Avidemux is a free video editor designed for simple cutting, filtering and 
encoding tasks. It supports many file types, including AVI, DVD compatible 
MPEG files, MP4 and ASF, using a variety of codecs. Tasks can be automated 
using projects, job queue and powerful scripting capabilities.

Requirements (all available at SlackBuilds.org):
  lame, faad2, faac, a52dec, libdca, xvidcore, and x264

Optional Dependencies (also available at SlackBuilds.org):
  aften, amrnb, jack-audio-connection-kit, libsamplerate