Konverter is an easy to use but powerful KDE frontend for MEncoder. It helps to convert almost any video file into the most common different video formats and codecs. Beside conversion, it is able to scale and crop videos, change codec details, or just change the audio / video format of files.
Wagtail is a client/server-based tool for audio encoding. It is designed to make it easier to encode and organize files in bulk. Wagtail allows you to enforce standards across your media collection with the use of "formats", each describing an audio format, how to encode/tag, etc. It also uses "classes", a combintation of formats and quality settings, as well as "tasks", which set the naming conventions, file locations, and reprocessing stages for files, and restricts which classes can be used. It includes wagdisc for ripping CDs and wagfile for processing files.