Sound over HDMI

This info is not tested but was found here:

HDMI and S/PDIF audio output

When diagnosing sound problems, make sure that pulseaudio is not running:
sudo killall pulseaudio
Please also make sure that no other program might be using the soundcard: disable system sounds, kill all web browsers (to kill the flash player), and kill all media players.

To get default audio output on the analog stereo jack, run
$ mplayer -ao alsa $FILE
To force audio output on the analog stereo jack, run
$ mplayer -ao alsa:device=front=NVidia $FILE
To force audio output on HDMI, run
$ mplayer -ao alsa:device=hdmi=NVidia $FILE
To force output on S/PDIF, run
$ mplayer -ao alsa:device=iec958=NVidia $FILE
To list all available audio output devices, run
$ aplay -L
Please note than when specifying anything other than -ao alsa to MPlayer, you may lose DMIX support, so you won't be able to run two playbacks at the same time, and MPlayer would print:
[AO_ALSA] Unable to set hw-parameters: Device or resource busy
It is possible to fix that by using plain -ao alsa and specifying the the output device in $HOME/.asourdrc. Using the environment variable ALSA_CARD does work, but ALSA_PCM_DEVICE doesn't seem to work. Set up your $HOME/.asoundrc like this:
defaults.pcm.!card NVidia
defaults.ctl.!card NVidia
defaults.pcm.!device 0
defaults.ctl.!device 0
The device number 0 is analog output, 1 is S/PDIF and 3 is HDMI. The device numbers come from the output of aplay -l.

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