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<TITLE>CD, DVD, VCD - MPlayer - The Movie Player for Linux</TITLE>
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<H2><A NAME="drives">4.1 CD/DVD drives</A></H2>
<P>Linux documentation excerpt:</P>
<P>Modern CD-ROM drives can attain very high head speeds, yet some CD-ROM drives
are capable of running at reduced speeds. There are several reasons that might
make you consider changing the speed of a CD-ROM drive:</P>
<UL>
<LI>There have been reports of read errors at high speeds, especially
with badly pressed CD-ROMs. Reducing the speed can prevent data loss under
these circumstances.</LI>
<LI>Many CD-ROM drives are annoyingly loud, a lower speed may reduce the
noise.</LI>
</UL>
<P>You can reduce the speed of IDE CD-ROM drives with <CODE>hdparm</CODE> or a
program called <CODE>setcd</CODE>. It works like this:</P>
<P> <CODE>hdparm -E [speed] [cdrom device]</CODE></P>
<P> <CODE>setcd -x [speed] [cdrom device]</CODE></P>
<P>You can also try</P>
<P> <CODE>echo current_speed:4 > /proc/ide/[cdrom device]/settings</CODE></P>
<P>but you will need root privileges. The following command may also help:</P>
<P> <CODE>echo file_readahead:2000000 > /proc/ide/[cdrom device]/settings</CODE></P>
<P>This sets prefetched file reading to 2MB, which helps with scratched CD-ROMs.
If you set it to too high, the drive will continuously spin up and down, and
will dramatically decrease the performance.
It is recommended that you also tune your CD-ROM drive with
<CODE>hdparm</CODE>:</P>
<P> <CODE>hdparm -d1 -a8 -u1 (cdrom device)</CODE></P>
<P>This enables DMA access, read-ahead, and IRQ unmasking (read the
<CODE>hdparm</CODE> man page for a detailed explanation).</P>
<P>Please refer to "<CODE>/proc/ide/[cdrom device]/settings</CODE>" for
fine-tuning your CD-ROM.</P>
<P>SCSI drives do not have a uniform way of setting these parameters (Do you
know one? Tell us!) There is a tool that works for
<A HREF="http://das.ist.org/~georg/">Plextor SCSI drives</A>.</P>
<P>FreeBSD:</P>
<P> Speed: <CODE>cdcontrol [-f device] speed [speed]</CODE></P>
<P> DMA: <CODE>sysctl hw.ata.atapi_dma=1</CODE></P>
<H2><A NAME="dvd">4.2 DVD playback</A></H2>
<P>For the complete list of available options, please read the man page.</P>
<H4>New-style DVD support (mpdvdkit2)</H4>
<P>MPlayer uses <CODE>libdvdread</CODE> and <CODE>libdvdcss</CODE> for
DVD decryption and playback. These two libraries are contained in the
<CODE>libmpdvdkit2/</CODE> subdirectory of the MPlayer source tree, you
do not have to install them separately. We opted for this solution because
we had to fix a <CODE>libdvdread</CODE> bug and apply a patch which adds
<B>cracked CSS keys caching support</B> to <CODE>libdvdcss</CODE>. This results
in a large speed increase because the keys do not have to be cracked every time
before playing.</P>
<P>MPlayer can also use system-wide <CODE>libdvdread</CODE> and
<CODE>libdvdcss</CODE> libraries, but this solution is <B>not</B> recommended,
as it can result in bugs, library incompatibilities and slower speed.</P>
<H4>DVD Navigation support (dvdnav)</H4>
<P>Support for DVD navigation via <CODE>dvdnav</CODE> was being worked on, but
it was never finished properly and it is currently unmaintained. Who knows, it
might even compile.</P>
<H4>Old-style DVD support - OPTIONAL</H4>
<P>Useful if you want to play encoded VOBs from <B>hard disk</B>. Compile and
install <B>libcss</B> 0.0.1 (not newer) for this (If MPlayer fails to
detect it, use the <CODE>-csslib /path/to/libcss.so</CODE> option). To use it,
you need to be root, use a suid root MPlayer binary or let MPlayer call the
suid-root fibmap_mplayer wrapper program.</P>
<H4>DVD structure</H4>
<P>DVD disks have 2048 bytes per sector with ECC/CRC. They usually have an UDF
filesystem on a single track, containing various files (small .IFO and .BUK
files and big (1GB) .VOB files). They are real files and can be copied/played
from the mounted filesystem of an unencrypted DVD.</P>
<P>The .IFO files contain the movie navigation information (chapter/title/angle
map, language table, etc) and are needed to read and interpret the .VOB
content (movie). The .BUK files are backups of them. They use <B>sectors</B>
everywhere, so you need to use raw addressing of sectors of the disc to
implement DVD navigation or decrypt the content.</P>
<P>The whole old-style DVD support with <CODE>libcss</CODE> therefore needs a mounted DVD
filesystem and raw sector-based access to the device. Unfortunately you must
(under Linux) be root to get the sector address of a file. You have the
following choices:</P>
<UL>
<LI>Be root or use a suid-root mplayer binary.</LI>
<LI>Let MPlayer call the suid-root fibmap_mplayer wrapper program to access
the DVD (used in the old-style DVD playback over <CODE>libcss</CODE>).</LI>
<LI>Don't use the kernel's filesystem driver at all and reimplement it in
userspace. <CODE>libdvdread</CODE> 0.9.x and <CODE>libmpdvdkit</CODE> do this (new-style DVD
support). The kernel UDF filesystem driver is not needed as they already
have their own builtin UDF filesystem driver. Also the DVD does not have to
be mounted as only the raw sector-based access is used.</LI>
</UL>
<P>Sometimes <CODE>/dev/dvd</CODE> cannot be read by users, so the <CODE>libdvdread</CODE>
authors implemented an emulation layer which transfers sector addresses to
filenames+offsets, to emulate raw access on top of a mounted filesystem
or even on a hard disk.</P>
<P><CODE>libdvdread</CODE> even accepts the mountpoint instead of the device name for raw
access and checks <CODE>/proc/mounts</CODE> to get the device name. It was
developed for Solaris, where device names are dynamically allocated.</P>
<P>The default DVD device is <CODE>/dev/dvd</CODE>. If your setup differs,
make a symlink, or specify the correct device on the command line with the
<CODE>-dvd-device</CODE> option.</P>
<H4>DVD authentication</H4>
<P>The authentication and decryption method of the new-style DVD support is done
using a patched <CODE>libdvdcss</CODE> (see above). The method can be specified through the
environment variable <CODE>DVDCSS_METHOD</CODE>, which can be set to
<CODE>key</CODE>, <CODE>disk</CODE> or <CODE>title</CODE>.</P>
<P>If nothing is specified it tries the following methods
(default: key, title request):</P>
<OL>
<LI><B>bus key:</B> This key is negotiated during authentication (a long mix
of ioctls and various key exchanges, crypto stuff) and is used to encrypt
the title and disk keys before sending them over the unprotected bus
(to prevent eavesdropping). The bus key is needed to get and predecrypt the
crypted disk key.</LI>
<LI><B>cached key:</B> MPlayer looks for already cracked
title keys which are stored in the <CODE>~/.mplayer/DVDKeys</CODE> directory
(fast ;).</LI>
<LI><B>key:</B> If no cached key is available, MPlayer tries to
decrypt the disk key with a set of included player keys.</LI>
<LI><B>disk:</B> If the key method fails (e.g. no included player keys),
MPlayer will crack the disk key using a brute force algorithm.
This process is CPU intensive and requires 64 MB of memory (16M 32Bit
entries hash table) to store temporary data. This method should always
work (slow).</LI>
<LI><B>title request:</B> With the disk key MPlayer requests the crypted title
keys, which are inside <I>hidden sectors</I> using <CODE>ioctl()</CODE>.
The region protection of RPC-2 drives is performed in this step and may
fail on such drives. If it succeeds, the title keys will be decrypted with
the bus and disk key.</LI>
<LI><B>title:</B> This method is used if the title request failed and does
not rely on any key exchange with the DVD drive. It uses a crypto attack to
guess the title key directly (by finding a repeating pattern in the
decrypted VOB content and guessing that the plain text corresponding to the
first encrypted bytes is a continuation of that pattern).
The method is also known as "known plaintext attack" or "DeCSSPlus".
In rare cases this may fail because there is not enough encrypted data on
the disk to perform a statistical attack or because the key changes in the
middle of a title. This method is the only way to decrypt a DVD stored on a
hard disk or a DVD with the wrong region on an RPC2 drive (slow).</LI>
</OL>
<P>RPC-1 DVD drives only protect region settings through software.
RPC-2 drives have a hardware protection that allows 5 changes only. It might
be needed/recommended to upgrade the firmware to RPC-1 if you have a RPC-2 DVD
drive. Firmware upgrades can be found on this
<A HREF="http://www.firmware-flash.com">firmware page</A>. If there is
no firmware upgrade available for your device, use the
<A HREF="http://www.linuxtv.org/download/dvd/dvd_disc_20000215.tar.gz">regionset
tool</A> to set the region code of your DVD drive (under Linux).
<B>Warning:</B> You can only set the region 5 times.</P>
<H2><A NAME="vcd">4.3 VCD playback</A></H2>
<P>For the complete list of available options, please read the man page.
The Syntax for a standard Video CD (VCD) is as follows:</P>
<P><CODE>mplayer -vcd <track> [-cdrom-device <device>]</CODE></P>
<P>Example: <CODE>mplayer -vcd 2 -cdrom-device /dev/hdc</CODE></P>
<P>The default VCD device is <CODE>/dev/cdrom</CODE>. If your setup differs,
make a symlink or specify the correct device on the command line with the
<CODE>-cdrom-device</CODE> option.</P>
<P><B>Note:</B> At least Plextor and some Toshiba SCSI CD-ROM drives have
horrible performance reading VCDs. This is because the the CDROMREADRAW ioctl
is not fully implemented for these drives. If you have some knowledge of SCSI
programming, please <A HREF="tech/patches.txt">help us</A> implement generic
SCSI support for VCDs.</P>
<H4>VCD structure</H4>
<P>VCD disks consist of one or more tracks:</P>
<UL>
<LI>The first track is a small 2048 bytes/sector data track with an iso9660
filesystem, usually containing Windows VCD player programs and maybe other
information (images, text, etc).</LI>
<LI>The second and other tracks are raw 2324 bytes/sector MPEG (movie) tracks,
containing one MPEG PS data packet per sector instead of a filesystem.
Similar to audio CD tracks, these tracks <B>cannot be mounted</B> (Did you
ever mount an audio CD to play it?). As most movies are inside this track,
you should try <CODE>-vcd 2</CODE> first.</LI>
<LI>There exist VCD disks without the first track (single track and no
filesystem at all). They are still playable, but cannot be mounted.</LI>
</UL>
<H4>About .DAT files:</H4>
<P>The ~600 MB file visible on the first track of the mounted VCD is not a real
file! It is a so called ISO gateway, created to allow Windows to handle such
tracks (Windows does not allow raw device access to applications at all).
Under Linux you cannot copy or play such files (they contain garbage). Under
Windows it is possible as its iso9660 driver emulates the raw reading of
tracks in this file. To play a .DAT file you need the kernel driver which can
be found in the Linux version of PowerDVD. It has a modified iso9660
filesystem (<CODE>vcdfs/isofs-2.4.X.o</CODE>) driver, which is able to emulate
the raw tracks through this shadow .DAT file. If you mount the disc using
their driver, you can copy and even play .DAT files with mplayer. But it
<B>will not work</B> with the standard iso9660 driver of the Linux kernel!
Use the <CODE>-vcd</CODE> option instead. Alternatives for VCD copying are
the new <A HREF="http://www.elis.rug.ac.be/~ronsse/cdfs/">cdfs</A> kernel
driver (not part of the official kernel) that shows CD <I>sessions</I>
as image files and <A HREF="http://cdrdao.sourceforge.net/">cdrdao</A>, a
bit-by-bit CD grabbing/copying application.</P>
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