Unable to play DVDs on Xubuntu or GStreamer backend error

Despite the fact that DVDs are a little bit old fashioned, I tried to watch one the other day. To my surprise I wasn’t able to do so. Every time I tried I got the following error

GStreamer backend error
Could not read DVD. This may be because the DVD is encrypted and a DVD decryption library is not installed.

But I already installed the library. I added the Medibuntu repository with the following command

sudo wget --output-document=/etc/apt/sources.list.d/medibuntu.list http://www.medibuntu.org/sources.list.d/$(lsb_release -cs).list && sudo apt-get --quiet update && sudo apt-get --yes --quiet --allow-unauthenticated install medibuntu-keyring && sudo apt-get --quiet update

and installed libdvdcss2

sudo apt-get install libdvdcss2 -y

But I still wasn’t able to watch the DVD. As it turned out, I need to set the region of the DVD drive. That’s pretty simply done with the tool regionset, which can be installed with your favorite package manager. Afterwards just execute the tool and set the region with the wizard.

regionset /dev/sr0

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Using nmap to find a Raspberry Pi within a network

I find it really annoying to connect an HDMI monitor and a keyboard to the Pi, in order to get the IP address to connect with SSH. The terminal program nmap is able to scan your network and gets the IP easily.

If nmap isn’t installed, install it with your favorite paket manager. On debian based systems you can use the following command:

sudo apt-get install nmap

Get your own ip with the following command.


In my case my address is This means that the Pi must be also within this range. The following command scans between and, but the maximum has to be entered as CIDR and in binary. The binary value of each section (max number is 255) is 11111111, in sum 24 x 1 and that is exactly what needs to be entered.


The result of the command depends on the network. In my case it looks like the following:

Nmap scan report for
Host is up (0.045s latency).
Not shown: 999 closed ports
22/tcp open ssh

After you got the IP, you can use ssh to get access to the PI with the username pi and the password raspberry

ssh pi@

I highly recommend to change the password after you successfully logged in for the first time.

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Step by step installation of Raspbian on a Raspberry Pi

First of all, download Raspbian. Check the website for the latest version. In my case I used wget to download the version:

wget wheezy-raspbian.zip

Get the checksum to check if the download was correct:

sha1sum 2014-09-09-wheezy-raspbian.zip

Unpack the zip archive:

unzip 2014-09-09-wheezy-raspbian.zip

Check all block devices with the following command, before you put the SD card into your PC:


Unmount the partition:

sudo umount /dev/

Copy the img file to the SD card – Be careful not to overwrite your HDD.

sudo dd if=2014-09-09-wheezy-raspbian.img of=/dev/ bs=4k

You’re finished. Put the SD card into the Pi and turn it on.

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Podcasts recommendations

I listen to podcasts nearly every day during my commute with my bicycle and I do love podcasts. Here is a short list of recommendations.

Stuff you should know
I know “Stuff you should know” for nearly one year now and it is definitely my favorite. Each episode is 30 min ish long, which makes is perfect for me and the topics are often interesting. The best thing is, however, that the hosts, Josh and Chuck, explain in a very funny and way. Sometimes I just want to listen to them, even if the topic is boring.

If you’re a .NET developer, you know Scott Hanselman. His podcast hanselminutes is often interesting. Scott is a .NET and C# developer by heart, but his podcasts isn’t focused on .NET only.

Chaosradio (German)
Chaosradio is the radio show of the Chaos Computer Club in Germany. The radio show started in 1996 and my first listen was back in 1998. Sometimes very technical, but every time interesting.

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Xubuntu, Code::Blocks and Ctrl+F9

Code::Blocks uses the Shortcut Ctrl + F9 to do a build. Unfortunately uses Xubuntu in its default settings Ctrl + F9 to switch to the workspace 9, if available. Xfce wins over Code::Blocks, which means Ctrl + F9 simply doesn’t work.

The solution is simple: Open Settings, go to Window Manager and clear the Workspace 9 shortcut.


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The problem with smartwatches

Smartwatches are a thing now, at least that what most of the tech news sites or the Apple Watch marketing department says. THEY must be right.

I own a smartwatch for nearly a year now. I bought a Pebble, because I think their concept is one of the best, even if it is one of the first and oldest ones. I love the display, because I am able to read it in every situation or condition, even in direct sunlight. The battery time is just awesome. Mine lasts for ten days.

I’m used to have a smartwatch and to get messages, calls or notifications directly to my watch. The vibration of the watch is key and it makes sure I don’t miss anything. My phone is in silent mode nowadays, because I don’t need the tones or the vibration anymore. Every notification is silent and only noticeable to me.

There is just one bad thing, that heads other people to the perception that I’m being impolite.

When I get a message I immediatly look at my watch, even if I talk to other people. People now tend to think that I need to go or that I don’t have enough time, sometimes they think that their topic isn’t that interesting to me or that I don’t care. People these days know that there are smart watches, but they barely have seen one. No one expects that I’m having one. No one knows that I’ve just looked what happened. If I would use my phone instead, people wouldn’t have a problem, because I guess that this is socially widely accepted, even that it is still kind of impolite, too.

So, I need to keep in mind not to look at my watch during a conversation or – more important – a meeting.

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Install node.js via npm

I recently wrote about the manual installation of Node.js. There is also the way via the npm Package manager:

First, install all dependencies:

sudo apt-get install python-software-properties python g++ make

Add a new ppa repository:

sudo add-apt-repository ppa:chris-lea/node.js 

Update all repositories

sudo apt-get update 

And finally install Node.js

sudo apt-get install nodejs
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