Playing standard Video CDs:

mplayer -vcd trackno [-cdrom-device device]

Examples:
mplayer -vcd 1
mplayer -fs -vcd 2 -cdrom-device /dev/hdc

Notes:
- Do NOT mount VCD disks and play DAT files directly! It may work under windows but won't work under linux. You have to play them directly, with the -vcd option!
- VCD disks usually have 2 tracks: a data track (containing autostart windows playback program, karaoke data etc) and a mode-2 track (the movie), so try -vcd 2 first!
- the default VCD device is /dev/cdrom. if your device differs, then you have to make a symlink, or specify it in command line!

From Linux documentation:

Some CDROM drives are capable of changing their head-speed. There are several reasons for changing the speed of a CDROM drive. Badly pressed CDROMs may benefit from less-than-maximum head rate. Modern CDROM drives can obtain very high head rates (up to 24-times is common). It has been reported that these drives can make reading errors at these high speeds, reducing the speed can prevent data loss in these circumstances. Finally, some of these drives can make an annoyingly loud noise, which a lower speed may reduce.

The recommended way to do it is with a program called 'setcd' . It's kinda old, but won't be too hard to find on the Net. (UPDATE : new hdparm has an option for this !) Use it with :

setcd -x [speed] [cdrom device]

Also you can try:

echo current_speed:4 >/proc/ide/[cdrom device]/settings

but you'll need root privileges. I use following command too:

echo file_readahead:2000000 >/proc/ide/[cdrom device]/settings

for 2MB prefetched reading from the file (it's useful for scratched CDROMs). It's recommended that you tuneup your CDROM drive also with hdparm:

hdparm -d1 -a8 -u1 (cdrom device)

to enable using DMA access, readahead, and IRQ unmasking. (if you don't understand these, *read the hdparm man page*)

Please refer to "/proc/ide/[cdrom device]/settings" for fine-tuning your CDROM.

4.2. DVD playback

MPlayer uses libdvdread and libdvdcss for DVD decryption and playing. These two libraries are contained in the libmpdvdkit/ subdirectory in the MPlayer tree, you don't have to install them separately. We opt for this solution because we had to fix a libdvdread bug, and apply a patch which adds cracked CSS keys caching support for libdvdcss (results in large speed increase before playing). These cracked keys are stored in $HOME/.mplayer/DVDKeys directory.

Support for dvdnav is being added (not usable now).

Old-style DVD support - OPTIONAL

Useful if you want to play encoded VOB's from hard disk. Compile and install libcss 0.0.1 (not newer) (if MPlayer can't detect it, use the -csslib /path/to/libcss.so option).

Compile MPlayer.

Run ./configure. If you didn't delete libmpdvdkit subdirectory from MPlayer tree, ./configure should say the following:

Checking for DVD support (libmpdvdkit) ... yes

(of course you can put your favourite configure options into the command line when you run ./configure)

MPlayer can use libdvdread and libdvdcss libraries installed system-wide, but this solution is NOT RECOMMENDED, as can result in bugs, library incompatibilities, and slower speed.

Either way, say: make, then make install.

Using MPlayer to play DVDs:

-dvd <title_id>	Enables DVD support and selects title.
-chapter <chapter_id>	Selects DVD chapter(s) to play (default: play from chapter 1). Example : `-chapter 5-10` or `-chapter -9`
-dvdangle <angle_id>	Selects camera angle (default: 1)
-alang <country code>	The `country code` tells MPlayer which audio language(s) to prefer. For the list of available languages, add `-v` option after your DVD options, and browse the output. For example : `-alang hu,en` - first tries to find hungarian audio, and if not found, decode english audio.
-slang <country code>	Turns on DVD subtitles. The `country code` tells MPlayer which language(s) to prefer. For the list of available languages, add `-v` option after your DVD options, and browse the output. For example : `-slang hu,en` - first tries to display hungarian subtitles, and if not found, display english subtitles.
-sid <subtitle_id>	Displays a subtitle channel with the given `id` (values can be 0-31). Useful for example with badly mastered DVDs where country code selects the wrong channel.
-csslib <path/filename>	(old-style DVD option) This option is used to override the default location of `libcss.so`
-dvdauth <DVD device>	(old-style DVD option) Turns on DVD authentication using the given device.
-dvdkey <CSS key>	(old-style DVD option) When decoding from non-DVD, this option gives the CSS key needed to crack the DVD (the key is printed when authenticating with DVD).

Default device is /dev/dvd, you can change it in config.h (compile time option), or you can specify it using the -dvd-device option :

mplayer -dvd 1 -dvd-device /dev/dvd

mplayer -dvd 1 -slang en -dvd-device /dev/dvd

mplayer -dvd 1 -slang en -dvd-device /dev/dvd -chapter 20-25

mplayer -dvd 2 -alang sp -chapter 5 -dvdangle 2

mplayer -dvdauth /dev/dvd /mnt/cd/video_ts/vts_03_1.vob

mplayer -dvdkey C005D4A16D vts_03_1.vob