HDMI Splitters and audio

    So, searching, I've not found anything that already addresses this.

    I have the X64 flavor of LibreELEC (10.0.0.3 Matrix) running on a Chromebox. This is connected to an HDMI splitter (and audio extractor), in turn feeding an AVR and projector.

    Whichever device that is plugged in the "first" HDMI output port of the splitter is what is detected in the System/Settings as the audio device.. I currently have my AVR plugged in to that port, so that's what's reported as HDMI0: "AVR"

    What's odd is that if the projector (on the second port, not detected by LibreELEC), I get no sound from the AVR connected via HDMI. If I power the projector off... I get audio.

    Swapping ports (and the projector thus being detected on HDMI0) likewise renders no sound routed to the AVR, as I would have expected. in both cases I get video on both output ports.

    So... any thoughts as to why even thought the AVR is what is being detected, the mere presence of the projector on the other (non-detected) port screws this up? The projector actually does have audio capabilty (RCA jacks), so my guess is that for some reason audio is being routed there regardless...

    The previous 2 devices connected to the same splitter (both Windows PC's) had no such issue, so I know the devices are capable of it....

    Thanks.

    What kind of splitter / audio extractor are you using?

    The splitter needs to mix the EDIDs of both the AVR and and projector, LibreELEC heavily relies on that being accurate and it is quite likely Windows was more relaxed about it.

    My HDFury Vrroom has very extensive settings how it'll mix (or patch up) the edids and also allows you to download the edid directly via the web interface.

    You can also grab the edid presented to your chromebox from /sys/class/drm/cardX-HDMI-A-Y/edid (A, X, and Y may vary on your system) and decode it with edid-decode. eg

    Code
    edid-decode /sys/class/drm/card0-HDMI-A-1/edid

    if you have multiple cards or connectors (A-1, A-2 etc) try all of them and post the output (the unconnected HDMI ports will show "empty" - just ignore them).

    so long,

    Hias

    Got a chance to try dumping the EDID stuff. Sure enough, whenever just the AVR is the only device plugged in to the splitter, I see the various multi-channel audio capabilities it has in the audio data block of the EDID data.

    When the projector is also plugged in to the splitter, the AVR data goes away and just the 2 audio channels of the projector are in the Audio Data Block. Swapping output ports on the splitter makes no difference.

    So, this begs the question: is there any way to manually specify what/where to send the audio data.

    Failing that, any recommendation for a better behaving HDMI splitter + analog audio extractor?

    EDID dumps attached

    Thanks.

    Your splitter is the problem (it is masking the audio capabilities).

    But you should be able to workaround it.

    Capture the correct edid (when it is just connected to the AVR) with getedid.

    You should then be able to plug in the projector and still have LE see the good edid in the future.

    (The captured edid will survive reboots).

    Cool.. used that method to grab the EDID with the AVR, and it now works even with the projector connected. Thanks.

    One thing I notices (and I didn't describe in my initial post as it wasn't a factor regardless of connection state), is that a monitor that attaches to the second video port (DisplayPort alongside the HDMI) running in mirror mode seems to now overscan a bit.

    I suspect it may be possible to grab the EDID data with the DisplayPort monitor attached/detected and make that work... or if not, grab the EDID's from each attached separately and merge them...