• 13.07.2011

Demo page was updated with english translation.

  • 08.07.2011

Codec installer was updated with english documentation. Also english documentation page was updated.

Source code of the decoder was updated.

  • 04.07.2011

New version of codec released.

Main changes:

  • Motion detection engine was restructured and optimized for multithreaded operation (up to 32 threads). In current code multithreaded optimization is done using a temporal scheme since the core of SIF transform is the last big unit of code that is not working in multithreaded mode.
  • Added multithreaded modes of an entropy codec operation (up to 8 threads). Thus, the decoder now have full multithreading support and supports decoding of streams with 80+ mbits bitrate.
  • Codec now supports vertical resolution that is not a multiple of 16.
  • Implemented different (in terms of speed & quality) motion detection engine presets.
  • Added checking for correct input. Now the decoder doesn't crash on corrupt or invalid files.
  • Added turbo first pass mode - about two times faster than second in two-pass mode.
  • New PsyRD extrapolation engine, used in the motion detection engine, is written. Due to this, another significant improvement in sharpness and detail of compressed image was achieved..

Since compression quality was significantly improved, page with demonstration video samples was updated.

Also comparison of SIF1 and x264 - the best H.264 encoder, was added to demo page.

  • 25.05.2011

Publication of the SIF1 video codec specification was started thanks to joining Valiulin Ivan to the project.

Text of the specification is under «Creative Commons Attribution 3.0 Unported» license. Intellectual property described in this specification is under SIF1 Specification license. Thus, any person can make and use compatible with SIF1 codec without paying any royalties.

  • 03.06.2010

New version of codec released.

Main changes:

  • Massive code restructuring in motion compensation engine was made. Main goal was to get rid of global variables in the code. They disturb to multithreaded code execution and don't allow having multiple copies of decoder in one process.
  • All main calculation units of the decoder were optimized for multithreaded operation. As the result decoding of FullHD video is now possible on any modern dual-core processor with at least 2Ghz clock speed. Current code supports up to 32 simultaneous decoding threads. The only unparalleled unit in decoder is entropy codec. Special multithreaded modes with support up to 8 threads would be implemented in next versions.
  • Parameters of the SIF compression core were optimized and psycho-visual model was improved. At the result sharpness and detail of compressed image were significantly improved.
  • Fixed bug in compression core that appeared when vertical image resolution was not a multiple of 32.
  • Fixed bug in codec that lead to crash on old machines without SSE instruction set support. Thanks to Alexander Budchanin for testing.

Since compression quality was significantly improved, page with demonstration video samples was updated.

Also source code of decoding library was updated with all changes that I have made.

  • 19.04.2010

About new version of codec:

I have made main part of what was planned for new codec version. Herewith I'm quite pleased with the result. In particular significant compression efficiency improvement was obtained. At the same time, I haven't completed multithreaded decoder yet, so I don't want to release codec when decoder is not ready. If everything would be right, I'm planning to finish multithreaded decoder in a month. Unfortunately, it's all depends on how much free time I will have, but this value is hardly predictable.

  • 18.10.2009

As promised, source code of SIF1 decoder was published. Source code is released under open license - derivative of Mozilla Public License 1.1.

Also English content was significantly updated. I'm planning to made full English version in future, but for now it's in a such form.

  • Published English version of codec settings.
  • Published English version of easy-to-understand description of SIF compression technology.
  • Published English version of demonstration video samples.
  • Also codec installer was updated. But for those who have downloaded previous version of installer there is no point in downloading this version since only English documentation was added.
  • 07.10.2009

Sif-project is alive!

Moreover in all years of it underground existence it was actively developing. And at this moment it passes to the next stage of it evolution.

  • Firstly, I've released first release (not alpha) version of SIF1 codec. Comparing to the previous version improvements in quality of compression aare enormous!
  • Also I published text of the patent on the technology of SIF compression. And I've wrote easy-to-understand description of new technology.
  • And the main thing. I'm going to release source code of SIF decoder under open license and to publish open specification of the new standard. It will happen in nearest time, as soon as some documents would be furnished. At the same time I'm not going to open the source code of the encoder.

Unfortunately, I wasn't able to maintain compatibility of the final version with older versions. But this is more than compensated by the huge improvement in the quality of compression.

Main changes:

  • All codec units except compression core were rewritten almost completely. At the same time analyzing part of the codec was improved.
  • Gained huge improvement in visual quality of compression.
  • Added full range of modes that are necessary for practical use of codec. Also special modes suitable for streaming video were added.
  • Refined and improved psycho-visual model of compression. At this moment it's the best psycho-visual model that have ever been realized in codecs.
  • In this version format was completely finalized and would be released as an open specification. All further improvements would be issued in the form of extensions to the standard and also would be published.
  • This version is not compatible with all previous versions but this is the last significant changing of the format. It pays off by significant improvement in quality of compression and much better portability of the new format.

Significant changes on the site were made.

  • Written detailed instruction for using à new codec settings.
  • Updated page with demonstration video samples. Added lot of new examples including video encoded with FullHD quality.
  • Published text of the patent on SIF compression technology.
  • Easy-to-understand description of SIF compression technology was written.
  • New version of codec was released.

I must apparently explain why the project was underground for so much time. After the release of last version I've made decision to make SIF1 an open standard. But for this purpose I had to make rights on the developed technology, and main - bringing the operation level of all units to the releasing level. That's because already published final specification can't be changed and poorly designed units could interfere with project development in future. First of all it concerned units of quantization and entropy compression. The goal was to make possible efficient realization of existing compression engine on different devices - phones and so on. For this purpose it was completely rewritten under the usage of binary interval coding. Unfortunately, this made the new version of codec incompatible with the older versions, but the range of devices on which the new codec can be effectively applied was significantly increased. During the development of new units it was pointless to release intermediate version because their format was incompatible with both past and future versions of the codec. And when everything was worked out I released the final version (by the format) of the codec.

I want to thank Eugene Shelvin for consultation on the binary entropy compression.



 


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