Talk:JPEG 2000

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Comparison to JPEG-LS[edit]

Seems like there should be a section on this (not just split between Advantages and Disadvantage. It is part of the historical development of JPEG of which J2K is a later format. It should talk about WHY it was proposed after it had developed JPEG-LS, in other words the comparison to original JPEG is somewhat false. Maybe the article also needs a history section (although maybe this should be first added in the article on the Joint Photographic Experts Group). —Preceding unsigned comment added by (talk) 16:30, 10 January 2010 (UTC)


The article states in the references that the final standard is not available freely. I think this might be wrong. As the JPEG consortium is a group of ISO and ITU-T all standards get published on the ITU-T pages as "Technical Recommendations". See T.800 to T.812 for the JPEG 2000 standards. —Preceding unsigned comment added by (talk) 13:39, 20 July 2008 (UTC)


The article mentions that 'editability' is a feature of JPEG 2000, but does not explain. If I knew anything about this, I'd fix it.

This is likely referring to the fact that JPEG is lossy compression only, so every time you edit it it loses fidelity (loses information every time you safe). Eventually the image is degraded terribly. JPEG2000 has lossless compression as an option. This means you could make changes to the file, and save it without losing fidelity over time. For this reason lossless image formats are better than lossy ones. However, they take up more space (all that information that you'd otherwise get to throw away in a lossy format). So there is a pro and a con to lossless formats. JPEG on its own is best used as a one shot conversion from a lossless format in a read-only sense, like for distributing on the web where you don't care about editablity but do care about small images. JPEG2000 however is capable of making even smaller images with the same apparent visual quality as JPEG. So JPEG2000 beats JPEG in this area as well. Where JPEG is better is that more devices support it, and it takes less computing resources to decompress. I'd edit the article myself but I hate wikipedia. — Preceding unsigned comment added by (talk) 05:12, 5 August 2016 (UTC)


Right now the article looks like it was written by some JPEG 2000 promotion group, with the first section being "Superiority of JPEG2000". I chuckled when I saw that. I think this should be renamed "Advantages" and another section with "Disadvantages" created right below. Disadvantages possibly being slower compression/decompression (not so good for digital cameras with limited processing power), patent issus (mentioned at the end of the article), lack of support and very slow adaptation, and that images that are "good enough quality" with no visible artifacts are pretty much same size with JPEG and JPEG2000. At least in my tests JPEG2000 seems to win only with quality that clearly shows some noticeable artifacts; It's just that JPEG then shows more. So it's questionable if the format is all that useful, as images with no visual artifacts are usually desirable (and not that big either). Magnus below at Test-Image-section also said something that confirms my observations: "But I think that JPEG2000 isn't better than JPEG at higger queality, it smooths more de image and deletes some detail that JPEG show it." At some compression ratio for some images, JPEG2000 may indeed look worse for the same file size. Negleting to mention this in the article is just hiding the facts. Also in my experience, lossless JPEG2000 is worse than PNG (compressed with pngcrush) even for photos, not just diagrams as the article suggests.

But I didn't edit the article because my info may be wrong or old. Someone better informed should do it if she seems it as appropriate.

There sure should be a section on disadvantages. I tried out JPEG 2000 a bit. And well, the disadvantages outweigh the advantages. First of all, although it eliminates the "jpeg artifacts", it smooths the image too much. A #8 compression on jpeg 2000 is a much larger files size than a #8 regular jpeg, and if compensated to match file size, the regular jpeg preserves more detail. And anyway, hardly any applications support jpeg 2000, so what's the use? Althepal 03:27, 8 January 2007 (UTC)

I wonder if it would be okay to insert into the article criticism that isn't backed by any notable publication. I too find J2K disappointing. The only thing it might do better than JPEG is extreme compression (say 1/50), and that's not what most people are after. The only general use for it I can think of is lossless photos compression that compresses better than PNG and is somewhat compatible. But that isn't too promising considering JPEG-LS almost always compresses better and always requires much less horsepower. Maybe the situation could be better with better encoders (and maybe they have improved sincen I last tested)?

So what do you reckon, should this be added in? ehudshapira 06:26, 17 June 2007 (UTC)

User ehudshapira wrote: The only thing it might do better than JPEG is extreme compression (say 1/50).

My reply: If you simply feed an image into JPEG 1991 and JPEG 2000 and do extreme compression on it, JPEG 2000 will definitely come out looking better. However, for extreme compression JPEG 1991 is just about as good as JPEG 2000 if you do things as follows in the 1991 compressor. First the compressor reduces the image size -- by a factor of two for each of horizontal and vertical, for instance. Then the smaller image is compressed in the ordinary JPEG 1991 way. Later, the decompressor decompresses it in the ordinary way, and then the image is zoomed back up by the factor of whatever it was reduced by. The consequence of reducing and re-expanding it is an image that suffers from some blurring artefacts. The re-expansion is done by interpolation. Blurring is not as objectionable to the human eye as the texas chain-saw massacre of blocking and ringing that happens in JPEG 1991 when you do extreme compression on it. What JPEG 2000 produces under extreme compression is a blurry image and it does so by reducing the image's resolution, which is the same thing as reducing the size. The 1991 standard doesn't include the feature of reducing and re-expanding for extreme compression. User sean 20:36, 5 July 2007 (UTC)



Perhaps, somebody can work it into the article. 20:58, 1 January 2006 (UTC)

It's an interesting test image; it has been saved at 20% quality (6.9kb), and the JPEG2000 image has been saved with the same file size.
But I think JPEG2000 isn't better than JPEG at higher quality. It smooths more of the image and deletes some detail that JPEG would show.
I have found another comparison with some levels of compression with the Lura Wave plugin for Irfanview :[1] and these are the results:
Images in EMBED tag (browsers with a JPEG2000 plugin)
Images in IMG tag (browsers with naive JPEG2000 support, as Konqueror)
The frist table are images without colour subsamplig (4:4:4), and the second with a 4:2:2 subsamplig.
Sorry if my English is very poor.
--Magnus Colossus 16:08, 16 February 2006 (UTC)
i demand lena. 00:40, 27 July 2006 (UTC)

JPEG/JPEG 2000 comparision with JPEG images?[edit]

I don't understand why the test images provided here try to show the differences between JPEG and JPEG 2000 by showing them next to each other on a JPEG image. This is like comparing CD quality sound and HD quality sound by copying both of them on a Audio CD... --Abdull 21:01, 12 June 2006 (UTC)

I just came here to say the same thing. They took a JPEG 2000, turned up the loss, and then to show it to people on Wikipedia, they re-compressed it as a JPEG? If the final JPEG as saved at really high quality settings, then it's not as bad as the recording example given above, but it is still NOT VALID. It can NOT be a fair comparsson of the artifacts of JPEG-2000 vs JPEG when they're both a JPEG! It needs to be something lossless. I assume PNG is the most widely supported by web browsers?

Fixed. I hope you like the new image. --Shlomi Tal 18:45, 24 June 2006 (UTC)

Is it possible, that the images of the JPEG/JPEG 2000 comparison have been mixed up? It's obvious, that the doggie's picture called "JPEG" looks way sharper and shows much more detail than the JPEG 2000 picture. I don't really know JPEG 2000 from own experiences, but wasn't it intended to be superior compared to JPEG? Regards, Elmario —Preceding unsigned comment added by (talk) 04:41, 9 August 2009 (UTC)

They haven't been mixed up: if you zoom into the JPEG one, you will see JPEG artifacts (8x8 blocks), but if you zoom into the JPEG 2000 one, you will see that it looks completely different. It's not surprising that the JPEG one looks sharper, since bluriness is a JPEG 2000 artifact. --Zundark (talk) 08:52, 9 August 2009 (UTC)

Section on Techical Discussion[edit]

I've read the techinal description section, and I think it can be re-written a fair bit. In particular, the description can be organized much better, and the rich feature set offered by J2K can be made more explicit (eg: the progressive nature of the code-stream, compressed domain manipulations, and so on).

I'll probably be able to do this in a little while - but since I'm new to editing Wiki, I thought I'd make a post first and get people's opinions on this before I did anything substantial.

--Brokentooth 22:21, 20 July 2006 (UTC)

I don't know how to use WIKI, but its stated that wavelet compression is more computationally intensive than regular jpeg. This is simply not true, wavelets are FAST/simple TRANSFORMATIONS!! compared to DCT based transforms.

Jpeg2000's ability to store lossless images is an important difference, as well as its support for higher colour bitdepth.
Also its a ability to perform partial/resolution decompression is important. The FBI use a wavelet image format just for this reason, so that finger print databases can be analysed quickly. Ronx  —Preceding unsigned comment added by (talk) 04:58, 23 May 2009 (UTC) 

Section on Coding in Technical Discussion[edit]

The section about layers and packets is confused. Layers are not groups of packets, packets are groups of layers. See "JPEG 2000 Part I Final Committee Draft Version 1.0" (ISO/IEC JTC 1/SC 29/WG 1 N1646R) Page 61, Annex B.8 Packets.

-- Emily

Free software[edit]

Regardless, however, of the monetary cost of licensing JPEG2000 patents, it would still be impossible to comply with the Debian Free Software Guidelines (the acid test of software freedom) with freely-licensed patents unless the licenses were redistributable and irrevocable, even if the licensed application is modified. This alone could hamper adoption of JPEG 2000 for web purposes as it would exclude open-source web browsers (most notably Gecko-based browsers) and popular LAMP web applications.
I know very little about free software licensing in general, but surely it could be implemented in a library with free software compatible license (even tho the license itself obviously wouldn't be a free software license) and therefore included as a non free software portion of a free software application. Non free software proponents may not want to do this, but it sounds to me like this is suggesting it's not possible to have JPEG2000 support in freesoftware which I'm pretty sure isn't true. Besides that can't you write the source code even if you can't distribute the binaries? Isn't this how XviD works? Also, VLC seems to have survived despite including support for the patented XviD...? Not to mention GIF was supported while it was patented. I understand why free software proponents dislike (or hate) patents, but I feel the current wording is misleading as it appears to suggest patents must be a deathnell Nil Einne 15:12, 11 January 2007 (UTC)

Yes, Debian can put software in the non-free section when it doesn't meet the DFSG, and has before.

Legal Issues[edit]

I wanted to bring this up because doing a patent search on "wavelet transform" and "wavelet image" seems to bring up many patents, possibly around 500 or so. So the statement about the heavily patented area seems to be true on it's face although there's not a study or a white paper to point to. Just a patent search will bring the facts to light.

this phrase: "JPEG 2000 is not widely supported in present software due to the perceived danger of software patents on the mathematics of the compression method, this area of mathematics being heavily patented in general[citation needed]."

is invalid. Do it based on any research?

"perceived danger of software patents " can't be the reason of not widely support. The work processed to clean up JPEG2000 standart from submarine patents is a lot bigger than for example JPEG or GIF. But JPEG and GIF is more sphread now. So this assumption on reason of "not widely supported " must be removed ASAP, it is just lie.

You can argue about whether there's a "danger of patents" or not, but there is obviously a *perceived* danger. I came here looking for the reasons why W3C rejected jpeg2000. IIRC it was due to perceived patent danger. Anyone got info on this? Gronky (talk) 16:15, 18 February 2009 (UTC)

Please point me to the fact that "W3C rejected jpeg2000" —Preceding unsigned comment added by (talk) 16:20, 5 March 2009 (UTC)

is there any fact for this "Because of this statement, controversy remains in the software community concerning the legal status of the JPEG2000 standard." ? Looks like it is somebody's opinion. —Preceding unsigned comment added by (talk) 16:23, 5 March 2009 (UTC)

"JPEG 2000 is included in most Linux distributions."[edit]

What is this supposed to mean? AnonMoos 03:03, 5 October 2007 (UTC)

I think it means that most Linux distributions SUPPORT it as a standard. Inclusivedisjunction (talk) 07:01, 19 January 2008 (UTC)

Well, what does that mean, then? Debian Linux has the libopenjpeg2 package, but only eight other packages use it, only two of them are actual applications, and only one of the two (krita) deals with normal bitmapped images. In other words, AFAICT virtually no applications can show or save JPEG 2000 images. /JöG (talk) 21:08, 28 November 2012 (UTC)

Just a clarification: ImageMagick and GraphicsMagick are able to display and save JPEG 2000 files. Ubuntu can show JPEG 2000 in the thumbnails and is able to open them. --Cantalamessa (talk) 14:32, 29 November 2012 (UTC)

machine judgment of quality[edit]

Images machine-judged to be of equivalent quality for both compression schemes often look better to humans in JPEG 2000 at low bitrates.

I am removing the above because all it means is "A certain machine test of image quality doesn't work". If humans judge that one image is better quality than another, then a working metric will give them different scores. The whole purpose of such a metric is to predict human judgment of quality. TomViza 19:48, 4 November 2007 (UTC)

Article cleanup[edit]

The tone, partiality, article structure, and difficult readability all need to be addressed. The article is not only extremely technical it is addressing the perceived advantages of JPEG2000. Non-technical users will not understand this article even at the introduction. It needs the more technical bits moved to another section and a gentle introduction, history, and body copy must be written. --KJRehberg (talk) 05:07, 17 January 2008 (UTC)

What is the perf difference?[edit]

The article makes it sound like the encoding and decoding performance is significant, but I see no hard numbers. I looked for them on the web, and couldn't find any either. If someone has some speed and/or memory numbers, it would be nice to add, because this article has the important numbers in many other places. KeithCu (talk) 10:17, 15 March 2008 (UTC)


It seems a bit silly to me to feature thumbnails of comparisons, since at low resolution all three versions are indistinguishable. Of course they can click on the images for a larger image, but it's preferable to be able to see the artifacts alongside the explanatory text. I'd suggest creating an actual thumbnail-sized demonstration image, and making the image somewhat bigger (e.g. 300px wide). Dcoetzee 06:15, 6 August 2008 (UTC)

Comparison w/ Mr. Sid?[edit]

As I understand it, Mr. Sid (.SID from Lizard Tech) is still the industry standard for compressing geospatial imagery but I see no mention of this format. JPeg 2000 is the new kid on the block. —Preceding unsigned comment added by (talk) 21:37, 10 October 2008 (UTC)

Basic (Part1) and Advanced (Part2)[edit]

Applications are compared regarding their support for Part1 and Part2. Perhaps the table JPEG 2000 image coding system - Parts could be more verbose on what the Parts are about? "Extensions, (.jpx, .jpf)" is not sufficient IMHO.-- (talk) 18:07, 11 March 2010 (UTC)

Acrobat support[edit]

Having searched on the web for converters from JP2 to JPG (or anything else) and found many that are quite pricey, I've since found that Acrobat version 8 can read jp2, and this is worth noting in the table. MS Office 2007 doesn't appear to support jp2 import. (talk) 11:00, 21 April 2010 (UTC)

Illegal abbreviations[edit]

The submitted picture labels file size in "KiB". Abbreviation standards are quite clear (see for example). The only acceptable abbreviation for kilobytes is kB. Postlewaight (talk) 18:20, 6 October 2010 (UTC)

See binary prefix. --DaBler (talk) 19:29, 6 October 2010 (UTC)

Colour Transforms[edit]

In this section is the wording:

"This step is called multiple component transformation in the JPEG 2000 language since its usage is not restricted to the RGB color model."

Typically chrominance subsampling is applied in YCbCr images because the Cb and Cr (i.e. Chrominance) are separate. I think the correct wording should be "... since its usage is not restricted to the YCbCr color model". Although it is in the standard, I don't really see how you would get benefit from applying it to RGB space. If someone more familiar with JPEG 2000 could explain, it would improve the article. — Preceding unsigned comment added by (talk) 15:00, 2 January 2012 (UTC)


In the Tiling section it says:

"The disadvantage of this approach is that the quality of the picture decreases due to a lower peak signal-to-noise ratio."

PSNR is a measurement of the quality therefore this statement is saying "It's bad because the results are not good". I would expect tiling to be a trade off between 1. dividing the image into more manageable chunks and 2. introducing more chunks adds overhead in the case of a fixed bit rate budget. — Preceding unsigned comment added by (talk) 15:04, 2 January 2012 (UTC)

Sample image?[edit]

Shouldn't wikipedia actually provide a .jp2 image for people to view (even if most browsers would still show the "broken image" symbol)? There doesn't actually seem to be a Jpeg-2000 format file anywhere in the article or the links! — Preceding unsigned comment added by (talk) 00:13, 28 April 2012 (UTC)

It couldn't be hosted at the moment, it is an unsupported file type. A repository of weird media formats for quick tests would be nice. Check out Mplayer, I vaguely recall that they have lots of test files. – (talk) 22:31, 21 January 2014 (UTC)

best of jpeg for photo graph[edit]

I have a PSD file that is full quality but when I try to save it as a JPG file, the quality is a little bit less. What I want to ask you is..... how do I to save the image in JPG or JPEG or jpeg2000 format preserving the quality of the image? what format is best of foto print quality ?

pls help me  — Preceding unsigned comment added by (talk) 16:11, 9 April 2013 (UTC) 
".jpg" and ".jpeg" are just filename extensions, they both are used for JPEG, which is always lossy. JPEG 2000 is not JPEG; JPEG 2000 can be lossy or lossless. If you want to preserve the quality completely, you need a lossless format. A free lossless compression format viewable in web browsers is PNG. If you want to save image in an open format, but preserve data like layers (though not viewable in a web browser), try OpenRaster. --AVRS (talk) 16:55, 9 April 2013 (UTC)


This article uses jargon for which there is no Wikipedia entry, like "codestream" for example. A search for "codestream" on the wikipedia landed me back on this article. This is not what Wikipedia articles are supposed to be like, in my opinion. Feraudyh (talk) 17:04, 7 November 2013 (UTC)

I moved the explanation to the lead section (second paragraph.) Apparently contributors here don't agree on a spelling (codestream vs. code stream vs. code-stream). I added Video compression picture types to See also, found in a search for "code stream". – (talk) 22:22, 21 January 2014 (UTC)
The proper word is "bitstream". Kegon (talk) 13:26, 8 August 2014 (UTC)

It also used bitrate and bit rate inconsistently

Windows & Microsoft Products[edit]

It would be a huge boon for many users of Wikipedia if the article contained a simple statement to explain that all versions of Windows and Microsoft products (e.g. Office) do not appear to have any native support for JP2, and that the only way of viewing or using JP2 files is to download one of the software packages listed, so they can then view or save the file in another format as required. Stub Mandrel (talk) 20:16, 8 August 2015 (UTC)

Or just trash Windows and use GNU/Linux, which is the general solution for any such issue. ;) Nemo 11:40, 2 February 2016 (UTC)

Options for lossy compression in various implementations[edit] is very interesting, we should probably copy their page 12 table into the article. Nemo 11:39, 2 February 2016 (UTC)

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PNG is better comment[edit]

One of the sections talks about PNG being better for images with a lot of pixels of the same color as a throwaway slap in the face with no references. PNG by default can compress to many different sizes. You need to run a special optimization tool in order to find "a best" (not the best) condition under which you can compress the PNG to get near-optimal space. My own testing which has no place in a wikipedia page is in 400 dpi scans of A4 and larger sized photographs which are either mostly white or mostly black. In these cases the latest builds of libopenjpg and Photoshop itself show file sizes considerably smaller than PNG. 10% smaller in fact than PNG files that have been optimized by the minimum result of pngcrush and optipng. So my use case matches what is tossed out here in wikipedia perfectly but my results certainly do not. Sample output:

7.5M    220230001.tif ; source file, ZIP compressed greyscale mostly-black TIFF file

668K    220230001.lossy.jpf ; JPEG2000 lossy compression (Adobe Photoshop defaults)
968K    220230001.c7.jpg ; JPEG lossy compression 7
968K    220230001.c9.jpg ; JPEG lossy compression 9
5.5M    220230001.j2k ; opj_compress lossless JPEG 2000 compression
5.9M    220230001.pngopt ; (minimum size file in a contest between optipng and pngcrush)
6.1M    220230001.png ; standard PNG produced by Adobe Bridge

So, PNG in this case is a good improvement over ZIP compressed TIF, and the optimizers give a slight benefit. But J2K is much better and the lossy compression results are the best of all.

This kind of throwaway statement said with great authority is a hugely bad thing when not backed up. Someone researching file formats for an application will read something like this and then dismiss JPEG2000 as being without merit as apparently it was not designed to compete with other lossless implementations (they why did they bother making a lossless implementation if they didn't want to compete, according to wikipedia?) and it as well does not perform as well as the others. So that will be the beginning and the end for our researcher who will now move on to PNG vs. TIF. And that is bad, as wikipedia will have misled him.

Own research of course has no place on wikipedia, I only use this as a basis to insert the "citation needed" flag on the statement that PNG is simply flat out better than JPEG2000 lossless. Obviously it's not true as a sweeping statement, there are perhaps some conditions where it may be true, but this is why a citation should be used and this statement needs to be backed up. It may have just been typed in by "some dude" who likes PNG. — Preceding unsigned comment added by (talk) 05:28, 5 August 2016 (UTC)