2017 NUC; Disabled Passthough; PCM passes 2 channels Without Vocals

1st Official Post

    Hello,

    I understand that there is currently no support for audio passthrough on the newest (possibly older as well) Intel NUC models.

    As others have suggested, I disabled passthrough, expecting to let Kodi decode the audio and pass it to my receiver via PCM.

    Even though I have selected 5.1 channels under System Settings ----> Audio, my receiver reports that it is receiving PCM 2.0 audio. I hear only ambient sound from these two channels, making LibreELEC in its current form ENTIRELY unusable.

    All of my videos have only one audio track: either DTS-HD Master Audio, or Dolby TrueHD, so I don't believe optical is an option, unless PCM makes it an option.

    I'm running LibreELEC 8.0.

    I just tried to export a log but it's giving me an issue.

    Any idea? I really wanted LibreELEC to be the primary operating system on my NUC.

    PS Windows handles the audio fine but is of course much less friendly as a HTPC OS.

    Hi..i am a new user here. As per my knowledge PCM is Pulse Code Modulation and is uncompressed audio. In general you cannot assume PCM is inferior as it can spit out up to 8 channels of audio and much higher bit rates than Dolby Digital . I don't know exactly what TiVo outputs as PCM though but it sounds like it may be more than 2 channels. I think some audiofiles actually prefer to use PCM output from Blu Ray players for example.

    pcb assembly china

    Edited once, last by LulaNord (March 17, 2017 at 5:45 PM).

    Yes that's correct - which is why I mentioned that I am fine with allowing Kodi to output PCM. (Long-term I prefer the visual confirmation of audio format on my receiver.)

    The problem is that, with Kodi set to 5.1 or 7.1 channels, my AVR reports receiving only 2 channels over HDMI.

    Reboot to Windows? Full 7.1 out.

    But again, there is a problem with the audio driver on the NUC for Linux at the moment, so I'm just trying to find out why LibreELEC is seemingly mishandling PCM output.

    I promise I'm not trying to be a jerk about this, but would it help to contact Kodi directly regarding this issue?

    I'm really trying to solve a problem here, and I don't know if they can help me or not, but (based on zero answers to the specific question) nobody seems to know why LibreELEC will only output 2 channel audio from the Intel NUC.

    I'm wondering if I'm not explaining it well enough?

    The ALSA output identifies my receiver by brand/model.

    Passthrough: No Audio (Known Issue)

    Passthrough Disabled: 2 channels (PCM) only - I was mistaken earlier when I said there were no vocals - the setting on my AVR was processing the audio in a special way.

    The bottom line: I cannot get LibreELEC to put out more than stereo PCM.

    Please, someone point me in the right direction! Thanks!

    Well, I assume I can't help you directly on this, but I'm at least also a 2017 NUC user (NUC7I3BNK). In my case HD audio format passthrough is also not working, but DTS and AC3 passthrough is. In addition I'm pretty sure PCM also does it's job for HD audio formats. I selected 7.1 channels in Kodi, but I only have a 5.0 setup at the moment. I can check again if PCM works for more than two channels when I'm back home.

    Edited once, last by Jeremia (February 23, 2017 at 12:45 PM).

    Quote from Jeremia

    Well, I assume I can't help you directly on this, but I'm at least also a 2017 NUC user (NUC7I3BNK). In my case HD audio format passthrough is also not working, but DTS and AC3 passthrough is. In addition I'm pretty sure PCM also does it's job for HD audio formats. I selected 7.1 channels in Kodi, but I only have a 5.0 setup at the moment. I can check again if PCM works for more than two channels when I'm back home.

    Actually, thank you - you made me realize that I should try turning on passthrough but disabling the DTS-HD and TrueHD switches; most devices (my Nvidia Shield for example) will pass the core of a DTS-HD track (regular DTS) if it has trouble passing the HD version, but maybe LibreELEC or the NUC can't do that.

    I think I already tried selecting 7.1 (even though I only have a 5.1 system) and that didn't work, but I'll do some more testing.

    I'm fine with regular DTS or AC3 for the time being, IF there is a solution in sight. Moving forward, though, I have to figure out if the Linux community (and/or LibreELEC) is going to figure out a way to make HD audio work. These sound formats (DTS-HD Master Audio and Dolby TrueHD) are a decade old and shouldn't be difficult to handle, but it's far beyond my own capabilities to create the solution myself. Intel is getting ready to patch their NUC Windows audio driver for the NUC to allow current-generation formats DTS:X and Dolby Atmos (which are already almost 5 years old in truth) within a month!

    LibreELEC is absolutely fantastic in so many ways (especially file sharing), but regardless of whether it's a driver issue or a coding issue, I have to focus my efforts on a platform that works. Right now, the only environment that has absolutely zero issue taking full advantage of the NUC's audio capabilities is Kodi for Windows. I highly doubt the Linux community is going to be ready for DTS:X and Dolby Atmos within 30 days - but I am! :)