x264 is a free library for encoding H.264/AVC (aka MPEG-4 Part 10)
video streams.

Encoder features
 * CAVLC/CABAC
 * Multi-references
 * Intra: all modes (4x4 and 16x16 with all predictions)
 * Inter P: all partitions (from 16x16 down to 4x4)
 * Inter B: partitions from 16x16 down to 8x8 (including SKIP/DIRECT)
 * Ratecontrol: constant quantizer, constant bitrate, or multipass ABR
 * Scene cut detection

WWW:	http://www.videolan.org/x264.html