Among a bunch of funny features Gnome 3 come with a nice default embedded screen recorder. This screen recorder is very handy but it has a major defect (in my point of view): the default maximum length of a screencast is 30 seconds. It's not difficult to understand that with a such lower value the screen recorder is just unusable!
In the previous versions of Gnome 3, this value was hard coded, then the change of this value was difficult and non mantainable.
Since gnome 3.10 the maximum lenght of a screencast is leveraged by the gconf registry. So you can now override the default value in a very simple manner.
Hereunder I'll show you two ways to edit the maximum length property:
dconf-editorin a terminal;
org->gnome->settings-daemon->plugins->media-keysand set the value of the property
max-screencast-lengthby double-clicking on the actual value (30)
Open a terminal and type:
gsettings set org.gnome.settings-daemon.plugins.media-keys max-screencast-length 45
This command set the value of screen maximum length screencast to 45 seconds.