rec FAIL sox: `default’ Device or resource busy: Operation not permitted

• System Environment：

   Static hostname: orangepizero
         Icon name: computer
  Operating System: Armbian 20.11.3 Focal
            Kernel: Linux 5.9.14-sunxi
      Architecture: arm`enter code here

root@orangepizero:~# rec test.mp3

Input File : ‘default’ (alsa) Channels : 2 Sample Rate : 48000 Precision : 16-bit Sample Encoding: 16-bit Signed Integer PCM

In:0.00% 00:00:00.00 [00:00:00.00] Out:0 [ | ] Clip:0 rec WARN alsa: Input/output error rec FAIL sox: `default’ Device or resource busy: Operation not permitted In:0.00% 00:00:00.00 [00:00:00.00] Out:0 [ | ] Clip:0
Done.

Answer

Try using the ALSA dsnoop plugin to record from an audio device which is already in use.

To specify the audio device using sox’s rec command line application, use the “-t” flag like so :

rec -t alsa dsnoop test.mp3