x264 is a free softwarelibrary and application for encoding video streams into the H.264/MPEG-4 AVC compression format, and is released under the terms of the GNU GPL.
Download x264The x264 encoder supports using an adaptive number of B-frames rather than just a fixed pattern like IBBPBBPBBPBB, and this setting controls that adaptive decision. X264's default is a fast, simple algorithm (1), but it also supports a slower, higher quality, 'optimal' algorithm (2). The slow algorithm is the default for the quality-oriented. Getting Started with x264. X264 is a free AVC encoder that is best-in-class and thanks to compliance testing from the Criterion Collection now supports Blu-ray Disc encoding. GDMX has also vetted x264 for BD use using the Eclipse Verifier in 1080p24 and 1080p/i30. This page deals with the most common scenarios for Blu-ray authoring. The game optimized encoder settings are currently only available when using software (x264) encoding and using Twitch as streaming service. If you use both, you can then enable the 'use optimized encoder settings' found in the Go Live pop-up, where you set your Game and Title. The profile selection is only in effect when 'Use optimized encoder.
master • Source • 750kBFeatures Overview
- Provides best-in-class performance, compression, and features.
- Achieves dramatic performance, encoding 4 or more 1080p streams in realtime on a single consumer-level computer.
- Gives the best quality, having the most advanced psychovisual optimizations.
- Support features necessary for many different applications, such as television broadcast, Blu-ray low-latency video applications, and web video.
- x264 forms the core of many web video services, such as Youtube, Facebook, Vimeo, and Hulu. It is widely used by television broadcasters and ISPs.
Getting x264
Source
The latest x264 source code is available through git repository:
You can browse the source on-line.
Application binaries
Official builds for Windows, Linux, and MacOSX are available from here.
News
2013 August 23 — The x264 Development Newsletter: Volume 39 is out.
2013 July 4 — The x264 Development Newsletter: Volume 38 is out.
2013 May 20 — The x264 Development Newsletter: Volume 37 is out.
2013 May 4 — The x264 Development Newsletter: Volume 36 is out.
Encoder features
- 8x8 and 4x4 adaptive spatial transform
- Adaptive B-frame placement
- B-frames as references / arbitrary frame order
- CAVLC/CABAC entropy coding
- Custom quantization matrices
- Intra: all macroblock types (16x16, 8x8, 4x4, and PCM with all predictions)
- Inter P: all partitions (from 16x16 down to 4x4)
- Inter B: partitions from 16x16 down to 8x8 (including skip/direct)
- Interlacing (MBAFF)
- Multiple reference frames
- Ratecontrol: constant quantizer, constant quality, single or multipass ABR, optional VBV
- Scenecut detection
- Spatial and temporal direct mode in B-frames, adaptive mode selection
- Parallel encoding on multiple CPUs
- Predictive lossless mode
- Psy optimizations for detail retention (adaptive quantization, psy-RD, psy-trellis)
- Zones for arbitrarily adjusting bitrate distribution
Awards
2010 May 25 — x264 won MSU Sixth MPEG-4 AVC/H.264 Video Codecs Comparison, with ~24% better encoding than second place.
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.
Support
For support information and to ask questions, you have the following possibilities:
A mailing list (x264-devel), IRC (#x264@libera and #x264dev@libera) and Issue Tracker.
Bugs
How To Use X264 Encoder
Please report any bugs on the Issue tracker.
If it is a crash, then compile x264 with ./configure --enable-debug and follow the ffmpeg bugreporting guidelines.
Licensing
In addition to being free to use under the GNU GPL, x264 is also available under a commercial license. Contact x264licensing@videolan.org for more details.
Software using x264
- …and many more
X264 Codec
If you use x264 in another project, let us know!