X264

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x264
Developer:	x264 team
OS:	Cross-platform
Use:	Multimedia framework
License:	GPL
Website:	http://developers.videolan.org/x264.html

x264 is a free software library for encoding H.264/MPEG-4 AVC video streams. The code is written by Loren Merritt, Laurent Aimar, Eric Petit, Min Chen, Justin Clay, Måns Rullgård, Radek Czyz, Alex Izvorski, Alex Wright, and Christian Heine from scratch. It is released under the terms of the GNU General Public License, but this license may be incompatible with the MPEG-LA patent licenses in jurisdictions that recognize software patents.

Several graphical user interfaces have been made for the command line version, including MeGUI, AutoAC and a .NET (1.1) based x264CLI GUI.

x264 has a strong user community based at Doom9 where discussions for improved development take place.

Contents 1 Capabilities 2 Comparison with other codecs 3 Projects using x264 4 See also 5 External links

[edit] Capabilities

As of October 2006, it is one of the most advanced publicly available AVC encoders. It is also one of only a few publicly available High Profile AVC encoders. It supports:

• Context-based Adaptive Binary Arithmetic Coding (CABAC) and Context-based Adaptive Variable Length Coding (CAVLC)
• Multiple reference frames
• All intra-predicted macroblock types (16x16, 8x8 and 4x4 -- 8x8 is part of AVC High Profile)
• All P-frame inter-predicted macroblock types
• B-Inter-predicted macroblock types from 16x16 down to 8x8
• Rate Distortion Optimization
• Multiple ratecontrol modes: constant quantizer, constant quality, single or multipass ABR with the option of VBV
• Scene cut detection
• Adaptive B-frame placement, with the option of keeping B-frames as references / arbitrary frame order
• 8x8 and 4x4 adaptive spatial transform (High Profile)
• Lossless mode (High 4:4:4 Profile)
• Custom quantization matrices (High Profile)
• Parallel encoding of multiple slices
• Interlace support

[edit] Comparison with other codecs

x264 has won awards in the following codec comparisons:

• Doom9's 2005 codec shoot-out [1]
• Second annual MSU MPEG-4 AVC/ H.264 codecs comparison [2]
• MSU Subjective Comparison of Modern Video Codecs [3]

See also the Software encoder feature comparison in the H.264/MPEG-4 AVC article.

[edit] Projects using x264

• Avidemux
• ffdshow
• ffmpeg
• Gordian Knot
• Handbrake: a multi-platform, multithreaded DVD to MPEG-4 ripper/converter.
• MeGUI
• MEncoder
• pspVideo9
• RealAnime
• StaxRip
• TCVP
• VLC media player: a cross-platform video player and streaming solution.
• MPlayer
• VisualHub
• VirtualDub
• x264 QuickTime Codec: x264 wrapped in a QuickTime codec.

[edit] See also

• H.264
• MPEG-4
• Codec
• Video

[edit] External links

• x264 Home Page
• Doom9 forum about MPEG-4 AVC codecs (x264, NeroDigital AVC, etc.)
• ffmpegX GUI for Mac OSX including x264 support
• Downloads:
  • Official source code snapshots
  • The latest x264 builds daily (x264.nl)
  • Sharktooth's builds (at Doom9)
  • DeathTheSheep's up-to-date vfw - builds