PCM Multichannel stuck at 32khz?

  • Hi all,

    Hardware: MINUX U9-H

    LibreELEC: adamg's LibreELEC 9.0 Alpha for Amlogic S905/S912 devices, version 8.90.3 (same behavior also in kszaq's LibreELEC 8.2 for S912, version 8.2.2.3)

    Receiver: Yamaha RX-V681

    I'm having some trouble with multichannel PCM output from Kodi to my Yamaha receiver. I have a 7.1 system, and Kodi audio is set to 7.1 with "Best Match". When I try to play any multichannel movie with an audio track that can't be bitstreamed (FLAC or Opus), my receiver gets 8 channels of PCM at only 32khz. I'm concerned that I'm losing significant fidelity due to this issue.

    Kodi's CodecInfo showing 48khz: http://imgur.com/hBp9NWI

    Yamaha Receiver showing 32khz: http://imgur.com/jZ8dFNP

    I'm attaching a full debug log from playing a video with 5.1 Opus audio, but here is an excerpt showing that the audio stream created is 48khz:

    Code
    02:41:52.909 T:3743523664  NOTICE: Creating audio stream (codec id: 86077, channels: 6, sample rate: 48000, no pass-through)
    02:41:53.381 T:4081054544   DEBUG: CAESinkALSA::SelectALSAChannelMap - Selected ALSA map "FL FR LFE FC RL RR NA NA"
    02:41:53.419 T:4081054544   DEBUG: CAESinkALSA::GetChannelLayout - Input Channel Count: 6 Output Channel Count: 8
    02:41:53.419 T:4081054544   DEBUG: CAESinkALSA::GetChannelLayout - Requested Layout: FL, FR, FC, LFE, BL, BR
    02:41:53.419 T:4081054544   DEBUG: CAESinkALSA::GetChannelLayout - Got Layout: FL, FR, LFE, FC, BL, BR, UNKNOWN1, UNKNOWN1 (ALSA: FL FR LFE FC RL RR NA NA)
    02:41:53.419 T:4081054544   DEBUG:   Channel Count : 8
    02:41:53.419 T:4081054544   DEBUG:   Channel Layout: FL, FR, LFE, FC, BL, BR, UNKNOWN1, UNKNOWN1

    There is no indication from Kodi that it's sending 32khz. Is my receiver lying to me about what it's receiving? Or is there some way I can prevent LibreELEC from choosing 32khz as the output sample rate?

    Any leads or directions to check in would be most appreciated. Thanks!

    -KJack