Dirac 1.0.0 Released

dylan_- writes "According to their website, 'Dirac is an advanced royalty-free video compression format designed for a wide range of uses, from delivering low-resolution web content to broadcasting HD and beyond, to near-lossless studio editing.' Now a stable version of the dirac-research codebase, Dirac 1.0.0, has been released. The BBC have already successfully used the new codec during the Beijing Olympics and are looking to push it to more general use throughout the organisation. The latest version of VLC (the recently released 0.9.2) has support for Dirac using the Schroedinger library."

Comments

Re:really?

[whathappenedtomonday]

Read their site. From the FAQ:

Do you infringe any patents?

The short answer is that we don't know for certain, but we're pretty sure we don't.
We haven't employed armies of lawyers to trawl through the tens of thousands of video compression techniques. That's not the way to invent a successful algorithm. Instead we've tried to use techniques of long standing in novel ways.

What will you do if you infringe patents?

Code round them, first and foremost. There are many alternative techniques to each of the technologies used within Dirac.
Dirac is relatively modular (which is one reason why it's a conventional hybrid codec rather than, say, 3D wavelets) so removing or adding tools was relatively easy, even though this may mean issuing a new version of the specification.

News from OGG Theora, too!

[c0l0]

Dirac isn't the only royality-free, patent-unencumbered video codec there is - Xiph's OGG Theora has been around a while already, yet failed to impress quality-wise up until recently. There's some really cool development going on however, and you may see some of the results achieved over there: http://xiphmont.livejournal.com/35363.html

It's noteworthy that the changes made only affect the ENCODER, thus no changes to the DECODER (the part of a codec all applications used to play back files have included) are necessary. This bodes very well for HTML5, which will include some support for Theora on at least Mozilla (and iirc Opera) browsers.

Re:News from OGG Theora, too!

[delt0r]

In sound the idea of masking works really well. That is if there is a loud sound at a particular frequency we tend to not be able to hear sounds that are a low in pitch and a bit quieter (IIRC). Its effectively masked. The other big advantage is also the linear nature of sound.

But the human visual system is a *lot* more complicated. IIRC about 1/3 or our brains are used for visual perception. Currently we use PSNR (Peek signal to noise ratio) as a measure. But this has been shown many times to be a very poor indication of what we perceive. One example is blocking. Blocking cause straight lines to form in the image and our brains lock on to them far more quickly that other artifacts.

Next is the colour and the 2d nature of a image. Then add that the eyes do a bunch of preprocessing on motion perception and its getting quite difficult. Finally we have the method of comparison. Which often involves comparing still images from the video stream. Yet if thats a high motion scene the codec might be better off encoding these frames with low quality because we can't perceive the quality loss combined with fast motion.

Lets also not forget how many people think youtube is good quality or at worse, good enough!

Re:Open source overkill

[MrWim]

The GPL makes assurances regarding patents that the MIT license doesn't:

"Each contributor grants you a non-exclusive, worldwide, royalty-free patent license under the contributor's essential patent claims, to make, use, sell, offer for sale, import and otherwise run, modify and propagate the contents of its contributor version."

So if you use it as a GPL licensed library you can't get sued by the BBC or other contributors to the code.

Re:Performance? Benefits?

[Tab is on Slashdot]

How does it stack up to other codecs?

As I say below, unfortunately the quality is lacking compared to modern codecs like H.264 and even (dare I say) VC-1. Apparently that's just the nature of using wavelets. While they give a very natural style of compression on still images (JPEG-2000, etc), they do not translate well to moving sequences because, unlike all other current codecs, the image is not broken up into blocks that can then be tracked and diff'd in time. Still, it'll be interesting to follow Dirac, if only because they're taking a radical new approach with only Michael Niedermayer's Snow as a peer.

Re:0xBBCD

[Bloater]

the fourcc is 'drac'

Re:Performance? Benefits?

[delt0r]

As I state below. Most of codecs performance has to do with the encoder. At 1.0.0 its too early to tell if the format/codec design is limited.

However a great codec without a good encoder is no good at all. But its early days yet considering h.264 has been around for 5+ years.

Re:really?

[David Gerard]

Encoding and decoding is presently fat and slow. It's very much in development.

Re:Performance? Benefits?

[Tab is on Slashdot]

Dirac employs wavelet compression, instead of the discrete cosine transforms used in most older codecs (such as H.264/MPEG-4 AVC or SMPTE's VC-1). Dirac is one of several projects attempting to apply wavelets to video compression. Others include Rududu [2], Snow and Tarkin. Wavelet compression has already proven its viability in the JPEG 2000 compression standard for photographic images.

Yes it does :|

Re:0xBBCD

[dougisfunny]

The size of a byte doesn't have to be 8 bits, though it usually is.

Re:Open source overkill

[Anonymous Coward]

Yes - GPL says that explicitly, bit MIT (copyright holders) grant you:

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so ...

So they GRANT you to do with it more less anything, even if they own patents and they can not take their word back and saying ... ops, we're sorry, we have some patents, so we will sue you now.

Of course they can not grant you immunity to third party patents, but neither GPL guys...

Re:Open source overkill

[dapyx]

No, the GPLv3 has clauses about using the code in a DRM system, the anti-patents clause has been for a long time.