Query - nRF5340 Audio DK - Configuration to Stream Multiple Stereo Audio

Question

Hello, 
 I have 3 nRF5340 Audio DK. With the steps mentioned in below links, I configured Json file to stream left/right audios and I'm able to achieve it. 
 https://developer.nordicsemi.com/nRF_Connect_SDK/doc/2.0.2/nrf/applications/nrf5340_audio/README.html https://www.youtube.com/watch?v=ZtNflUO8IC0 
 How to stream stereo audio to 2 sink DK from a source DK? How to do multi-streaming to 3 or more DK? (Usecase: I want to stream 4 separate audios at a same time to 4 separate sinks from a source) 
 Thanks

Maria Gilje · Accepted Answer

Bala4nRF said: I see Bluetooth SIG community mentioned max limit of CIS to be 31. Here does left and right channels contribute 2 CIS or they combine to form 1 CIS? 
 The limit of 31 CIS in one CIG is from the Bluetooth specification. For the LE Audio Controller Subsystem for nRF53, the maximum CIS per CIG is two. Also, there is a maximum of two ACL links with the nRF53 LE Audio controller. Each ACL link can control one CIG or both CIS in the same CIG separately. 
 The left and right channels can be combined to form 1 CIS. 
 Bala4nRF said: How can I connect 3rd(2nd) CIS to 3rd headset(nrf5340 DK) from gateway(nrf5340) with new audio channel(not the left and right channels which is active in 1st CIS) 
 This is not possible with the current controller. Each connected device needs an ACL and the maximum number of ACL links is 2. The BIS mode is the only mode supporting streaming to more than two devices at this point. 
 Bala4nRF said: With nRF5340 user guide, I could only see that the configurations can be set to transmit same audio(left/right) to 'n' no of headsets(DK) using CIS. 
 Yes, this is the way the application implements stereo -- two kits needed for left and right output. You can modify the application to be able to stream stereo by combining the left and right channel after encoding and before sending the audio. In the application code, the combination needs to be done before streamctrl_encoded_data_send() is called in the encoder_thread() in src/audio/audio_system . 
 Bala4nRF said: My motive is to stream multiple audio tracks(2 diff song) through different channel to different DK, 
 Two different songs with stereo audio will need four channels to be encoded, which will surpass the processing power available. You are free to test if a lower sample rate for the audio will make the processing power decrease enough to make it work. This is just speculation from my side, though. 
 Kind Regards, Maria

Query - nRF5340 Audio DK - Configuration to Stream Multiple Stereo Audio

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