Hands-On

As expected, Vokoscreen proved to be uncomplicated in the lab. Recordings worked from the outset with the preset parameters, without interruptions or jitter. The image quality was satisfactory, and the file sizes were pleasingly compact.

The lack of a program icon in the system tray to control the software on some desktops did affect the ease of use, however: To record the desktop in such cases without the Vokoscreen window, you need to check the Vokoscreen minimized when recording starts option in the fourth tab and then control the minimized program with shortcut keys, where Ctrl+Shift+F11 is Stop and Ctrl+Shift+F12 is Pause. Vokoscreen still responds to these shortcuts with the window minimized.

I also noticed a problem while the program was running that was related to some versions of the libv4l library. This library, which is necessary for the correct use of webcams in Linux, does not support the RGB24 pixel format used by Vokoscreen in some variants, meaning that the webcam is not accessible. The webcam window in Vokoscreen opens, but remains black.

This problem manifested itself especially in three versions of Mageia 5. The operating system's obsolete Libv4l library failed to motivate the webcam to work on any of the three tested versions.

Krut

The fifth test candidate is something out of the ordinary: As a Java program, Krut is published under the GPL and thus a candidate for the review. You can pick up Krut as a ZIP archive from the project website [6], unpack the archive into any directory, and change to the newly created Krut subdirectory. All the program files are located there.

To call Krut, you need to have Java Runtime Environment 1.5 or higher in place on the operating system. In our lab, I had no trouble running Krut with the current Java Runtime Environment versions 1.7 and 1.8, regardless of whether you have the runtime environment from Oracle or the OpenJDK, as enabled by default on the latest Linux distributions when you install the operating system.

You can then launch the screencast program in a terminal by typing

java -jar krut-0.9.4.jar

A small window in the typical Java program design opens that has only three buttons: Menu, Rec, and Snap. With the help of the Snap and Rec buttons, you can create screenshots and screencasts, whereas clicking the Menu button opens a window with some basic settings (Figure 10).

Figure 10: The control window in Krut is very unobtrusive.

Options

To access the configuration menu, click on Menu | Settings/Save Files. Krut offers a variety of options for configuration, although they are not as detailed as in SimpleScreenRecorder or Vokoscreen. Therefore, everything fits in a single window (Figure 11). The software works well with the hardware detected by Linux.

Figure 11: Fully loaded: Krut offers all the settings in a single window.

Krut stores the video, audio, and screenshot files separately in their own subdirectories, so you specify a separate path for each type. In the settings window, you can also configure the frame rates for recording and playback separately and define whether you want mono or stereo recordings. Optionally, you can specify the bit depth of the recording, as well as the sampling frequency. A slider adjusts the encoding quality. Modified settings require confirmation in Krut and are applied when the window is closed.