Slashdot Mirror
Interview With BBC Dirac Developer Thomas Davis
arclightfire writes "The subject of the BBC video codec Dirac has been here before, but we've managed to get an interview with Thomas Davies, Senior R&D Engineer at the BBC who devised the Dirac algorithm. Interesting to note that the codec should be with Mplayer soon; "As far as players go, we'll be submitting a patch to Mplayer to allow it to play Dirac pretty soon." And info about the tech developments in Dirac; "I used tried and techniques, like wavelets, which weren't in standards at the time, and tried to develop them. And that's what we'll continue to do as the algorithm develops. So we've tried to build on some pretty well-understood technology, and also tried to do some new things with it. We're patenting the new stuff, quite a bit of which hasn't got into the software yet. The license means that these patents are licensed for free within the Dirac software.""
h.264 (now formally known as AVC, the video-equivalent of AAC) is maturing. Well, at least Ahead's Nero Digital implementation of h.264 is maturing. The marketing spin has it called Nero Digital, but it's fully h.264 compliant. And the results are impressive - beta testing shows comparable quality of XviD at half the bitrate.
H.264/AVC is open and extremely powerful. Why bother with another protocol?
From Apple Tiger h.264 page:
Not only is H.264/AVC very efficient, providing extremely high quality in smaller files, but H.264/AVC is also scalable, producing video for everything from 3G for mobile phones to High Definition (HD). H.264/AVC can create great-looking 3G mobile content at 50-160 Kbps, excellent Standard Definition (SD) video at 800-1500 Kbps, beautiful HD video (1280x720, 24p) at 5-7 Mbps and full HD video (1920x1080, 24p) at 7-9 Mbps. So at today's SD DVD data rates, H.264/AVC can deliver full HD. In fact, H.264/AVC was ratified by the DVD Forum for inclusion in the next-generation HD DVD format.
The license costs on H.264 are the most expensive on the planet (MPEG LA controls it with a hell of a lot of patented stuff from various companies). This is why it isn't being adopted rapidly. Even MS undercut it with cheaper licensing on Windows Media. This will kill it, a very nice technology. I am all for open source codecs. Perhaps BBC is on to something.
Sorry for the double post, but it needs to be formatted properly
:-p )
Dirac + ogg in an mkv container could save your soul
I assume you mean Dirac + Vorbis in Matroska... Ogg is a container format like matroska... (what you said was akin to DivX + AVI in ASF
On a related topic, Matroska is an unfortunate format to use. It is very inefficient, both in CPU time, and in overhead. My computer can play a 640x480 divx in an avi, but can't play a 512x384 divx in matroska. Additionally, matroska has a higher file overhead than asf or quicktime.
Ogg is a good, basic format. It could be seen as a sturdy replacement for AVI. Matroska doesn't do anything beyond even the Quicktime format... and quicktime is vastly more efficient.
Anyway, moving on from that rant. I agree strongly with your other points. If you have a choice between two, largely equivalent codecs, one is unencumbered by laws and one is, why would you choose to use the one that is. Sure you might not get sued straight away, or even for a year or two, but why bother with that risk at all?
I am not particularly bothered with pirating certain commercial software, but if there is a free program that does everything I need, I will use that over a pirated of a commercial program. Why take the risk when there is another option?
Both a C interface to our encoder and direct show filters are on our road map. Monitor our site or check freshmeat to find out as soon as they arrive. Please bear in mind we are only in alpha.
Dirac is licensed under the MPL (Mozilla) triple license. This means it is primariliy licensed under the MPL but anyone is free to re-license under either the GPL or LGPL licenses. We used the Mozilla license becuase it is well known and deals with patent issues. It means that any patents the BBC can license relating to the software are implicitly and irrevocably licensed for the software. So there are no royalties to pay for developing or using this software (either encoder or decoder). We chose this license to try to ensure that the codec remains royalty free. We figured if it was good enought for the Mozilla project it would probably be OK for us too. On the other hand we are aware that the MPL, on its own, is incompatible with the GPL and LGPL. We didn't want this and so have allowed re-licensing under the GPL. This means GPL software can freely integrate and develop Dirac. This is the approach suggested on the Gnu license page. You can also license Dirac under the LGPL. This means that even proprietary software can use it if they dynamically link with the libraries. The reason we have done this is so that the widest range of users can use Dirac royalty free.