x264 - a free h264/avc encoder

x264 is a free library for encoding H264/AVC video streams. The code is written from scratch by Laurent Aimar, Loren Merritt, Eric Petit (OS X), Min Chen (vfw/asm), Justin Clay (vfw), Måns Rullgård, Radek Czyz, Christian Heine (asm), Alex Izvorski, and Alex Wright. It is released under the terms of the GPL license.

Development status

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, single or multipass ABR, optional VBV
• Scene cut detection
• Adaptive B-frame placement
• B-frames as references / arbitrary frame order
• 8x8 and 4x4 adaptive spatial transform
• Lossless mode
• Custom quantization matrices
• Parallel encoding on multiple CPUs
• Interlacing

Getting x264

The latest x264 source code can always be found by anonymous Git repository:

# git clone git://git.videolan.org/x264.git

Or grab a daily tarball.

Unofficial builds for Windows are available from Jarod or Sharktooth.

Support

For support information and to ask questions, you have the following possibilities:

A mailing list (x264-devel), a forum (Doom9), and IRC (#x264@freenode).

Bugs

Please report any bugs to the mailing list. If it is a crash, then compile x264 with `./configure --enable-debug` and follow the ffmpeg bugreporting guidelines.

Software using x264

• Avidemux
• ELDER
• ffdshow
• ffmpeg
• GordianKnot
• Handbrake: a multi-platform, multithreaded DVD to MPEG-4 ripper/converter.
• LiVES
• MeGUI
• MEncoder
• pspVideo9
• RealAnime
• StaxRip
• TCVP
• VLC media player: a cross-platform video player and streaming solution.

People using x264

• Google Video
• MobileASL
• Speed Demos Archive
• TASvideos

If you use x264 in another project, let us know !

Awards

2005 December 26 -- x264 won Doom9's 2005 codec shoot-out, passing Ateme by a hair.

2005 December 12 -- x264 tied for 1st place (with Ateme) in the second annual MSU MPEG-4 AVC/ H.264 codecs comparison.