Eh... isn't the Joint Photographic Experts Group the one that patents everything?

Nope, they don't patent or even hold the patents, they are just a standards group.

Manned by representatives of patent holder companies...

I'm wondering, what incentive do researchers have to share their new compression algorithms with JPEG? Especially if JPEG patents everything as you suggest.

If it works similarly to other standards groups, they don't take the patents from inventors. Instead, they manage the patents and collect fees on behalf of the (many) holders, allowing anyone to buy the rights through a single entity. The various MPEGs and other formats like DIVX work in this way.

No that isn't true. ISO (MPEG/JPEG) does not play a part in licensing patents or forming patent pools, which is only natural when you consider the fact that ISO is an international organization headquartered in Geneva and every country has its own patent ecosystem.

Individual companies within a certain jurisdiction can certainly set up pools and court the various rightsholders who participate in the standards process, and that is what you see with e.g. MPEG-LA and HEVC Advance in the US. But these have no direct connection to ISO beyond using the name and serving the contributing organizations.

Also, JPEG and MPEG are both part of the same standards group. And Divx is just a brand of MPEG implementations.

Ah, so I accidentally spread FUD because, well... the situation is complicated and confusing.

Sadly I can't edit my top post any more :/

MPEG-LA (the patent pool organizer) isn't MPEG (the standard body), even if the former adopted the latter's name.

The only thing to blame standard bodies for is their dysfunctional approach at patents that incentivizes useless feature stuffing so that all parties have some patents in the mandatory-to-implement part of the spec.

Can they patent it if you disclose it in a paper?

No they cannot, and you cannot either :)

In the U.S., you have one year from the initial date of public disclosure to file a patent application, so you can still patent it after publishing a paper, if you don't wait too long. See 35 U.S. § 102(b)(1), https://www.law.cornell.edu/uscode/text/35/102

Professional curiosity: is that because it would be considered prior art or is there some other provision that covers that kind of thing?

I hope evaluation will use more diverse set of images than the subset given. Only a couple of example images have highly saturated color, and all example images will tolerate poorly done chroma subsampling.

On the web there are categories of images, such as logos, screenshots, renders, large icons, photos with captions, that aren't simple enough to compress well with lossless encoders, but become a mess when compressed with codecs tuned for high-res photos without any sharp highly saturated edges.

Well, it is JPEG, after all. So their focus is most likely photographic pictures. As evident by sentences as »contributors to this challenge may want consider contribution of their technology as input to the ongoing JPEG activity«.

You don't need to subsample chroma in JPEG. I often disable it (use 4:4:4 sampling) if there is high color contrast detail. Say a tree with red fruit, marketplace, kid's toys, etc.

I know it's not necessary in JPEG, but some codecs (especially video and therefore video-codec-derived still image formats) have only 4:2:0 option. And if a codec chooses to use it, I'd prefer the test suite to require it done well.

I've recently looked at it closely and found that almost every codec does chroma subsampling incorrectly, but the error is visible mostly in computer-generated graphics, and rarely in photos, and probably that's why nobody cared to fix it.

https://github.com/mozilla/mozjpeg/issues/193

For most purposes, image compression is a solved problem.

I assume this challenge exists to create a new image compression format. But I don't see any reason why JPEG2000 doesn't happen again - a new format that almost no one adopts. JPEG was simply good enough.

Although 12-bit color depth with JPEG comparable compression levels would sure be nice.

Holy shit do I strongly disagree with this.

> Although 12-bit color depth with JPEG comparable compression levels would sure be nice.

Exactly: there are so many features - like higher bit depth, alpha transparency, different colour spaces - missing form JPEG.

IIRC, JPG2000 wasn't adopted because back in the day we only had Internet Explorer, which required a special plugin, it was too slow, and there weren't many export options.

BPG and FLIF are good contenders in the lossy/lossless area though.

http://bellard.org/bpg/

http://flif.info/

I agree new features would be nice. Like alpha transparency like you mentioned. Or how about cool things like depth or normal maps? I just think almost no one cares. We represent 0.1% of the population.

The last new image format to be universally adopted was PNG in 1996. A lot of entrants have tried ever since, but I think it'd be fair to say none of them mattered the slightest.

This would be a good occasion to have scrutinize the compression algorithm in BPG image format http://bellard.org/bpg/ .