x264 is a library for creating H.264 video streams. It is not 100%
complete, but currently it has at least some kind of support for most
of the H.264 features which impact quality. There are also many
advanced features in the H.264 specification which have nothing to do
with video quality per se; many of these are not yet implemented in
x264.
Encoder features
CAVLC/CABAC
Multi-references
Intra: all macroblock types (16x16, 8x8, and 4x4 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, single or multipass ABR, optional VBV
