Volumio with Roon Bridge as Plugin can output multichannel through HDMI.
I’ve used Volumio not on a RPi, but on a Sparky and x86-PC and also here the channels are not assigned correctly.
Now I’ve changed to Rock (used only as endpoint), where this problem doesn’t occure.
Linux on PC hardware (like ROCK, Volumio, HQPlayer Embedded, Ubuntu etc) can all do it no problems but Linux on RPi4 hardware (which is what this thread is specifically about) is the challenge.
Sparky is/was a RPi with some changes…
Also I’m using PicorePlayer on a RPi3 with Roon Bridge and HDMI out (until eight channels with 192/24) and there don’t exists the “channel problem”.
I believe that I hear 4 channels. The centre channel seems to be the issue.
I hear more noise when switching to Mch. That is the reason why I am not following it up more.
For 2ch from HDMI, HDCP does not have to be engaged. For Mch it has to be added and a license has to be obtained by the vender. I am not sure if Raspi does have a proper HDMI Mch license. The various experiences with Mch from the Raspi might reflect the developers courage to take a chance. It would be great to read more about this issue.
I’ve explained a few things that right now it’s not on my list. First I don’t have such a device, second I’ve never seen a good implementation: lot’s of engineering bits involved which just cost a serious amount of time. Right now (I’m a ‘2.0 guy’) I don’t see the benefit (and fun) in spending that time.
I have a test track that plays a series of tones in this order: L, C, R, RS, LS. When I send this to the RPi4, the order is incorrect. What’s really strange is that order that I hear sometimes varies from run to run. Also, sometimes channels are skipped entirely.
Last time I tested, this was with DietPi and Roon Bridge. HDMI out into an Emotiva RMC-1L (which may have been the cause of the missing channels. Emotiva firmware is horrible).
Same test track plays correctly on the Intel NUC (running Windows 10) that I have connected via HDMI to the RMC-1L.
As mentioned before: Also volumio on a x86 system will not work correctly in multichannel (test sequences seems ok, but the music mostly not).
Easiest solution is to install Rock (you mustn’t use the core) on a small fanless system. I’m using here a Zotac Nano CI 329, which sends now all the multichannel stuff in every case in a correct way through HDMI.
And again: Picoreplayer is a other solution, which handles multichannel correctly.
I use a Raspi‘s HDMI Output to feed a NanoAvr running Dirac. I feed that NanoAvr on the second port with an Oppo 103 HDMI output. I can not hear a difference between these two HDMI source. So this HDMI jitter is survivable. As the NanoAvr‘s DAC is no that great, I fed the NanoAvr‘s Hdmi output into a Parasound DAC 2000 via an Spdif extractor. While that DAC sounds better than the NanoAvr‘s one, I still do not hear differences between the HDMI routes. So for 2 channels I would say the Raspi HDMI output is good. Are you saying that for Mch that HDMI performance gets worse?
There are not many boxes like the Raspi that allow RAAT to HDMI or ADC to HDMI with a HAT. Hence, it would be great to see this HDMI port to be supported more.
I wouldn’t worry too much about his jitter comment, unless someone shows AVR analogue output measurement showing this jitter is a problem.
The most important point is Harry isn’t interested unfortunately but that’s fair enough. If he won’t use this feature I can understand lack of motivation.
I’m contacting other distros and will let you know if I find something.
I read in several contributions in this thread that you got MCh over HDMI working on Pi3 or 4 with either Volumio or piCorePlayer.
For me only stereo worked so far with my Pi 3B+ - using the distro’s player or via roon. The only combination I was not able to test yet is the roon bridge on piCorePlayer (extra installation hassle).
So what am I missing? Is there special tweaks or settings to be applied?