OPUS encoder sampling rate upper limits

[msat]

Hello,

I recently started looking through the Smart Remote 3 code as I'm interested in potentially using a suitable nRF device + I2S ADC to encode and stream music using OPUS/CELT. Since I'm new to nRF products, there's a lot to digest here. Looking at sr3_config_nrf52832_custom.h, max sample rate is listed as 32kHz, and in drv_audio_codec_opus.c, the highest frequency is 24kHz.

What is the reason for these limits in the code? Is it RAM and/or CPU limitations? Is 48kHz sampling rate a possibility?

Thanks,

Mark

[Kenneth]

The smart remote 3 was designed to transfer audio commands, not music, so the quality just needed to be good enough for the purpose and of course a trade-off between throughput/latency/power consumpton. I am not aware of any reason using better quality should not work (given you don't care about latency), but it's 3 years since it was launched, so I don't expect the developers have all the details anymore, I suggest if you want to change anyhthing you try it out and work through the issues you may see, it might also be that RAM/CPU will be the bottleneck.

Kenneth