Problems with playing DVD

29 respostas [Última entrada]
GNUbahn
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Joined: 02/19/2016

I often encounter problems when trying to play a DVD on my Trisquel (and earlier other distributions) computers. Everywhere I read, that this or that player will play virtually everything. So how come I still have problems?

Is there something I can do, or do I just have to realise, that 'virtually everything' means many but far from all?

jxself
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Joined: 09/13/2010

Who knows? There isn't much detail to go on here other than you've got problems.

GNUbahn
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Joined: 02/19/2016

Nice comment - point taken :-)

Again I reveal my lack of knowledge (that'll probably happen again soon!).

It takes knowledge to describe a problem well.

loldier
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Joined: 02/17/2016
GNUbahn
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Joined: 02/19/2016

And it always has been! But is it good or bad luck, that I am not too dumb to know I am?

Stupido, ergo sum

Thanks for the links. I'm beginning to learn

Magic Banana

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Joined: 07/24/2010

Have you installed libdvdcss2? From the terminal:
$ sudo /usr/share/doc/libdvdread4/install-css.sh

SuperTramp83

I am a translator!

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Joined: 10/31/2014

Yeah, I can confirm what mr Banana is saying, that package is required for encrypted DVDs to play (I assume OP is talking about this)

GNUbahn
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Joined: 02/19/2016

command not found

yet libdvdread4 is already the newest version (5.0.3-1).

and ls -l gives
/usr/share/doc/libdvdread4$ ls -l
totalt 20
-rw-r--r-- 1 root root 1176 jan 2 2014 AUTHORS
-rw-r--r-- 1 root root 1479 okt 24 2015 changelog.Debian.gz
-rw-r--r-- 1 root root 1302 aug 30 2014 copyright
-rw-r--r-- 1 755 root 2648 nov 6 2013 README
-rw-r--r-- 1 755 root 754 aug 30 2014 README.css

Does this mean, I have to follow these:
https://wiki.debian.org/CDDVD#Video_DVD

or are there other (read: easier) solutions?

loldier
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Joined: 02/17/2016

Libdvdread is only a menu library to read unencrypted file structures on a DVD. You'll need libdvdcss. It's not available in any repositories. You'll have to download it from Videolan.

http://download.videolan.org/debian/

Magic Banana

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Joined: 07/24/2010

Are you on Trisquel 8? "libdvdread4" on Trisquel 7 only is at version 4.2.1-2ubuntu1 and it contains the script. I guess you can just download that script (attached to this post) and execute it.

AnexoTamaño
install-css.sh 3.36 KB
onpon4
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Joined: 05/30/2012

I feel pretty sure that script just doesn't work anymore. You need to install libdvdcss the other way.

Magic Banana

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Joined: 07/24/2010

It works on Trisquel 7 at least. And nothing in the script seems to be specific to Trisquel 7 or to Ubuntu 14.04.

loldier
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Joined: 02/17/2016

Magic Banana's attachment throws an error:

"You don't have permission to access /files/install-css.sh
on this server."

I think executable files are not permitted as attachments unless they are buried in an archive.

Magic Banana

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Joined: 07/24/2010

Let us try with GZIP.

AnexoTamaño
install-css.sh.gz 1.4 KB
loldier
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Joined: 02/17/2016

The archive works (extracts) alright.

# Shell script to install libdvdcss under Debian GNU Linux
# Many DVDs use css for encryption. To play these discs, a special library
# is needed to decode them, libdvdcss. Due to legal problems, Debian and most
# Linux distibutions cannot distribute libdvdcss
# Use this shell script to install the libdvdcss under DEBIAN GNU/Linux

GNUbahn
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Joined: 02/19/2016

How do I run it?

When running
sudo: ./install-css.sh

inside the folder in which I extracted the file, I get

sudo: ./install-css.sh: command not found

Should I extract it in a specific folder or is there another command I have to use?

Anonymous (non verificado)
Anonymous

Try this: chmod +x ./install-css.sh

Sasaki
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Joined: 08/11/2014

And to install it ;-)

copy the full name of your package, open a terminal in the place you have downloaded it (for example : cd ~/Downloads, or simply right click in an empty space in the files manager)

then type

sudo dpkg -i PASTE HERE THE NAME OF YOUR PACKAGE

and you're done.

Next time you experience problems, check here

https://trisquel.info/en/wiki/media

and here

https://help.ubuntu.com/community/CommunityHelpWiki

SuperTramp83

I am a translator!

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Joined: 10/31/2014

Download the tar, extract it and compile it. Read the INSTALL text file.

https://download.videolan.org/pub/libdvdcss/1.4.0/

GNUbahn
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Joined: 02/19/2016

I donwloaded the libdvdcss2_1.2.13-0_amd64.deb from https://download.videolan.org/debian/stable/ and gave it a sudo dpkg -i It installed perfectly, i.e. I now have a /usr/share/doc/libdvdcss2 folder.

I also extracted the install-css.sh into /usr/share/doc/libdvdread4

Yet I get:

jb@jb-x200:/usr/share/doc/libdvdread4$ ls
AUTHORS changelog.Debian.gz copyright install-css.sh README README.css
jb@jb-x200:/usr/share/doc/libdvdread4$ sudo ./install-css.sh
sudo: ./install-css.sh: Kommando ikke fundet [=command not found]
jb@jb-x200:/usr/share/doc/libdvdread4$

What am I doing wrong?

loldier
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Joined: 02/17/2016

Try this

sh install-css.sh

GNUbahn
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Joined: 02/19/2016

That worked.

Thanks. But why did that work and ./install-css.sh did not?

loldier
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Joined: 02/17/2016
GNUbahn
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Joined: 02/19/2016

If I got it right, any executable outside the /bin/sh folder has to be defined an executable (e.g. by chmod +x script.sh) or by using the sh command (because in this case it is a script).

Is that (about) right?

Magic Banana

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Joined: 07/24/2010

You are. However the 'sh' command calls a specific interpreter (/bin/sh). When you directly execute an executable file (e.g., made executable with 'chmod +x'), the interpreter is chosen according to the line starting with "#!" at the beginning of the script; or the shell if there is no such line (and no interpreter if the file is an executable binary). For instance, those "#!" lines (in the output of grep '^#!' /usr/bin/* on my system) launch different interpreters for different programming languages (or with different options for the same language):
#!/bin/bash
#!/bin/sed -f
#!/usr/bin/awk -f
#!/usr/bin/perl -w
#!/usr/bin/python
#!/usr/bin/python -OOt
#!/usr/bin/python3
If you precede those scripts with 'sh', they would not execute properly because they are not written in the Shell programming language (well, GNU Bash is an extension of the Bourne Shell programming language, so it will probably not entirely execute properly).

GNUbahn
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Joined: 02/19/2016

I am getting closer, but I still get this:

jb@jb-x200:~$ sudo /usr/share/doc/libdvdread4/install-css.sh
[sudo] adgangskode for jb:
sudo: /usr/share/doc/libdvdread4/install-css.sh: Kommando ikke fundet
jb@jb-x200:~$

GNUbahn
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Joined: 02/19/2016

Can I check via terminal, if css is active?

loldier
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Joined: 02/17/2016

It doesn't make much sense. I think you're safe to ignore the script once you've used it to download the library.

You either have the library (libdvdcss) on your computer or not. Insert a protected disc, fire up a player like VLC, and if the player can find the library, it will be able to unscramble almost any encrypted DVD you throw at it.

About libdvdcss:

Non-technical description of libdvdcss (v2.1)

libdvdcss is a library that computer programs can use to access the
contents of a DVD.

1/ DVD zones

All DVDs and commercially distributed readers include some information
about their zone. When a DVD is put into a DVD reader, the information is
compared, in order to limit the number of countries where the DVD can be
used. The DVD zone and the reader's zone should match.

2/ CSS

CSS (Content Scrambling System) protects most commercial DVDs. Writers
of DVD reader programs obtain keys by purchasing them from the DVD CCA (DVD
Copy Control Association) which will permit them to decrypt CSS-protected
DVDs. They also get instructions on how to use CSS, which are kept secret
under a confidentiality agreement. When a program reads a DVD, it
communicates with the DVD reader all the time, in order to get the
decryption information with the help of the key.

3/ Copying DVDs

The present systems do not prevent the copying of DVDs. With the right
equipment, a perfect physical copy of the media can be made (often called a
'bit by bit') which will be possible to exploit in the same way.
Furthermore, since the media must be decrypted by the reading program in
order to appear on the screen, the decrypted content of the media will be
accessible while it is being viewed - whatever the equipment used.

4/ Weaknesses of CSS

CSS has been the subject of academic studies which have, through reverse
engineering, uncovered how it works and what encryption algorithm it uses.
These studies also show that the keys used by CSS are extremely weak from a
cryptographic (code-breaking) perspective, which has led to more effective
decryption algorithms and the discovery of keys. It is possible to obtain
a complete list of keys in a few minutes on an ordinary desktop computer.

5/ How libdvdcss works

The list of CSS keys is therefore perfectly well known, and a sample of
these keys is distributed with libdvdcss. The libdvdcss library operates
in a similar manner to a DVD reader program, by using a key to decode the
content, except that libdvdcss uses a key from the sample. If all of the
sample keys fail, then libdvdcss computes the rest of the key set and tries
each of them.

This might still not work, particularly if the DVD and the reader are
not from the same zone. As a last resort, libdvdcss will step outside of
the whole DVD/reader system and will decrypt the encoded stream directly,
exploiting weaknesses in the CSS encryption.

http://www.videolan.org/developers/libdvdcss.txt

GNUbahn
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Joined: 02/19/2016

Thanks - sometimes finding the right place to read is the biggest issue!

SuperTramp83

I am a translator!

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Joined: 10/31/2014

also, be aware that installing the libdvdcss package in the Saudi Arabia of North America is illegal. But then again breaking unjust laws is just.