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

[Elfving]

Hello,

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

First of all, you are somewhat right in this. If you want 3 different streams set up from one source that might be a bit much for nRF5340 to handle. There is a rule of thumb which states that nF5340 wuld spend about 30% of its computational power on one of these streams with 96 kbps. So if you would even do 2 of them, you need to make sure that you are not doing anything too intensive in addition to that. 3 however would easily be a bit much if you want anything on top of this. It is also rather common to want some further audio processing in addition to sending out the streams themselves, so this is important to keep in mind.

Its also true that one could theoretically decrease the quality from 96 kbps. You could also simply back the left and right streams into one stereo CIS stream, meaning that you essentially have two streams here. 

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

Yeah there is some limitation there as well which I believe depends on the controller used. Could you tell me where you found this?

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

Meaning all of them at the same time? I thought that should be possible.

Try adding a center one in addition to left and right. Have one stereo CIG for the left and right channels, and let the last mono one be your sink center.

For more on how to configure them for this, see here.

Regards,

Elfving

[Pio_NSatou]

Hello Mr.Elfving
thank you for your answer.

I reply your question. and I ask more question.

Elfving said:

Its also true that one could theoretically decrease the quality from 96 kbps.

How should I do? for example, these parameter?
https://docs.nordicsemi.com/bundle/ncs-2.0.2/page/nrf/applications/nrf5340_audio/README.html#cmdoption-arg-CONFIG_AUDIO_SAMPLE_RATE_HZ
same url CONFIG_AUDIO_SAMPLE_RATE_HZ/CONFIG_AUDIO_BIT_DEPTH_16/CONFIG_ENCODER_THREAD_PRIO

Elfving said:

Yeah there is some limitation there as well which I believe depends on the controller used. Could you tell me where you found this?

I only just try like this link, channel as "left" , "right"  and "center". The build can't work.
https://docs.nordicsemi.com/bundle/ncs-2.0.2/page/nrf/applications/nrf5340_audio/README.html#preparing_the_json_file

So would you tell me how to set source device?

Elfving said:

Try adding a center one in addition to left and right. Have one stereo CIG for the left and right channels, and let the last mono one be your sink center.

I checked all of your URL Link. but I don't know where to find useful information for my situation.
So would you tell me how to set sink device?

[Pio_NSatou]

Let me give more information about my situation.
See this picture.
I have already created a 3ch sound source.
The left, right and center structure can be said to be the first, second and third channels in other words.

[Elfving]

What NCS version are you using. I see that you are linking to documentation for NCS 2.0.2, I just wanted to mention that I would definitely recommend using newer NCS versions for Audio, at least NCS >=2.6.0, due to how rapidly the LE Audio support is evolving. 

Pio_NSatou said:

I only just try like this link, channel as "left" , "right"  and "center". The build can't work.

Pio_NSatou said:

I have already created a 3ch sound source.
The left, right and center structure can be said to be the first, second and third channels in other words.

I'm not sure if I understand. How did you set up this 3 channel system? 

Pio_NSatou said:

How should I do? for example, these parameter?

Yes use those. CONFIG_AUDIO_BIT_DEPTH_16 gives you 16bit. 16*48khz = 96kBps.

Regards,

Elfving

[Pio_NSatou]

Mr.Elfving
Thanks for the advice.

I'm using NCS ver2.8.0.
And I see the latest documentation.nRF5340 Audio applications

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".

And yesterday, I tyied like this.
nrf\applications\nrf5340_audio\unicast_client\Kconfig.defaults
- config BT_MAX_CONN    default 2->3
- config BT_MAX_PAIRED    default 2->3
- config BT_BAP_UNICAST_CLIENT_ASE_SNK_COUNT    default 2->3
- config LC3_ENC_CHAN_MAX    default 2->3
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  "right"
build and running is success.
but they don't work as 3ch. Source device connects to 2 sink devices, 1 sink device as "right" is not connected.

Elfving said:

Yes use those. CONFIG_AUDIO_BIT_DEPTH_16 gives you 16bit. 16*48khz = 96kBps.

Thank you. I will add it in nrf\applications\nrf5340_audio\prj.conf.

 

As I said above, I am still having issues.
The 1 source device does not connect to the 3 sink devices.
Would you help me?