Multiple roles for audio

[Adarsh_1]

Hello,

I would like to know if the application / use case stated below is implementable.

In my application I would like an nrf52840 to communicate with the Bluetooth module in a Raspberry Pi (Central). Raspberry Pi will send the nrf52840 with a mixed digital audio signal. Later the nrf52840 device will decode the mixed audio signal to three separate channels and then send these three separate audio to three headsets (with nrf5 SoC). nrf52840 will have to act as central and peripheral role and at the same time.

The most critical aspect is that the audio sent to the three headsets are different. Can I establish a connection with three peripheral device and send three different audio signals to these three peripheral device from a single nrf52840 at the same time? 

I will very well appreciate your help. 

Thank you.

Best regards

Adarsh

[Karl Ylvisaker]

Hello Adarsh,

Raspberry Pi will send the nrf52840 with a mixed digital audio signal.

What is the bitrate of this transfer?

Can I establish a connection with three peripheral device and send three different audio signals to these three peripheral device from a single nrf52840 at the same time? 

It is hard to answer anything definitively without knowing any specifics the system as a whole - such as what audio quality you need - but the answer is in all likelyhood: no, this is not possible on a nRF52840.

For the record, we recommend the nRF5340 for LE Audio development, but even the nRF5340 might not be enough for the scenario you describe.

Best regards,
Karl

[Adarsh_1]

Hallo Karl,

Thanks for your feedback. 

Karl Ylvisaker said:

What is the bitrate of this transfer?

The bitrate is not defined at the moment. However the audio quality can be compromised here.

Karl Ylvisaker said:

For the record, we recommend the nRF5340 for LE Audio development, but even the nRF5340 might not be enough for the scenario you describe.

As a whole, I would like to know the practicability of the use case. Is it possible for a Bluetooth device to send three different audio to three different headset (peripherals) in any case? Even when using Bluetooth Classic? 

Basically is there a way for a single mobile application to send three different audio to three different headsets at the same time via Bluetooth?

Thanks for your help.

Best regards,

Adarsh

[Karl Ylvisaker]

Hello again Adarsh,

Adarsh_1 said:

Thanks for your feedback. 

No problem at all, I am happy to help!

Adarsh_1 said:

The bitrate is not defined at the moment. However the audio quality can be compromised here.

You mention that these are headset peripherals, which makes me believe the use case is not feasible because the audio quality would have to be much lower than than what is needed for speech for this to work at all.

Adarsh_1 said:

Is it possible for a Bluetooth device to send three different audio to three different headset (peripherals) in any case?

The answer to this question is not certain, because it would heavily depend on the quality of the streams being very low, if it were to be possible.
LE Audio comes with the Broadcast audio feature, which will let the device broadcast audio to any amount of peripheral devices.
However, it gets more tricky when you need 3 different audiostreams, since each will require its own encoding which is very resource intensive in and of itself.
It is the initial stream reception over BLE and encoding of 3 different streams that would be the bottleneck for the use-case you describe.
To make this feasible you might have to offload some of the work to another MCU, like having the encoding happen elsewhere.

Adarsh_1 said:

Even when using Bluetooth Classic? 

You would have to ask in a Bluetooth Classic forum about this, as none of our products supports Bluetooth Classic and thus we have very limited experience with that here on DevZone.

Adarsh_1 said:

Basically is there a way for a single mobile application to send three different audio to three different headsets at the same time via Bluetooth?

You might be able to do this with LE Audio, but I am uncertain if the simultaneous encoding of the 3 streams could be too resource demanding. Adding the BLE reception of the initial stream into the mix makes me certain that this is not feasible, even with a nRF5340.

Best regards,
Karl