Screencasts on Ubuntu

For a colleague I just made a screencast of a problem we were discussing. I was trying to use the minimum amount of tools in Gnome/Ubuntu and wanted to share the proces with you all.

Goal: Create a screencast recording of my desktop with narrated (recorded) audio at the same time.

If you are very curious and want to see the result immediately, look at the video below:

“Apache Kafka files store data without encryption”

I use Pop!_OS 21.04, which is based of Ubuntu. In Pop!_OS I use Gnome with Wayland.
All the instructions below will work with Ubuntu and any Ubuntu based distribution as well.

This howto is divided in several sections:

  • Desktop (Video) recording
  • Audio recording
  • Putting the video and audio recording together

Additional tools used in the video:

  • Show the webcam (guvcview)
  • Written annotation on a page (xournal++)
  • Written annotation on screen (Draw On You Screen)

Video recording:

Since I want to use the most simple method, my approach is to use the built-in screen cast ability in Gnome.

Press Ctrl+Alt+R to start the screen cast recording.

When the recording is in progress, you see a red filled circle in your notification area:

When you press Ctrl+Alt+R again, the circle disappears and the recording is saved to the Videos folder in your home folder:

Note: This video file is without audio.

Audio recording

As the most simple solution I used the builtin Sound Recorder in Gnome:

Press “Record” to start your recording and click “Done” when you would like to end your recording. You can see me pressing the buttons in the recorded screen cast.

Important: You need to press the screencast start keyboard command Ctrl+Alt+R and the Record button at the same time, or your video and audio will be out of sync.

When you stop the recording, the Ogg Vorbis file will be saved in the default location in your home folder, which is: ~/Recordings.

Combine the video and audio

Right now you have two separate files, not really useful when they are not combined.

To combine them, I used the following command:

ffmpeg -y -i Videos/Screencast\ from\ 05-12-2021\ 02:51:06\ PM.webm -i Recordings/Clip\ 5 -map 0:v -map 1:a -c copy file.webm

Explanation of the command:

ffmpeg
 this is the command itself
-y
 overwrite output files without asking
-i {file location}
 input file + file location
 Note that there are two input files (video & audio)
-map
 Designate one or more input streams as a source for the output file. The number is the first (0) or second (1) input file. The map itself shows what we are using in the output. In this case it is 0:v to use the video for the first input file and 1:a to use the audio of the second input file
-c copy file.webm
 Specify the output file, in this case it will be copied to file.webm in the same directory as where you run the command.

The result is what happens here:

GIF recording of putting the video and audio together (Recorded with Peek GIF Recorder)

This is the minimum necessary to create a screencast!

For example, you can send this webm video output file to people over email / file share / whatever you’d like. You can also upload it to Youtube, which can process the output file and you are done to spread some knowledge!

Add some extra spice to your screencast

To add some engagement with whoever will view your screencast, you can show your own webcam in the screen. You can use the built in program Cheese

Another option is to use guvcview, which has a cleaner interface (no buttons on the webcam output window)

Install with sudo apt install guvcview , start the program with guvcview.

Then select your video input device. You can minimize the settings pane so that you’re left with only the video of your webcam for the introduction/conclusion of your video.

Annotation

For annotation I use Xournalpp (xournal++) which helps me in drawing with my XP-Pen drawing tablet. I think it makes the screen cast a bit more entertaining compared to showing plain text but you can decide for yourself.

You can also use a Gnome Extension called Draw on You Screen by Abakkk, with this extension you can do annotations directly on the screen and thus show your thoughts / comments / pointers on screen directly.

Note: I don’t use this extension in my example video though.

Conclusion

I hope this blog post helps you in creating screen casts with the simplest possible tools. Good luck and hope to see your videos around on the web!

Update HP Proliant Microserver BIOS without Windows

I wanted to update my MicroServer Gen8 bios to the latest version but the download site on HPE only showed .EXE files. Since I’m only running Linux on my machines it was not possible to execute that file.

You can however update the BIOS via ILO (Integrated Lights Out) if you extract the BIOS file from the executable.

First download the .EXE from the HPE site: https://support.hpe.com/hpsc/swd/public/detail?swItemId=MTX_e9bfdf20809a426cb16ef9cd81

(Currently the latest version is SP99427.exe. If you want to be sure you’re using the latest BIOS then click the tab “Revision History” to see if there are newer BIOS files available)

Extract the contents of the executable. Have a look at the directory structure below and extract the file marked "CPQJ06xx.xxx"(where “x” might change depending on versions)

.
├── How to Use.txt
├── logo.gif
├── README.1ST
├── rev_hist.txt
├── ROMPaq Flat Files
│   ├── CPQJ0613.684
│   ├── CPQSRVR2.CPU
│   ├── README.1ST
│   ├── Readme.txt
│   └── ROMPAQ.EXE
├── ROMPaq USB Key
│   ├── CPQJ0613.684
│   ├── CPQSRVR2.CPU
│   ├── HPEUSB.exe
│   ├── Readme.txt
│   └── ROMPAQ.EXE
├── Start_files
│   ├── colorschememapping.xml
│   ├── filelist.xml
│   └── themedata.thmx
└── Start.htm
3 directories, 18 files

Then log in to ILO and navigate to the page “Firmware” via the Menu Option “Administrator”

At the bottom of the page select “Browse” to select the CPQJ06 file and then click Upload.

Let the upload complete and reboot your Microserver. When you start the microserver it displays the BIOS version and date in the first line.

You can also see the version in the ILO overview page.

Create a Java path entry for all users

I install Java on all my machines and used to add the java path and home variables to the user (or my user) bash profile but every time I added another user this is a manual step.

Until I found this small trick. Add a system wide profile path setting by creating a file in:

/etc/profile.d/filename

All files in profile.d are added to every users login. Much cleaner than adding it to every user’s profile.

This is the contents of my file:

/etc/profile.d/java-path.sh

export JAVA_HOME="/opt/java"
export PATH=$JAVA_HOME/bin:$PATH

These variables are set next time you log in with any user on that system.

Install Python without Admin rights (windows)

Appearently it’s quite simple to install python on a windows machine, even if you don’t have admin rights.

Remember, this only works if you downloaded the MSI installer version.

Open a command line in the same folder where you downloaded the python installer (Click here for the Python download page)

Execute this command on the CLI:

msiexec /a python-2.7.16.amd64.msi /qb TARGETDIR=C:\python27

Replace the version with your downloaded version

Use Skype with microphone in your Citrix Receiver session on Linux

Today I wanted to join a meeting but I was unable to be heard.
I’m connected to a Windows desktop via Citrix Receiver, I’m connecting from an Ubuntu Linux host.
Looking at the sound settings in my windows desktop, I saw that there was no recording device. So not being able to send sound makes sense then.
To enable input sound, add the following line to the WFClient section in your personal ICA settings file:
 
~/.ICAClient/wfclient.ini

[...]
[WFClient]
AllowAudioInput=True
[...]

Next, log off and log back into to your windows desktop and check the recording tab on the Sound settings, there a recording device now.
2018-08-31 08:20:43 screenshot
That should do the trick.

Weblogic LDAP backup (daily, and also very very simple)

My new colleague pointed me in the right way while I was scripting waaaaay too much to create a backup of the Weblogic users and groups.
The easiest way is to use the daily backup which is created by weblogic itself.
 
The backup is located on de adminserver, in this location:
$base_domain/servers/AdminServer/data/ldap/backup/EmbeddedLDAPBackup.zip
 
If there’s an issue with your embedded ldap, you can stop the adminserver, restore these files to this location:
$base_domain/servers/AdminServer/data/ldap/ldapfiles
Continue reading “Weblogic LDAP backup (daily, and also very very simple)”

FATAL Fatal error during KafkaServer startup, NumberFormatException

This might have taken me a long time to figure out, but fortunately my super awesome colleague (nicknamed Mr.T, he also pities fools) showed me the solution.
We ran into a Kafka Broker which was not starting, and gave the exception that is pasted in the bottom of this post.

FATAL Fatal error during KafkaServer startup. [..] java.lang.NumberFormatException

The solution is that the string (in this example “hs_err_pid19313”) is actually an error log which exists in a topic partition directory. (Re)move this file and Kafka will start without a problem.
(Tip: use find and grep to quickly find the file, go to your Kafka storage directory and run the following command;

find . |grep hs_err_pid19313

Continue reading “FATAL Fatal error during KafkaServer startup, NumberFormatException”

Citrix Receiver on Linux: SSL Error 61 ("You have not chosen to trust")

Important:
If you don’t know or understand certificates / root and intermediate certificate authorities, get someone who understands to follow below instructions.

I tried connecting to the company’s citrix server, but kept hitting the same error when I tried to open the connection:

Contact your help desk with the following information:
You have not chosen to trust "INSERT YOUR CA HERE",
the issuer of the server's security certificate (SSL Error 61)

It seems that Citrix has an alternate directory where it stores it’s trusted cert’s / certificate authorities. Even though you can see that the server’s certificate is trusted (by root CA’s) via a web browser, we need to copy those to the correct directory.
In short: Copy the root and intermediate CA’s to this directory: /opt/Citrix/ICAClient/keystore/cacerts
Continue reading “Citrix Receiver on Linux: SSL Error 61 ("You have not chosen to trust")”

Although GNOME Shell integration extension is running, native host connector is not detected

This is a bit of a nuisance, after a fresh install of Ubuntu Gnome, I was not able to install extensions from extensions.gnome.org.
Firefox asked me if I’d like to install the extension but after a Firefox restart I still wasn’t able to install any plugins.
To be precise; this message was shown:
Although GNOME Shell integration extension is running, native host connector is not detected. Refer documentation for instructions about installing connector.
The solution was to install the chrome-gnome-shell package;

sudo apt-get install chrome-gnome-shell

This fixes the message from both chrome and firefox.