I have a minix U9H running CoreELEC from a micro SD. It is connected to my Sony SA-RT5 AVR via HDMI cable. I can’t output AAC 5.1 to the AVR; it reports 2 channel PCM input.
In an earlier thread i was kindly advised by Sholander:
On my boxes I set in Settings/System/Audio: Number of channels = 2 Allow passthrough, and set "Enable Dolby Digital (AC3) transcoding to ON
I followed those instructions and they fixed the problem, but recently, the sound is defective - it is distorted and keeps dropping in and out. Most of my video files are DTS, AC3 or EAC3 and they work fine. Any ideas what the problem is now/ what i might have done to confound the earlier solution?
Most AVRs (including your Sony RT5) cannot decode AAC audio over HDMI. Most Dolby and DTS formats are ok to passthrough, with pricier AVRs being able to handle the more exotic Dolby and DTS formats.
Your Kodi settings should be set to convert AAC to PCM. I’m not sure what specific audio options are presented on your minix, but I would be setting the number of channels to equal the number of speakers handled by your AVR and set PCM multichannel for the HDMI output. Then, only passthrough to your AVR those formats actually handled by it - Dolby Digital
Dolby Digital Plus
Dolby TrueHD
DSD
DTS
DTS-ES Discrete 6.1,
DTS-ES Matrix 6.1
DTS96/24
DTS-HD High
Resolution Audio
DTS-HD Master Audio
Thanks, i realise i must transcode to a format that my AVR accepts. And all was working fine for some time. Now - no matter what combination of settings i choose - the ONLY settings that produce any sound at all (and my AVR reports as 5.1) are those i have mentioned, specifically:
Default Estuary skin.
Player Settings
Disable Sync Playback to Display
System Settings (Audio)
Output device ALSA:AML-M8AUDIO, HDMI
Number of channels 2
Output configuration Best Match
Allow Passthrough
Enable Dolby Digital(AC3) transcoding
Passthrough Output Device (greyed out) ALSA:AML-M8AUDIO, HDMI
I’m not near my CE box at the moment, but from memory my N2 uses HDMI Multi Ch PCM as the output device and I set the channels to 5.1.
My passthrough device is set similar to yours and this handles all the usual Dolby and DTS variants including HD.
However, I do not have Dolby transcoding set, so anything not handled natively by my AVR (like AAC) is sent as multichannel PCM. I think your passthrough device is greyed out because you are transcoding.
The only HDMI “output device” setting option that i have is ALSA:AML-M8AUDIO, HDMI.
Below, I can set the “number of channels” to 5.1, but that doesn’t work. It makes no difference or gives no sound at all depending on which of the myriad other options i choose.
Ok - it’s probably a limitation of the box. My N2 has HDMI Multi Ch PCM and that works perfectly for me with my multichannel FLAC audio files right up to 192kHz 24 bit. For movies etc., I mostly use passthrough and all formats, including Dolby Atmos are sent to the AVR.
I think there may indeed be a problem with my installation. It has been hanging for a long time on start up. Maybe the card is degrading?
I have an entirely different set up in another room: cheap android box to a Marantz AVR and that reports AAC as Dolby digital i.e. 5.1 routinely - just with pretty much default settings (with passthrough). An older version of CE too ( 9.0.2 vs 9.2.8)
It’s depressing because as an ageing non-techy, i have to relearn the method every time and it’s quite a few years since i last did it
Are you sure, you didnt change anything on your setup?
Even just plugging in new stuff can break things with HDMI.
If you can, get a new micro sd card and make a fresh install, unplug every unnecessary HDMI connection to test. (to have a simple setup like TV ->AVR → U9H.)
Also try out other HDMI cables if you can.
I also used the U9H, I never seen it outputting multichannel PCM. (seen Stereo PCM max)
All Passthrough able formats like DD, DD+, DD TrueHD, DTS and DTS HD worked fine.
Files with AAC just played as Dolby (AC3), I also never seen the option “Enable Dolby Digital (AC3) transcoding to ON” on this device, with the 9.2.8 version. (I guess, it’s on by default in this version, but I don’t know.)
The “HDMI Multi Ch PCM” is just an option on newer devices like the Ugoos AM6B+ (S922x) or Minix U8K-Ultra (S928) or other devices, that run the up-to-date version of CoreElec.
I have a feeling the AAC problem may have been a bit of a red herring. Last night it refused completely to boot past the CE screen. So I booted into Android and I ran Kodi perfectly successfully under that OS - including perfect AAC (Dolby) 5.1 output (with transcoding set to off). So i guess a fresh CE install on a new card is the way forward?
BTW - stupid question from a non-techie - is the Kodi running under CE the same actual program as that running under Android, or does the micro sd card carry a ‘dedicated’ version of Kodi to run under linux as well as the OS?
There are several versions of same Kodi builds for different platforms
Settings are almost the same across all platforms, and if AAC 5.1 works on your Android version, it should also work in your CE/Linux version.
So, if i understand you correctly, the micro sd card comprises the CE (linux) operating system as well as a version of Kodi to run under that (linux) operating system?
Perhaps therein lies the original problem. Kodi on android works perfectly but not in CE. The audio settings are the same, but ‘output device’ in Android is ‘greyed out’ and “Android, audiotrack” is the mandatory option. If this is the root of the problem, presumably it would suggest it’s a shortcoming of the CE app rather than the box?
BTW, i installed a fresh CE on a new sd and it now boots perfectly, but the AAC problem remains.
How then you explain the behavior you wrote in your initial post “I followed those instructions and they fixed the problem, but recently, the sound is defective” ?
How can CE make sound “defective” only for you, and not for anybody else?
That’s a very good question! I wonder if i was mistaken. Almost all the files i play are mkv. Or it could be that it’s a different AVR. I got this one in about 2020 (for the eac3 input) and i believe the helpful instructions that you yourself originally gave me (in greater detail than i put in my first post) were from before that. I think i was outputting over sp/diff then too.
I guess i could always dig the old AVR out and give it a go. But we are where we are. I’m not trying to impugn CE, but the ‘simple’ fact is that AAC 5.1 ‘works’ under Android but won’t work under CE no matter what settings i try
