If omxplayer's auto-detection of the correct audio output device fails, you can force output over hdmi with:
$ omxplayer -o hdmi example.mp3
or you can force output over the headphone jack with:
$ omxplayer -o local example.mp3
To troubleshoot the sound module::
$ lsmod | grep snd_bcm2835
$ sudo modprobe snd_bcm2835
To load the sound module automatic:
cd /etc
sudo vi modules
# /etc/modules: kernel modules to load at boot time.
#
# This file contains the names of kernel modules that should be
# loaded at boot time, one per line. Lines beginning with "#" are
# ignored. Parameters can be specified after the module name.
snd-bcm2835
By default the output is set to automatically select the default audio interface (HDMI if available otherwise analog). You can force it to use a specific interface using :
$ amixer cset numid=3 n
Where <n> is the required interface : 0=auto, 1=analog, 2=hdmi. To force the Raspberry Pi to use the analog output :
$ amixer cset numid=3 1
To play a WAV file using aplay:
$ aplay police_s.wav
To play an MP3 file using mpg123:
$ sudo apt-get -y install mpg321
$ mpg321 bubbling_water_1.mp3
$ mpg321 -g 50 bubbling_water_1.mp3 # [ volume 50% ]
To play a MP3 file using Imxplayer:
$ sudo apt-get -y install omxplayer
$ omxplayer bubbling_water_1.mp3
The plus (+) and minus (-) keys can be used to adjust the volume of the playback.