SGTL5000 audio streaming over BLE

[Dipak]

Hello Team,

My end goal is to send 0 to 600hz signal over Ble using NRF52832[ as explained below image].

So, for this, I have used this GitHub code

https://github.com/NordicPlayground/nRF52-teensy-sgtl5000-audio

I successfully played hardcoded car sample audio.

I have already read several topics regarding live audio streaming but as per my application, the input MIC data is very low frequency.

So, I believe as per my application it is possible still, I want to know from your side I m thinking right or wrong?

My problems,

1) how to receive Live MIC data from SGTL5000

2) how to CONVERT I2S DATA into audio. 

3)How to send live audio data over BLE?

Thanks for any help.

[Kenneth]

I don't have any quick guide for you here. The problem with streaming audio is quality and latency, you likely will need to compress the audio also. So I guess you will need to study the different peripheral examples we have in the nRF5 SDK, and try to combine them. For instance there is a uart to BLE that could be used as starting point, you would need to replace uart with i2s, and also look into how to buffer and possible compress the i2s pcm data before they are sent to the peer.

Kenneth

[Dipak]

Hi Kenneth,

Thanks for the reply!

As of now, I have successfully implemented UART to BLE transmission and I have sent 160bytes continuously.

- I want to know how to compress audio data and for that which example I have to follow?

- If I compress the audio data and sent it over to the BLE then after at the receiver side [andriod phone] how to convert compressed data into audio?

Dipak

[Dipak]

Hello,

Are there any updates for me!

Please help!

[Dipak]

Hello Nordic,

Please let me know if is there any update for me!

I am still stuck at that point I don't know how to solve that problem.

Thanks in advance. 

[Kenneth]

I don't have any direct pointers for you. The undertaking of audio over BLE require a lot of work, there is no standardized profile for audio over BLE, so you would need to solve many of the challenges yourself.

Kenneth

[Dipak]

Thanks for the reply!

Using the below GitHub link I have played sample car audio in my custom hardware but

I have one doubt in-car sample.c file  [below-attached Github link]

github.com/.../nRF52-teensy-sgtl5000-audio

Test_case: 1:

when I have sent the car_sample.c hex values on the android side using ble_app_uart service

The car_sample hex values are not played on the android side.

and Yes, I have checked I have received all the data without missing it on the android side.

Test_case: 2:

I have simply manually converted the car_sample.c file to car_sample.raw and imported it into audacity software and tried it with different configuration
but the file is not played.

Please let me know how to convert car_sample.c file into .raw file? 

Thanks in advance!