Thingy 52 microphone

[Miguel Carvalhosa]

Hello,

I am trying to extract audio from the thingy's microphone using the microphone driver. I know that the data it produces is encoded in dvi_adpcm. I would like to decode this data in order to have the audio samples and play the audio.

I tried converting the ADPCMDecoder.java file into C++ and running it in the PC (with the adpcm data retrieved from the thingy via uart), but I am having a hard time, since the output audio is just noise.

Has anyone successfully recovered audio samples from the Thingy? I really appreciated if someone could give me some tips.

Thanks in advance!

[Carl Richard]

Hi, Miguel!

I can ask around internally to see if anyone at Nordic has experience with this. In the meantime I suggest checking out some of the source code for the Thingy:52 user applications, like the android app, to see how microphone data is handled there. You can find the source code on GitHub.

Best regards,
Carl Richard

[Miguel Carvalhosa]

Hi!

Thank you for the suggestion. If you could do that, I would really appreciate it!

Best regards, 

Miguel

[Carl Richard]

Hi again, Miguel!

I got back from one of the developers that ADPCM encoded recordings require some care with regards to framing. It's typically encapsulated into blocks of x milliseconds of audio and a header with encoder state attached. The C++ ADPCMDecoder you're using may expect a certain framing or header format that's different from the one provided by the Thingy:52. Hence, I suggest that you make sure to match the header format that the decoder expects with the one from the Thingy.

Good luck and best regards,
Carl Richard