Aac audio over nrf 52811

[Tomas Adri]

Hi

Spotify 128 kbps aac stream is about 16 bytes per ms. Ble should support 31 bytes per packet. 

So can I stream 16 bytes ms over lte m to nrf 9160 then via uart to nrf 52811 and then to AirPods Pro 2? No encoding or decoding, just simple aac all the way

[Susheel Nuguru]

BLE connections is acknowledge based and the quality of the audio will significantly deteriorate even with the increase of small distance between the audio source and the Airpods. The user will be able to notice this. Instead you need to rely on more specific BLE audio solutions. I cannot recommend you any other way for actual Bluetooth audio streaming (irrespective of speed) other than our Bluetooth LE Audio solutions.  If you want to do some quality experiments on your own, I think 52811 have too little memory to use it as a playground for this. Maybe talk to the RSM of your location for more options to explore (if you have not done that already)

[Tomas Adri]

Yes we will try. If we send a 251 byte packet each 7.5 millisekund that is 32 000 bytes per second or ca 256 kbps that is enough for highest Spotify 256 aac. Maybe we even can send 2 or 3 packet per 7.5 ms intervall ? I think the 24 KB ram is more than enough, and the distance to the Airpods Pro 2 i under a meter and maybe we can buffer some in the AirPods.

[Susheel Nuguru]

You can try, I think many have tried this before already. It is  important to note that using regular BLE services and characteristics for live audio playback can have some issues, especially the lossless feature of the BLE link. This can result in a backlog of 'old' audio packages that need to be sent in order to catch up with the live stream, even at few meters, there can be a lot of dropped packets based on the environment and other 2.4GHz air activity of your device. I cannot officially suggest you this route of prototyping, but you can definitely give it a shot and observe the quality and power implications of this.