GNOME 3 has inbuilt application to create an screencasting. Screencasting can been easily done with the help of few shortcut keys. This is the most easiest way for Screencasting which doesn’t involve any other application. You can simply start screencasting with hotkeys ctrl+Alt+shift+R. The recording begins with the red spot appear in button of your screen. The moment you press the hot key the recording of your screen will begin. The same key is used to stop recording the screencasting. When you stop recording the file will be saved in your home directory. The file format of your recorded video will be like this shell-20111027-1.webm
The WebM file structure is based on Matroska media converter the VP8 video code and vorbis audo codec is used to compressed video and audio respectively. The file name will be shell followed by date that is %d and each unique string %u followed by the file extension.
Another great stuff about default GNOME 3 screenscasting is that most of the online video sharing website support the WeBM file format. Therefore you don’t have to to be panic changing one file format to another . Another great advantage of default screencasting in GNOME 3 is that you can preview your recording video in the phase of recording meaning as soon as you start recording your video will be save on home folder and you can preview the recording by opening the video while you are on recording phase.