Using HDMI for 5.1 audio output on a headless Pi

Plex Labs
1

Revisiting this topic.

I have spent many hours over many days trying to get a Pi, any Pi, to properly output 5.1 audio via HDMI using headless plexamp. I have never gotten this to work.

I have gotten 5.1 audio out of plexamp with use of a hat, and I thank the community for their attention and help to getting that far. But I do wish to also make use of my plex library on HDMI devices as well, and this problem has been a brick wall to unleashing the true possibilities of plexamp.

I do not understand why this topic has gone ignored for so long - has no one ever made use of HDMI around here? It’s quite baffling.

I’ve played around with Pi3 and Pi4, I’ve gone around in circles with many configurations and tweakings. But the bottom line is, the only thing that I’ve gotten is that, plexamp will playback 5.1 audio content out the default audio output, which the Pi OS is configured to use the HDMI as the default, my receiver sees a 5.1 digital signal coming from the Pi, but my receiver plays back the audio with no center channel information.

I know my files are properly formatted, several other devices can play them back properly.

I know my receiver/speakers are configured properly, I can playback HDMI 5.1 audio from many other devices without issue.

I suspect plexamp is handing off proper 5.1 signal to the OS given that my Pi5 with hat is able to playback 5.1 properly, although the configuration on that device is rather specific to the hardware, so I can’t confirm that plexamp’s handling of the audio to the OS isn’t the problem.

I pushed very hard on the problem lying with Raspberry Pi’s handling of HDMI in their OS, but their people have been completely useless in troubleshooting, and are only interested in showing useless screenshots that suggest HDMI works fine, without actually addressing the details and data I’ve provided. It’s impossible to get anywhere from them because they refuse to acknowledge there’s an issue. There clearly is an issue - I playback audio, no center, that’s an issue.

So I beg of you, for the love of almighty, please someone spin up a Pi3 or Pi4 to playback 5.1 audio from plexamp out the HDMI of the Pi, and confirm there is a problem, and perhaps figure out what the next steps are to come up with a way to make this work as it should.

2

Bump. Don’t want this to get closed out and forgotten again. I would expect that basic functionality on a widespread device that this app was designed to work on would be of enough importance to warrant the most basic of testing, I have to say I’m rather surprised at the complete lack of care of whether or not the audio output works for an app that is designed specifically to play audio.

3

Following up on this.

Still looking for the basic functionality of accurate audio output from an app designed for the playback of audio.

It seems ridiculous that such a basic request is going completely ignored here! What use is an audio app that can’t playback audio correctly?
Really hope we can get a working version of this someday…

4

Is everyone still refusing to acknowledge the hdmi audio output of a Pi as an important audio output? You can’t be bothered to even so much as look into why plexamp isn’t working correctly with this?
What kind of a joke is this?

5

Bumping this.

6

So first thing’s first, are you trying to play back surround-encoded music? Because the vast majority of music is encoded in stereo. So Plexamp is doing exactly what it’s told to - sending two channels to your AVR.

If you want 2-channel music coming out of all your speakers, you need to do that on your AVR - generally called something like “Stereo Surround”.

If you are trying to playback 5.1-encoded audio, then there’s a chance that Plexamp isn’t built to decode that because of how niche it is.

7

For playback of 5.1-encoded audio via HDMI, you can use KODI.
Personally I only have one album with 5.1-encoded audio, dark side of the moon.

1 Like
8

I am absolutely playing back properly encoded 5.1 surround music.

I have gotten a Pi to playback 5.1 properly with the use of a HiFiBerry DAC8x, which is good for situation in which you want to setup playback in a setup in which HDMI isn’t an option. This works well in my car.

However, I would like to make use of my 5.1 library around the home on my home theater setups, in which HDMI is essential. When I try to setup a Pi with plexamp, and configure it to use the HDMI out, I continue to run into problems. The best I can get is for it to playback the 5.1 with the center channel completely missing. (The sub may or may not be present, I’m not sure, as the missing center is immediately noticeable and what I’m currently diagnosing and working on.)

I’m not sure if this is a function of the Pi not playing back the signal it is receiving from plexamp properly, or plexamp not sending the signal properly. But either way, plexamp isn’t working, and through all my efforts going around in circles I’ve not had much luck finding any widespread documented issues in Pi’s HDMI ports being broken, which leaves plexamp the likely culprit.

I’d hardly call 5.1 niche. Heck, it’s a challenge to find a home theater that does only 5.1, with 7.1 and atmos growing in use. My library contains over 800 5.1 surround albums.

9

I’d hardly call 5.1 niche. Heck, it’s a challenge to find a home theater that does only 5.1, with 7.1 and atmos growing in use. My library contains over 800 5.1 surround albums.

I meant 5.1/surround music. Obviously 5.1 has been a standard for movies and TV for decades.

Even getting Plexamp to output the audio over HDMI is a pretty decent feat that required a lot of fiddling for my HDMI → Optical extractor solution, so kudos on getting it that far.

As for getting it to function, I would start at the OS. Have you tried running a 5.1 sound test on it to test if the Pi’s ALSA/Pipewire/Pulse setup is even correct? If you do some googling, you’ll be able to find some command-line packages that will be able to push a sound test to each channel so you can confirm that the OS is configured correctly.