Esp32 i2s audio sampling rate drops while saving file using SPIFFS

Other Hardware Audio
1

Hi there, I'm using esp32-wroom-32e with inmp441 to record audio and save it using SPIFFS. My goal is to send the audio via WIFI and get a response to play. Weird thing is after two conversations, the i2s recording sample_rate drop and the bytes read are almost half of the normal one.

I did delete the old audio at the beginning of each conversation but it didn't work.
I also tried not saving the file and the problem fixed, but thats not what my program was supposed to work.

I did check usage of SPIFFS, my totalBytes is around 1400000bytes, my file is usually around 200000bytes, but the sampling rate still gets buggy after 2-3 conversations.

Can someone give a hint or point a direction? I appreciate all the help. Thanks.

2

Not sure I understand exactly, but it sounds like as you have more data in spiffs it takes longer to complete it's action and that afects the sampling rate.

3

Are you sure the problem is the spiffs? Are you checking the size of the file creating it?

4

i2s works fine if I don't save the file. But when i save the file(file size takes around 20% of the SPIFFS space), real time sample rate drops.

5

No, I try not saving the file using SPIFFS and the problem solved, but it could be coincident.
Yes, I check the file size, it never reach the max limit of SPIFFS.

I would post the code later when I got my laptop.

6

If I have to read minds (since there is no code), you are losing samples. There is no change in sample rate.

Try with 16 bits at 4-6-8 khz sample rate.Your code might be a bit slow to save the data in time.

Try using psram already included in your board.

1 Like
7

The SPIFFS write is very likely blocking.

8

SOLVED. YES 8 khz is good for at least ten conversations.

But I can't figure out the theory deep down. I did output the process of saving data to serial and it seems like it doesn't take long to save the data in time. Is there a way to monitor the actual saving process?

9

use millis() to check that.

Your code is wrong anyways. With 4mb of ram you should save the data to ram, then to a file.

10

This topic was automatically closed 180 days after the last reply. New replies are no longer allowed.