How to create a screencast on your linux desktop

Screen casting is the act of recording your desktop while you do something, for example, running an application, replicating a test-case scenario or creating a training video, etc. Optionally you may or may not want your voice being recorded along with the video. Whilst there are many free and popular tools available for Windows to do such a task, in the Linux world the de-facto standard is a nifty little program called recordMyDesktop. Apart from a command line interface, it also has a very simple but elegant GUI that lets you easily create a screencast with audio recording enabled, while also providing you the option to specify some advanced settings such as screen co-ordinates (the area on your desktop you want recorded), audio/video input devices and the number of channels:

recordMyDesktop

The above image shows recordMyDesktop program running on my Ubuntu 12.04 Linux distro. All you have to do is set the video quality and optionally set the sound quality if you also need voice recording. Most of the time, there is no need to open Advanced Settings. A few scenarios I can think of is where you want to specify an explicit FPS (Frames per second) value, apart from the default which is 15. Or else, you want to specify an explicit screen resolution.

There is also a feature that enables you to record a single window instead of the entire desktop. Just use the select “window button” on bottom left corner to do so.

Once the recording is done, the program encodes the video in .ogv (Ogg Vorbis) format as saves in your home folder with the filename, “out-n.ogv”. Ogg Vorbis is a pretty standard video format most modern programs are able to play.

Installing this program on your linux desktop is pretty easy. Depending on your package management system, this is usually done by issuing a single command in your terminal:

sudo apt-get install recordMyDesktop

This is for apt-based distros such as Debian and Ubuntu. On Fedora you may use yum, or zypper on openSUSE.

How to add or remove launchers from your gnome classic/fallback desktop panel

This is a nice little hack that comes handy when you want to add or remove launchers (shortcuts to your favorite programs such as firefox or gedit) to an existing panel, or add an entirely new panel to your gnome-classic or fallback desktop. On my Linux Mint workstation, I prefer the gnome-classic version instead of the default cinnammon desktop for reasons of speed and simplicity. I soon found out, however, that process of adding/removing launchers or adding a new panel requires a special key combination that is not easily found without going through some extensive documentation!! Here is how you do it:

To add a new launcher:

1. Press the WIN (Super) and ALT keys together.
2. While keeping them pressed, right-click the panel.
3. You will then get a popup menu saying “New Panel”, or “Add to Panel”.
4. Click on the second option and select your program.

To edit/remove an existing launcher:

1. Follow steps 1 & 2 from above.
2. You will get a popup menu saying “Move” and “Remove from Panel”.
3. Click on your choice.

How to make brightness changes permanent in your Linux Desktop?

Quite recently, I’ve faced this nagging little issue on all the distros I tried. These included Ubuntu 12.04 LTS, Linux Mint 11.1 and Fedora 18. Whenever I changed my computer’s brightness setting either through the gnome-settings applet or by using hotkeys, the changes were only temporary. On next reboot, they would vanish!! Now what is the easiest way to make your chosen setting permanent? After much googling and head-scratching, I finally arrived at the answer.

First of all, NEVER place anything like this in a startup script:

echo 4 > /sys/class/backlight/acpi_video0/brightness

(See this update if you found this folder empty or missing)

Although this command might change your brightness, again the effects are only temporary and will be lost on your next reboot. If you attempt to place this in /etc/rc.local, it may not always work due to permission issues. Instead of ending up chmod-ing the permissions to the brightness file and cause any other issues in turn, the recommended approach is to use xbacklight, the tool fit for this purpose.

Here is the easy way:

1. Install xbacklight from your package repository. On Linux Mint, I did this:

sudo apt-get install xbacklight

2. Place xbacklight command with your chosen settings in your “startup-applications” applet. In my case I had the command: xbacklight -set 50

On Mint Linux, it looked something like this:

Image for xbacklight-startup
Configure xbacklight in startup-applications applet

Thats all. This effectively sets brightness to 50% by default upon your each login. Enjoy!!

UPDATE on 04-mar-2013: I came to know today that the 3.4 kernel has broken some things related to acpi-support for setting brightness. As a result of that the /sys/class/backlight folder is empty and the xbacklight program also won't work!! Solution? Either upgrade/downgrade your kernel or add "acpi_backlight=vendor" to your menu.lst. See this link for more information:

http://superuser.com/questions/548459/how-to-change-screen-brightness-on-toshiba-satellite-l850-djs-in-linux/556745#comment683067_556745