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Dirac 1.0.0 Released
Posted by
timothy
on Sat Sep 20, 2008 01:13 PM
from the open-standards-the-movie dept.
from the open-standards-the-movie dept.
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."
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really? (Score:3, Insightful)
Remember when we all used GIF until somebody came out of the closet with a patent claim. How can we be sure about this one?
Re:really? (Score:5, Informative)
Read their site. From the FAQ [diracvideo.org]:
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.
Parent
Re: (Score:3, Interesting)
The real question is, how does it fare against good H.264 encoders e.g. x264? And how are the encoding speeds?
The few comparisons I've seen put H.264 as having the edge when it comes to both, but not by a lot.
Re:really? (Score:5, Informative)
Encoding and decoding is presently fat and slow. It's very much in development.
Parent
Re:really? (Score:5, Interesting)
Since you claim this I assume that you tried the 1.0.0 already - I watched the promo vid, and it says the BBC is using the codec to handle HD content over their standard def infrastructure at very low latency (a few ms, if I remember correctly).
Nonetheless, this seems to be an interesting thing to keep an eye on, because the codec specs address good compression especially for very high bandwidths, which is going to be an important issue for movie post production/processing, HD content and the likes. The promo vid is well worth watching.
Parent
Great, but... (Score:5, Funny)
I tried using the Schrodinger library but I'm uncertain it works. Plus, I can't find my cat.
Re:Great, but... (Score:5, Funny)
Plus, I can't find my cat.
Be glad for that, as long as you dont you might still have one.
Parent
Re: (Score:3, Funny)
I had success integrating Dirac, and got a result of 1.
Re:Great, but... (Score:5, Funny)
I tried using the Schrodinger library but I'm uncertain it works. Plus, I can't find my cat.
I hate to tell you, but your cat is dead. And/or not.
Parent
Re:Great, but... (Score:4, Funny)
You may have loaded libheisenberg instead. They sometimes become entangled.
Parent
0xBBCD (Score:5, Interesting)
I see the first 4 bytes are 0xBBCD.
British Broadcasting Corporation Dirac.
Re: (Score:2, Interesting)
Did you mean to say the FOURCC (which is usually not the first four bytes) is 'BBCD'? 0xBBCD is usually two bytes...
Re:0xBBCD (Score:5, Informative)
the fourcc is 'drac'
Parent
Re:0xBBCD (Score:5, Insightful)
Isn't that just 2 bytes? :)
*nibbles on parent's geek card*
Parent
Re: (Score:2)
Re: (Score:2, Informative)
The size of a byte doesn't have to be 8 bits, though it usually is.
Re:0xBBCD (Score:4, Funny)
Parent
Open source overkill (Score:5, Interesting)
From the FAQ:
What are the license conditions?
The Schrodinger software is available under any of the GPLv2, MIT or MPL licences. Libraries may also be used under LGPL.
Sounds like someone wanted there to be no question about whether it was open source.
Re:Open source overkill (Score:5, Funny)
The Schrodinger software is available under any of the GPLv2, MIT or MPL licences. Libraries may also be used under LGPL.
Sounds like someone wanted there to be no question about whether it was open source.
Sounds to me like the license exists in multiple states at once, which may be exactly the way Schrodinger would have liked it.
Parent
Re: (Score:2, Insightful)
I am not sure, but isn't MIT one good enough to relicense it to (L)GPL or MPL?
Re:Open source overkill (Score:5, Informative)
"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.
Parent
Performance? Benefits? (Score:4, Insightful)
How does it stack up to other codecs?
Do we need another codec?
Re:Performance? Benefits? (Score:5, Insightful)
Parent
Re: (Score:3, Interesting)
Matroska is not a codec. It is a container format, and it beats any closed-source competitions hands own on features (e.g. as far as I know it is the only format that supports embedding custom TrueType fonts for subtitles).
The best video encoding combo right now is:
- Matroska as the container
- H.264 for video
- Ogg Vorbis for audio
- ASS for subtitles
Re: (Score:3, Interesting)
How does Vorbis really compare against AAC? Besides the whole royalty/patent free issue, does Vorbis really beat out AAC? (Ignoring royalty/patent issues here because you also mentioned H264)
Re: (Score:3, Interesting)
But if you're just distributing the source..
So now I can't also distribute binary but my freedom is not affected? I don't think I would want to test source=ok, binarys=!ok as far as patent law is concerned with my wallet. Economic harm is all thats needed if software patents are valid.
Theoretically true, although that hasn't happened much in practice, at least in this space.
So you pay a crap load of money and only don't get sued much? Thats a raw deal. There has been at least one case I know of with mpeg4 | h.264, and thats a lot more than what both theora and dirac have had to deal with. Add the fact that theora is based on VP3 with a act
Re:Performance? Benefits? (Score:5, Informative)
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.
Parent
Re:Performance? Benefits? (Score:5, Informative)
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.
Parent
Re: (Score:2, Funny)
The codec is new, give it a few months.
Early DVDs looked like shitty 90% compressed jpegs too, you know.
Re: (Score:3, Interesting)
Re:Performance? Benefits? (Score:5, Informative)
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 :|
Parent
Content (Score:5, Interesting)
News from OGG Theora, too! (Score:5, Informative)
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 [livejournal.com]
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! (Score:5, Interesting)
Parent
Re:News from OGG Theora, too! (Score:5, Insightful)
Both Theora and Dirac have plenty of space to move with regard to encoders.
However there is no easy way to measure "distortion" of the encoded image that matches the human visual system all that well. (unlike audio). But I expect most codecs to get better in the next few years because of encoders. (including h264).
Ironically h264 does so well because of the availability of a free, fast and good quality encoder done my the community. Not the license owners.
Parent
Re: (Score:3, Insightful)
However there is no easy way to measure "distortion" of the encoded image that matches the human visual system all that well. (unlike audio).
How do you objectively measure psychoacoustic distortion? Do the same techniques not apply to vision simply due to unknown constants or is there some more fundamental reason?
Re:News from OGG Theora, too! (Score:5, Informative)
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!
Parent
Re: (Score:2)
However there is no easy way to measure "distortion" of the encoded image that matches the human visual system all that well. (unlike audio)..
I'm not sure I agree with that...and I think the fact that there are people who *can* tell the difference between a 256kbs MP3 and CD-audio and those who *can't* perhaps shows that there's no easy way to map quality of audio onto something that matches human perception. There are plenty of technical ways however, both for audio and visual. I'm not sure where you're getting this from.
Re:News from OGG Theora, too! (Score:5, Interesting)
I don't doubt that some people can tell the difference between flac and mp3/ogg/aac. But the true number is far less than the claimed number (do a proper blind test to really find out). Also you don't design codecs for 0.5% of the population that can hear the difference, but for the 90% that can't and the other 9.5% that don't care.
Now its a fact that PSNR is used in most encoders. Its also widely recognized that it is not a good measure. I have done my own image compression and got better PSNR than jpeg per bit, and yet it looked far worse.
So I'm not really sure where you getting the idea that is even in the same category as audio.
Parent
Re:For low values of success (Score:5, Insightful)
Could it be that the BBC's slowness to offer HD is related to the fact that most license payers receive their broadcasts via analogue or "Freeview" digital, neither of which currently support it? I guess they have better things to spend their limited budget on.
Parent
Re:For low values of success (Score:5, Insightful)
Parent
Re: (Score:3, Interesting)
I strongly disagree that "most of the improvement has come from the change to digital, not HD". TVs don't magically become a higher resolution when you add a digital decoder! The main benefit(?) of digital has been more channels.
I see a huge difference in quality between SD and HD. The most damaging thing for HD that I've seen is that many retailers used to play SD content on HDTVs, which isn't particularly suited for a TFT/LCD screen and can look terrible.
Re:For low values of success (Score:4, Interesting)
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Re: (Score:3, Insightful)
Re: (Score:3, Funny)
And I thought that was some kind of UK New Wave artsy Duane Hopkins/dogma thing they were going for.
Once again, I mistake incompetence for artistic innovation.
Re:For low values of success (Score:5, Insightful)
Parent
Re: (Score:3, Funny)
Thanks for your support, TV licensees of Britain!
Uh, that's OK. Just send me some money, and I'll make sure it gets passed on to the right pub... I mean people.
Re: (Score:3, Insightful)
Re: (Score:3, Interesting)
I downloaded the code from sourceforge and compiled the code using Visual Studio 2008.
Looks like the encoder is distributed in source format only. I could not locate any pre-built binaries.
I am having trouble figuring out what the command-line parameters mean from the README supplied in the source tarball.
This certainly needs better documentation for non technical users.
The samples certainly look impressive. I will try to compare it against my current favorite encoder -- x264 -- over the weekend.
Re: (Score:3, Interesting)
Took me a while to figure I needed to use YUV input. :(
Unfortunately, it looks like Dirac is no match for x264.
Even VC-1 beats Dirac.