE_FMT_S32NE
    Channel Count : 2
    Channel Layout: FL, FR

    and then an 8 channel output stream:

    Sample Rate : 192000
    Sample Format : AE_FMT_S16NE
    Channel Count : 8
    Channel Layout: RAW, RAW, RAW, RAW, RAW, RAW, RAW, RAW

    I suspected perhaps the DP 1.2 does not support 192000khz with 8 channels, but if I run a speaker-test command, it works fine:


    If I turn off passthrough in Kodi settings, LPCM 7.1 is sent fine via the DP for all 8 channel HD audio streams.

    Any guidance on what I can check next?

  • Double post. Continue here:

    fezster
    January 15, 2024 at 12:58 PM