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JPEG2000 Coming Soon
Sonny writes "In a few months time, internet users will be able to make use of the JPEG2000 standard which, its developers claim, enables web graphics to be downloaded much faster than is currently possible. This will not only make graphics-heavy web pages easier to download, it will also preserve image quality. The JPEG standard compresses image files which are then transmitted across the web faster than uncompressed files. Now, researchers at universities around the world have developed JPEG2000, the next-generation image-compression technology under the auspices of the International Standards Organisation. It is the first major upgrade of the standard since it first appeared in the early '90s. What is also important about the technology is its ability to send files without loss of data, which is not the case with current JPEG files. To take advantage of a JPEG2000, web browsers will need a Plug-In for either Internet Explorer or Netscape browsers. These free plug-in's are expected to be available later this year. The extension for the new files will be ".jp2"."
What is also important about the technology is its ability to send files without loss of data, which is not the case with current JPEG files.
JPEG does support a lossless mode, it's just that no one uses it. To paraphrase, JPEG supports a lossless spatial algorithm that operates in the pixel domain. Some amount of prediction is used, resulting in about 2:1 compression, but the error terms for the predictions are included in the data stream (encoded using either Huffman or arithmetic coding), resulting in no net errors.
What's a lot more exciting is JPEG2000's use of wavelet compression, which isn't mentioned at all.
I've been involved in JPEG 2000 for a while now, and come to the conclusion that..
:).
:) karma in offtopics.
A) It's an excellent codec, though computationally heavy
B) The design of the codestream along with JP2/JPX file format has a lot of potential to create a "new" type of image that isn't just a picture. Yes, you've heard this before, but this time it's built in at a codec level. In stream ROI's, very flexible reconstruction and compression controllable through great numbers of options - and that's only the codec (at a *very* rudimentary level
C) It won't succeed without a decent opensource, "IPR free" (as much as is possible) implementation.
D) Read C again. It's important
To this end, I've started (with support from others in the JPEG 2000 community), a JPEG 2000 Group (See http://www.j2g.org - It's very sparse at the moment, but if you're interested, bookmark it and come back in about a month). Tom Lane and IGJ have expressed no interested in JPEG2000, for various reasons (which I don't entirely disagree with, but I'd rather be proactive and try to correct flaws than walk away totally).
The aims of the JPEG 2000 Group are to create a public, open source (probably BSD license) implementation of "Part 1" (This is the codestream syntax, codec, and file format wrapper). We'll also provide a community JPEG 2000 resource. To facilitate this, we've already attained a Class C liaison with the committee. This grants all members the option of acquiring the standard free of charge. We also get a minimal channel back into the process to give opinions.
The point of this ever rambling post is this : We need members. The standard is large, and the support around it will be larger. We need volunteers who would be interested in assisting in the creation of the codec. Sadly, "Membership" is going to require some form of contribution and commitment to acquire copies of the texts you'll need - I hate this as much as you, but it was accept it, or don't get any copies at all (without $$$). If you're interested in contributing in any way (code, documents, testing, support), please drop by the at forum - Even if its only a passing interest, I'd be happy to go into more detail regarding the project (or just JPEG 2000 itself). I'd do it here, but I'd loose all my (low
So, rather than bitch about the lack of a free implementation and how late it is, and how it'll never get used, come and help out! You know you (might possibly | maybe | someday) want to!
Everyone is still using old formats like GIF and JPEG.
But there are other, more powerful formats.
For a non-descructive compression, the PNG format is fortunately getting more and more popular, although the late inclusion in Internet Explorer slows down its wide adoption.
But when it comes to a destructive compression, there's an excellent (and not new) format made by AT&T and called DjVu. It was one of the first wavelets-based format.
DjVu is really better than Jpeg. Images are better looking (more contrast, less pixels with odd colors), and files are way smaller. Plus you can smoothly zoom any DjVu image without getting big and ugly blocks.
DjVu has been available for a while as a plugin for common browsers.
There's a 100% free implementation of the format called DjVuLibre .
However, nobody uses it. I don't understand why. Some times ago, it may have been because compression was slow. But nowadays, it's no more a valid point.
People are enthusiast for Jpeg2000. But why would Jpeg2000 be adopted while DjVu has never been?
{{.sig}}
The major blocker for PNG is the fact that IE does not support its alpha channel. I originally used PNGs with alpha channels on a web site I made, but then had to replace them when I found out IE didn't support the alpha channel. This was a pain in the arse because the end result looks a tad crappy.
I thought this was a good comparasion between JPEG and JPEG2000.
Good one. Thanks for the link.
Looks like JPEG2000 finally got things right for the human eye:
- Higher compression ratios just gently blur details, rather than creating artifacts. Losing the extra information leaves the part that DID get through intact.
- The text says the compression allows for progressive downloading. This implies that the coding scheme does something like working upward in spatial frequency - encoding the basic stuff first then sending progressively finer deltas. For a given compression ratio just stop the downloading (or file saving) when you have enough.
- The compression seems to match eye processing so well that highly compressed (100:1) images actually look BETTER than the basic image. The features important to the eye (facial stuff, especially eyes) gets through or even enhanced, while unnecessary detail - including sampling artifacts - gets selectively blurred out. Something like the soft-focus filter in portrait photography. The only thing in the samples that got noticably worse at high-compression is hair, which just gets a bit blurry. (Meanwhile, JPEG looked like it had pixelated measles.)
Of course the images selected for the demo could have been optimized for the compression scheme. B-)
Bantam Dominique roosters crow a four-note song. Once you've heard it as "Happy BIRTHday" you can't NOT hear it that way
I hope they have added a metadata section where data like author, date, etc could be attached internally to the image.
I always thought it would be cool if your digital camera could include the settings (fstop, exposure time, ISO, etc, compression ratio) along with data, time and author directly in the image file.
Here's a summary of the jpeg2000 situation that I wrote up, but never made it into bugzilla: