linuxbashraspberry-pi2omxplayer

Adjust audio volume level with CLI omxplayer - Raspberry Pi


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 command for the CLI that I can implement in the bash script? I have searched quite a bit, but can not find such a command.

Code:

omxplayer Song_Title.mp3

Set audio for local (earphone) output:

sudo modprobe snd_bcm2835 sudo amixer cset numid=3 1

omxplayer -o local

Thanks!


Solution

  • to provide more precise information for playing through scripts, there are 3 ways to change sound volume in current version of omxplayer, and values are not so intuitive:

    1. on starting command line, param --vol YYY, double millibels, default 0, range [-6000:0]
    2. by stdin interface, sending +/- to omxplayer will increase/decrease volume for 300 dmbels
    3. with DBUS interface, cmd 'set volume', value double:XXX, default 1, range [0:1]

    xxx to yyy relation is: XXX = 10 ^ (YYY / 2000) ... according to omxplayer.cpp source code, reverse formula would be: YYY = 2000 * (log XXX).

    so if we need:

    working bash script for dbus volume command:

    export DBUS_SESSION_BUS_ADDRESS=$(cat /tmp/omxplayerdbus.${USER:-root})
    dbus-send --print-reply --session --reply-timeout=500 \
               --dest=org.mpris.MediaPlayer2.omxplayer \
               /org/mpris/MediaPlayer2 org.freedesktop.DBus.Properties.Set \
               string:"org.mpris.MediaPlayer2.Player" \
               string:"Volume" double:0.5   # <-- XXX=0.5 (50% sound volume)
    

    equals to volume parameter at startup:

    omxplayer --vol -602 mediaFileName.mp4
    

    ... both sets sound volume to 50%.