nRF5340 Audio DK. I want to set to Audio Demo to 3ch sink

[Pio_NSatou]

I have four of these devices. nRF5340 Audio DK.

I would like to use them as follows. Is there a way to set them up?

Device A: source

Device B: sink left

Device C: sink right

Device D: sink center

Each will be connected with CIS.

The audio to be streamed will be 3ch: left, right, and center.

I would like to see it in action as a simple demo, not as a product.

 

I think there are three issues.

1. The chip does not have the processing power to stream 3ch audio.

According to this QA, I understand that multi-channel is difficult due to the chip specs.

https://devzone.nordicsemi.com/f/nordic-q-a/92980/query---nrf5340-audio-dk---configuration-to-stream-multiple-stereo-audio?pifragment-684=1

For example, can this be cleared by lowering the audio quality or some other setting?

 

2.The source output cannot be set to output 3ch.

 

3.The sink set cannot be set to left, right, and center.

I have already confirmed that it can be operated as two sinks (left and right).

It seems that there are parameters like these, but I don't know which ones are valid.

https://developer.nordicsemi.com/nRF_Connect_SDK/doc-legacy/2.5.3/nrf/applications/nrf5340_audio/README.html#cmdoption-arg-CONFIG_BT_ASCS_ASE_SNK_COUNT

[Pio_NSatou]

Mr.Evfving

Dou you know about them?
I hope you check my comment on 2024/12/4.

Pio_NSatou

[Elfving]

Pio_NSatou said:

I set lile this.
nrf\applications\nrf5340_audio\tools\buildprog\nrf5340_audio_dk_devices.json
- source 1:"nrf5340_audio_dk_dev": "gateway","channel": "NA"
- sink 3:"nrf5340_audio_dk_dev": "headset","channel": "right" and  "left" and  "center"
build result is the error on "channel": "center".

I see. So you haven't gotten it working yet, but you have the idea ready made there. 

So there are a few hurdles in the way of getting this working, and you'll have to modify the sample a bit. The buildprog script for instance does not work with the "center" command. My suggestion earlier was to keep one stereo channel for left and right, and other one for center, so if you want to modify the Audio app sample to support this you need to make eg. the left support stereo, and let the other be the one for center. 

So I can look into what would be needed to get this working, but the audio application we have in the SDK does not support this without some modifications unfortunately.

Regards,

Elfving

[Pio_NSatou]

Mr.Elfving
Thank you for your replying.

Elfving said:

the SDK does not support this without some modifications unfortunately.

Does it mean that I can modify it with changing some config files?
If yes, I will try some setting change.All I can do is try blindly.

or Does it  mean that you(Official member) need more detailed research and modifying the entire SDK, including files other than the config file?
If yes, what should I do for your efforts?

Best Regards,
Pio_NSatou

[Elfving]

Pio_NSatou said:

Does it mean that I can modify it with changing some config files?

No, I unfortunately mean you would have to make bigger changes. Though we do have a lot of documentation about the application available which would make this easier for you.

I had a quick talk with the relevant team about this, and it seems that the channel encoding is one problem (as one channel spends 30~33% CPU). But another though would be the input interface, as the i2s only support 2 channels. There's no easy way for nRF5340 to get 3 streams input.

If you are fine using BIS for this (broadcasting, not connected) then you could try using the nRF Auraconfig sample for this, which would be a bit easier regarding testing. That sample uses pre encoded LC3 files from an SD-card, so there is no strain on the CPU for encoding, and you can than use these files instead of an i2s input. Some investigation with a sniffer regarding the air timing to make sure this still works well might be necessary though. 

Either way, there are some potential issues (like audio quality) that you'll have to consider how to address, like eg. lowering the quality of a certain audio channel. 

At this point I would also consider using a second nRF5340, or alternatively the nRF54H20.

Pio_NSatou said:

or Does it  mean that you(Official member) need more detailed research and modifying the entire SDK, including files other than the config file?
If yes, what should I do for your efforts?

My job is helping you, I don't need any more coercion than that :) 

Though it is a bit harder to help you in a situation like this when there are multiple potential issues. If we find a way around these problems, then I still might be a bit limited if it turns out that if we for instance need to (like you mentioned) modify the entire SDK. Though in general, if you need more help from us than what is provided, please contact your RSM about this, and he might be able to help out.

Regards,

Elfving