Avidemux

Edit videos in a non-linear way, add effects and convert between various formats, including AVI, FLV, MKV, MPG, MPEG, MP4, OGM, VOB, and WebM. Apply ported filters from MPlayer and Avisynth, extract or add audio to your movies. View subtitles processing, including SUB, SSA, ASS, and SRT. The program supports command line usage.