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Remove technical description of DVDs and libdvdread implementation. 

It is out of place in the user-level documentation and there are
more exhaustive sources elsewhere.


git-svn-id: svn://svn.mplayerhq.hu/mplayer/trunk@24344 b3059339-0415-0410-9bf9-f77b7e298cf2
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diego 2007-09-05 12:56:23 +00:00
parent b13b7a54c2
commit 74e2767527
1 changed files with 0 additions and 44 deletions
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44
DOCS/xml/en/cd-dvd.xml
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@ -141,50 +141,6 @@ In case of DVD decoding problems, try disabling supermount, or any other such
facilities. Some RPC-2 drives may also require setting the region code.
</para></note>
<formalpara>
<title>DVD structure</title>
<para>
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 .BUP
files and big (1GB) .VOB files). They are real files and can be copied/played
from the mounted filesystem of an unencrypted DVD.
</para>
</formalpara>
<para>
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 .BUP files are backups of them. They use
<emphasis role="bold">sectors</emphasis> everywhere, so you need to use raw
addressing of sectors of the disc to implement DVD navigation or decrypt the
content.
</para>
<para>
DVD support needs raw sector-based access to the device. Unfortunately you must
(under Linux) be root to get the sector address of a file. That's why we don't
use the kernel's filesystem driver at all, instead we reimplement it in
userspace. <systemitem>libdvdread</systemitem> 0.9.x does this.
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.
</para>
<para>
Sometimes <filename>/dev/dvd</filename> cannot be read by users, so the
<systemitem>libdvdread</systemitem> 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.
</para>
<para>
<systemitem>libdvdread</systemitem> even accepts the mountpoint instead of
the device name for raw access and checks <filename>/proc/mounts</filename>
to get the device name. It was developed for Solaris, where device names
are dynamically allocated.
</para>
<formalpara>
<title>DVD decryption</title>
<para>