The following should work.
mplayer -afm hwac3,hwdts, -ao alsa:device=hdmi -channels 2
file
or
mplayer -afm hwac3,hwdts, -ao alsa:device=plughw:0.2 -channels 2
file
Digital audio is not reliable in Linux. Linux is not designed for computer illiterates. Also Linux is still design for servers. Third Linux power saving features like Suspend to RAM or Suspend to Disk is not reliable enough to use in production systems.
A notebook computer that I suggest for computer illiterates is a MacBook or MacBook Pro. Mac OS X has Unix like commands that can be access from Applications -> Utilities -> Terminal.
If you insist using Linux for notebook computers, you have to do the following.
1) Install MPlayer with almost every feature do not forget LIVE support and leave out GUI or GTK
2) Install SMPlayer
3) Install mplayerplug-in
4) Install VLC
5) Install Adobe Flash plug-in
6) Install Adobe Reader
7) Install PulseAudio and its utilities and modules
8) Pick a GUI WiFi program that is easy. I use kwifimanager.
9) Install acpid, cpufreqd, and laptop-tools
10) Install hibernate scripts and configure
11) Configure acpid, cpufreqd, and laptop-tools
12) Configure hal and dbus for removable storage devices
13) Install and configure ifplugd
14) Configure PulseAudio
15) Test mplayerplug-in at apple.com, nasa.gov, or others
16) Test WiFi
17) Test removable storage
18) Test power management between AC and battery
19) Test hibernate scripts for Suspend to RAM or Suspend to Disk
20) Test lid close if want to turn off lamp.
21) Test xscreensaver or similar program
22) Test PulseAudio to find out how easy it is to switch from analog outputs to digital
The following is what I use for MPlayer config (/etc/mplayer/mplayer.conf).
Code:
##################
# video settings #
##################
# Specify default video driver (see -vo help for a list).
vo=vdpau,gl,xv,x11,null
dr=yes
##################
# audio settings #
##################
# Specify default audio driver (see -ao help for a list).
ao=alsa,oss,null
##################
# other settings #
##################
# Drop frames to preserve audio/video sync.
framedrop = yes
# cache settings
cache = 102400
# Prefill 20% of the cache before starting playback.
cache-min = 20.0
# Prefill 50% of the cache before restarting playback after the cache emptied.
cache-seek-min = 20
# DVD: Display English subtitles if available.
#slang = en
# DVD: Play English audio tracks if available.
alang = en
# You can also include other configuration files.
#include = /path/to/the/file/you/want/to/include
fontconfig=1
subfont-osd-scale=4
subfont-text-scale=3
a52drc=0
identify=yes
stop-xscreensaver=yes
xineramascreen=-1
lavdopts=threads=2
[vo.gl]
vf-clr=yes
vf=softskip,scale=-1:-1
[vo.vdpau]
vf-clr=yes
#For VDPAU to work properly
vc=ffmpeg12vdpau,ffwmv3vdpau,ffvc1vdpau,ffh264vdpau,
I suggest use Gentoo for better flexibility during setup.