There are situations where you might want to redirect some audio you're playing on your local computer to another computer's speakers, potentially in a different room, or even anywhere on the Internet.
One of many possibilities to do that is to use the Enlightened Sound Daemon (EsoundD, or esd). It ships with a program called esddsp (apt-get install esound-clients) which can redirect various audio sources.
First, you have to start the esd daemon on a console on the remote host (the one which should output the audio on some speaker, for example 192.168.0.xxx) e.g. like this:
$ esd -public -nobeeps -tcp
You can do this as regular user (no need to be root) if you have the proper permissions. You also need to allow connections on port 16001 in your firewall settings. Then you can redirect audio to that daemon from another computer. In this example I'm redirecting some music using various players:
$ esddsp -s 192.168.0.xxx:16001 mpg321 -o esd foo.mp3 $ esddsp -s 192.168.0.xxx:16001 mplayer -ao esd foo.mp3 $ esddsp -s 192.168.0.xxx:16001 ogg123 -d esd foo.ogg
This also works fine for videos, in which case you can redirect the audio (but not video):
$ esddsp -s 192.168.0.xxx:16001 mplayer -ao esd foo.mp4
For the video player Miro, I've recently documented this in the Debian package's README.Debian file. Basically you have to edit ~/.xine/config and enable audio.driver:esd there, then start Miro with
$ esddsp -s 192.168.0.xxx:16001 miro
Audio will be emitted on the remote host, video remains on your local PC.
Some programs may also support esd natively, in which case esddsp is not required, e.g.
$ ogg123 -d esd -o host:192.168.0.14:16001 foo.ogg