MakeMKV is a one-click solution to convert video from DVD or Blu-ray discs into MKV, which is a free and patent-unencumbered format that can be played everywhere. MakeMKV is a format converter or "transcoder". The only thing it does is convert video clips from a (usually encrypted) disc into a set of MKV files, preserving most information but not changing it in any way. The MKV format can store multiple video and audio tracks with all meta-information and preserve chapters.
AstroAviBrowser is a small tool for astronomy imaging capture/processing. It allows you to open a video file, select the good frames, and save the new sequence in a new avi file using raw or lossless codecs. You may also de-bayer your frames and separate RGB plans. It's a kind of "AviRaw" for Linux.
Arista is an easy-to-use multimedia transcoder for the GNOME desktop. It focuses on the goal of transcoding media, namely the devices you wish to play the media on. It is designed for use by people who are not familiar with audio and video encoding and want an easy way to get multimedia to their devices. It supports input from DVD and V4L devices as well as regular files.