Adjust audio volume level with CLI omxplayer - Raspberry Pi

Question

I have a bash script that plays .mp3 files on my Raspberry Pi via omxplayer. But can not control the local (earphone) audio volume with the GUI. Is there a comm

Answer 1

Omxplayer doesn't use alsa for sound output, but it's possible to use stdin interface

Volume up:

echo -n "+" > /proc/$(pidof omxplayer.bin)/fd/0

Volume down:

echo -n "-" > /proc/$(pidof omxplayer.bin)/fd/0