Dirac / News: Recent posts

VLC media player 0.8.2 released with Dirac

VLC 0.8.2 has been released and has support for Dirac encoding and decoding. Dirac is a general-purpose video codec aimed at resolutions from QCIF (180x144) to HDTV (1920x1080) progressive or interlaced. It uses wavelets, motion compensation and arithmetic coding and aims to be competitive with other state of the art codecs.

News at: http://www.videolan.org/#NEWS5

For a full spec on differences between 0.8.1 and 0.8.2 see: http://developers.videolan.org/vlc/NEWS... read more

Posted by Thomas Davies 2005-07-05


Anu and Thomas are giving a talk on Dirac at GUADEC 2005 in Stuttgart. It's at 5pm on Sunday in the Mannheim room. Ralph Giles from Xiph and Wim Taymans from GStreamer are talking in the same session. If you're going we'll see you there!

Posted by Thomas Davies 2005-05-27

New website on test

We've redesigned the project Home Page, which is in the process of testing.

It uses MathML and SVG by default. This means that it occupies less space and we can ultimately bundle the documentation parts of it with the release code. We can't do that at the moment as it uses lots of graphics and makes the download too big.

The site is designed so that if SVG is not supported then GIFs will be pulled in over the web to replace them. This should work even if you have a local copy of the site, although in this case there are some problems with IE.... read more

Posted by Thomas Davies 2005-05-27

Dirac-0.5.2 released

This is a minor release with the following changes:
- Improved decoder speedup by 20%
- Included support for multiple wavelet filter types
- Included support for variable motion vector precision.
- Modified encoder utility command line interface. Refer to
section 4.3 in README for further details.
- Patches provided on project page to include dirac support
in the latest releases of MPlayer, ffmpeg and transcode.
- Minor bug fixes... read more

Posted by Anuradha Suraparaju 2005-05-25

Dirac Directshow Filter

A Directshow filter for Dirac has been released to enable playback of Dirac encoder files using Windows Media Player. Installation instructions are available in the zipped archive on the Dirac project page.

Posted by Anuradha Suraparaju 2005-02-17

MPlayer-1.0pre6a patch to enable Dirac Playback

A patch for MPlayer-1.0pre6a has been released to enable playback to Dirac encoded files.

Posted by Anuradha Suraparaju 2005-02-17

Dirac-0.5.1 released

This is a minor release with several algoritmic improvements and bug fixes. Some of the main improvements are

- Significant speedup in the Arithmetic coding and decoding
- Improved compression performance and decoding speed
- MMX optimisation in Motion estimation resulting in
improved encodin speed
- Released a patch for MPlayer-1.0pre6a to enable it to play
back Dirac encoded files. The patch can be downloaded
from the Dirac project page on Sourceforge.
- Released DirectShow filter for Dirac to enable playback of
Dirac bitstreams using Windows Media Player. The patch
can be downloaded from the Dirac project page on

Posted by Anuradha Suraparaju 2005-02-17

Dirac in LiVES

This message from Salsaman (gfinch@users.sourceforge.net):

"Encoding to dirac is now supported in LiVES (http://lives.sourceforge.net) as of version 0.9.1

Please go there, download and test. You can switch to dirac encoding through Tools | Preferences | Encoding (multi_encoder)"

Posted by Thomas Davies 2005-01-06

Dirac in VideoLAN

krasni tells us that Dirac streaming is now supported in VideoLAN.

Here's the link:


Posted by Thomas Davies 2004-12-22

Dirac-0.5.0 released

This ia a major release with new features and algorithmic improvements. The major changes are

- Added C interface for the encoder application. Refer to
the api documentation in dirac_encoder.h or in the
Programmer's Guide at

- Updated bitstream version. Encoder/Decoder apps in this
release will not be able to decode bitstreams generated
by earlier versions.
- Improvements to Constant Quality encoding engine to
improve stability.
- Speed-ups to motion compensation and wavelet transform
for faster decoding
- Removed rounding errors from motion compensation.
- Fixed bugs with clipping and encoding black or white
- Fixed bug with overflow in context modelling for arithmetic
coding of HD pictures.
- Added unit tests for motion compensation classes and
wavelet classes.
- The number of frames parameter is no longer required. All
existing picture header files must be recreated using
make_header for this parameter to be omitted. Otherwise,
incorrect bit rates will be reported by the encoder
- Updated algortihm documentation.
- Restructured libraries so that only two libraries are
generated - an encoder library and a decoder library.
'make install' will now install only the public API libraries
and header files, the encoder and decoder apps and the
conversion and instrumentation utilities.
- Added support for building shared and/or static libraries
using libtool under UNIX, GNU/Linux. Shared and static
libraries are built by default.
- Added support for building shared or static libraries under
MS Windows using MSYS and the no cost MSVC++ 2003
toolkit. Shared libraries are built by default.
- Added support for building the codec using MS Visual C++
.NET 2003 under MS Windows. Options are available to build
Dlls and static libraries. The _declspec mechanism is used
to export the Encoder and Decoder public "C" API.
- New target 'valgrind-check' added to make under Linux.
- Build under MS Windows using nmake no longer supported.
- Bugs fixed: 1050816, 1055692, 1050757, 1044503, 1044501,
- Patches Applied: 1055714, 1055707, 1061923, 1071429,

Posted by Anuradha Suraparaju 2004-12-01

Dirac Home Page has moved

The Dirac website has moved to http://dirac.sourceforge.net.
Please update your bookmarks to point to this site. The old site hosted at BBC R&D will no longer be maintained and will be modified to re-direct you to the new site.

Posted by Anuradha Suraparaju 2004-11-02

Enhancements to Dirac

We've added a document describing potential enhancements to the Dirac algorithm on our docs page (http://www.bbc.co.uk/rd/projects/dirac/documentation.shtml).

There's an overview of a number of additions that people have suggested we make, including interlace coding, global motion compensation, and various quantisation schemes. These aren't fixed in stone, and comments/suggestions are very welcome.

Posted by Thomas Davies 2004-09-22

Dirac-0.4.3 released

This is a minor release with the following enhancements and bug fixes
- Quality metric has changed from PSNR to one based
on 4th powers of errors. This results in pictures with
more stable quality and fewer artefacts.
- Fixed bug with scaling motion vectors for non 4:4:4
- Fixed bug in encoder in downconverting a picture with
odd valued dimensions
- Fixed bug in encoder in handling input with 4:1:1
chroma format.
- Fixed bug in diagnostics tool in handling input with
4:1:1 chroma format.
- Updated algorithm documentation

Posted by Anuradha Suraparaju 2004-09-21

Dirac-0.4.2 release

This release is a minor release with the following bug fixes
- Fixed bug in writing insrumentation data to file during the encoding process.
- Fixed bug with setting DC band perceptual weight
- Fixed bugs in diagnostics tool.

Posted by Anuradha Suraparaju 2004-09-10

Dirac-0.4.1 released

This release is a minor release with fixes to bugs in the motion estimation process while encoding and a build time error. It also includes support for building under MS Windows using MSYS and the no-cost MS VC++ 2003 compiler.

Posted by Anuradha Suraparaju 2004-08-26

New documentation on website

We've added new documentation to the Dirac website (http://www.bbc.co.uk/rd/projects/dirac/documentation.shtml).

We've updated the FAQ, the algorithm documentation, and posted the doxygen-generated API docs to cover release 0.4.0.

We've also posted documentation on the diagnostic tool included in 0.4.0. This allows you to view the encoder decisions to see what it's doing and how it might be going wrong. ... read more

Posted by Thomas Davies 2004-08-23

Dirac-0.4.0 released

This version is a major release and contains many improvements over version 0.3.x.

The main features are

- Added constant quality encoding interface using PSNR
as the quality measure, and using multi-pass frame

- Implemented unique frame headers to facilitate bit-stream
parsing. The document describing the syntax of Dirac
bitstream v0.1 is included in the doc directory.

- Added C interface for the decoder application to allow
interfacing to player software. Refer to the api documentation
in dirac_parser.h.... read more

Posted by Anuradha Suraparaju 2004-08-19

Dirac Version 0.3.1 released

This is minor release to resolve building under Windows and correct minor bugs in the video conversion utilities

Posted by Tim Borer 2004-06-09

Dirac Version 0.3.0 is here!

Dirac Version 0.3.0 has been released. The new version contains many improvements over Version 0.2.0 as well as various bug fixes and code refactorization.

Features include:

- New conversion utilities for going between raw RGB and all YUV formats, as well as between RGB and bitmap files

- A fix for serious artifacts when frame dimensions are not multiples of the chosen block dimensions. All combinations of frame size, block parameters and chroma formats are now supported.... read more

Posted by Thomas Davies 2004-05-28

Announce and Commits mailing lists

New mailing lists dirac-announce and dirac-commits have been created.

dirac-announce will contain news of significant developments in Dirac

dirac-commits is for those interested in the development side. It automatically logs any commits to the CVS.

dirac-developers and dirac-discuss have been discontinued. All discussion now takes place on the public forums.

Posted by Thomas Davies 2004-05-28