Problem with LFE channel with passthrough via S/PDIF

    Da Flex, I'm still waiting for a new HDMI S/PDIF Splitter to come from interstate after the one they have here was incomplete. However..I remembered a few years ago I bought a Hat. It was for the Rpi3 but it should work on the Rpi4. It's a JustBoom Digi HAT and has S/PFID and digital audio output. If I can get this working it might be a better solution. I just need to find an overlay for it. I'll try adding dtoverlay=justboom-dac.

    Quote from Da Flex

    After dev talk I can say that the audio pass-through is independent of the target device. All available audio channels go out, including LFE.

    The HDMI-1 port should send audio without any settings (user reports somewhere on this forum). Because the splitter is very likely the culprit, you don't need HDMI-1. Just replace the splitter.

    Quote from Da Flex

    Probably that HAT can deal with DTS / Dolby Digital, but I'm skeptical about any HD audio format (you had DTS-HD in the log).

    The receiver amp cant handle anything "HD" so DTS-HD is no loss. I hope the HAT will fit on top of the Argon case. So I might be a physical limitation. I'll find out shortly.

    So the HAT fits OK, red LED power indicator displays. Unfortunately there is no Justboom or Audio DAC option displaying in system audio settings. Seem the card is inactive. I'll contact Justboom and see if is mean to work on the RPi4.

    Edited once, last by chook55: update (September 21, 2021 at 12:33 AM).

    I dont think the card is working. It's not illuminating the optical fiber. Not entry appears on settings.

    The Justboom site shows a ALSA:snd_rpi_justboom_digi, S/PDIF entry should appear in the audio output deice list. see attached.

    I have the following lines in the config.txt

    dtparam=audio=off
    dtoverlay=justboom-dac


    I'll do a search and see if anyone has it working.

    Some success with the Justboom Digi HAT. I now have 2 identical Justboom options to pick. Sampling rate options when these are selected show it automatically restricts it to 48KHz. So passthrough is OK to use.

    2 Channel output works with no pass-through and 5.1 channel with pass-through works.

    And LFE is working. So I have a choice now to keep the HAT or replace the splitter.

    Thanks for your time.

    So I'm using the JustBoom DIGI HAT and using the S/PDIF Optical source to connect to a Marantz Amplifier.

    Dolby 5.1 DTS 5.1 and ATMOS 5.1 sample video files utilize all 5.1 channels with the Audio profile using the JustBoom Digi HAT option. However TV shows and Movies with Dolby 5.1, AAC 5.1 codec are out puting using only 2 channels. I'll reinstall a HDMI SPDIF splitter and remove the JustBoom HAT to see if it's a configuration problem or a firmware problem.

    Yes I'm using the option in the AVR SPDIF (AC3/DTS)[ column.

    If I use the JustBoom SPDIF option as audio out and passthrough device Dolby Sample files play as they should with 5.1 channels. However videos which I know are Dolby 5.1 audio will play as 2 channels only with identical options.

    I havent had opportunity to reconfigure and recommission the HDMI to SPDIF splitter. This I know will play multichannel videos correctly.

    It seems there is a problem detecting the audio encoding, though this shows in the info display widget correctly. I'll be a day or so before I can continue forwards.

    Chook

    OK I have the TV to myself today.

    I discovered a bug.

    I removed the Justboom HAT and config code to temporarily remove any unknowns.

    I used HDMI from the with SPDIF passthrough from my TV set to Optical out. So the TV plays back in 5.1 channels to the AMP from both TV direct first and then through KODI.

    I tested this with my sample DOLBY ATMOS and DTM files. These all played perfectly. I noted that all of these samples are H264 DOLBY or DTM 5.1 channel codec videos.

    When I play H265 encoded files they play in 2 channels only. I checked again with a non demo H264 encoded Dolby Video and 5.1 channels worked perfectly.

    So I suspect there is a bug in that H265 encoded videos are no longer able to decode polyphonic audio. I will re-code one of the H254 DOLBY demo files to x265 and confirm KODI is no longer decoding this properly.

    chook

    My theory doesn't hold true. I converted "THX Deep note Genesis4k.mkv" which never displayed BTW, to HEVC-265 and resized it to 1920x1080. It plays fine. So I'm back to square, one. I try re-coding some of the x265 videos to 265again. See what happens.

    Edited once, last by chook55: Merged a post created by chook55 into this post. (November 8, 2021 at 1:13 AM).