OBS, or Open BroadcasterSoftware, is a free (and open source) screen recorder that also supports livestreams and facecams.
Ranked in these QuestionsQuestion Ranking
Pro Records to many popular formats
You can record videos in formats such as mp4, flv, mkv, and more. You also have control over the bitrate used.
Pro Free and open source
No subscriptions or payments or licenses.
Pro Available for Linux, Mac, Windows
From the website: "GPU-based game capture for high performance game streaming."
OBS has an API allowing developers to create their own unique plugins, giving them and others complete control of their streaming experience.
Pro Unlimited number of scenes and sources
Pro Encoding using H264 (x264) and AAC and file output to MP4 or FLV
Con Overkill for simple projects
Plus the interface is a bit intimidating.
Con Recording a window will not record the menu bar, popup menus or child dialogs
Con Needs tutorial to get started
Otherwise it's hard to find out how to record a screen or window.