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GIF Slips Away From Unisys; Your Move, IBM
Twenty years ago, Terry Welch's improvement on Lempel-Ziv compression appeared in IEEE Computer magazine. The authors of unix 'compress' and the GIF standard incorporated that algorithm without realizing it was patent-pending. When the submarine patent surfaced ten years later, its new owner Unisys intimidated developers and web authors into moving away from GIFs, inspiring the creation of a better standard, though sadly still a less popular one. Today, July 7, 2004, Unisys's last LZW patent (in Canada) expires, leaving GIF once again free... almost. See, there's the small matter of IBM's patent, granted on the same algorithm, which is valid for another two years. That still has a chilling effect on GIF development, though the consensus seems to be that IBM would lose any court action it tried to bring. So how about it, IBM? You've got nothing to lose! Want to make a lot of geeks happy and release that final patent into the public domain?
I'm not sure on the merits of the GIF format after all these years, the only thing it brings to the web expierence is flashing adverts, PNG provides full alpha-transparency which is really required for the future of web design.
Because GIF is used MUCH more, so people writing software that make use of images in general (browsers, image editors, etc.) have to deal with this patented algorithm, or risk losing users because their software doesn't support one of the most widely used formats.
"The best laid plans of mice and men gang oft agley..." - ROBERT BURNS
It's hard to do away with GIF because GIF's are animated. PNG's are not. There's the MNG standard, which is basically an animated PNG, but it isn't widely supported yet.
Quick source view of the main slashdot page shows that "gif" is found about 50 times.
"png" is found twice -- both of which are related to the original post.
Now you know why we care. The web community uses gif more than png. For better or worse...
Davak
You're talking about an obsolete technology [GIF] that nobody cares about.
I'd question that. Check Google images and see how many web sites still exclusively use .gifs. Not to mention a certain main-stream browser whose support for .pngs is still patchy.
I guess you and I have different definitions of "obsolete".
This is where the serious fun begins.
You can't make animations with PNG files....
Sure you can, only the result is called MNG.
Belief is the currency of delusion.
Indeed, the web would be much more beautiful if IE supported alpha transparency in PNGs.
Sticking feathers up your butt does not make you a chicken - Tyler Durden
The original Welch paper is pretty readable:
Terry A. Welch, "A Technique for High Performance Data Compression", IEEE Computer, Vol. 17, No. 6, 1984, pp. 8-19.
If you don't want to go to a library and look that up, then Google will find you about 12000 hits on "Welch LZW", and the first few all seem to be exactly what you want.
the whole ruckus was because they did publish the algorithm widely and it got used widely - and only then did they reveal their submarine.
the algo is/was very widely known.
world was created 5 seconds before this post as it is.
Actually that patent is being used in IBM's (second amended) counterclaims in the SCO v IBM case.
JeR
bloating their sites with transparent effects where it is not needed.
Every once in a while somebody seems to open their mouth without realizing they have no clue what they are talking about.
How exactly is a transparent image bloat? I did a test. As a gif a logo I have is 3.32K without alpha and 3.33K with alpha. A PNG (both regular and alpha) it was 3.45K. That should dispel both the claims that PNG is bigger and that transparency adds bloat.
And what do you do everytime you change a websites background color? Change the image?
Except the browsers all support PNG (minus alpha, but GIF and JPG don't have that anyway), where as most MP3 players can't play Vorbis..
...MNG code is not very good to begin with, I believe MNG support was ditched from Mozilla as well, which makes it supported in approximately 0% of the web browsers out there.
I use PNG quite a bit, but mainly as a competitor to TIF files, but I do prefer to use PNG over GIF in websites too. However, I'm only using non-transparent, plain PNGs for maximum compatibility.
Animated GIFs? Oh, right. I turned those off, along with pop-ups. If I wanted that, I'd actually use flash or something like that. I figure either you don't block stuff (which means GIF + flash) or you block stuff, in which case you don't see either. Either way, I don't see much room for GIF files...
Kjella
Live today, because you never know what tomorrow brings
GIF is pronounced JIF.
.GIF files are pronounced JIF
Bob Berry, the developer of CompuShow for CompuServe (remember them - the people that invented the GIF format?) included with it an animated GIF89 format file that had a picture of him. It had a speach bubble with him saying:
Oh, incidentally, it's pronounced "JIF"
A quick google later and I've found a web site which has this, and other evidence that
http://www.olsenhome.com/gif/
Thanks for playing
Exactly. I'm not a full-time web developer, so I don't even think on these issues too hard most of the time. Recently I had to write a little network-monitoring app. I coded the output in standards-compliant XHTML 1.1, standards-compliant CSS for styling stuff, and I used PNGs with transparent backgrounds for certain little icons. I only tested my app in Firefox (yeah, my mistake). Later someone who actually uses IE tried to use my little web app, and found gray background squares around all my supposedly transparent-backgrounded images. Sucked. Now I know what all you web developers already knew - I have to put a background color on these pngs which matches the background they're placed on that I specified in my stylesheet. How redundant and stupid.
11*43+456^2
PNG transparency works just fine in Internet Explorer. It's just a pain in the ass.
This website will tell you how to turn it on. You can see it working on my website.
No idea why it's not on by default, but if it works...
Just to set the record straight:
When I led the process of drafting the PNG specification, GIF animation did not yet exist. Animation was not part of the original GIF specification. The GIF89a specification *did* offer a mechanism for including multiple images in a single file, and a very basic (but, in retrospect, effective) mechanism for replacing only a specified part of the preceding image. But whether this was supposed to be animation with a time component was never defined, and there was in fact no way to specify how long each frame was supposed to appear, probably because the real intent was to be able to compose a single final still image from many sections. Multiple image GIFs were a footnote to the GIF specification which hardly anybody used until Netscape stepped in.
Netscape's animated GIF format was a clever hack on top of this: they defined a new GIF chunk to specify the pause between frames.
Here's the kicker: Netscape was repeatedly invited to participate in the PNG design process. They had someone reading the list, I gather, but they never offered any suggestions or contributions. If they had, they would likely have been considered very seriously.
But instead, the first we heard of GIF animation was its public release in Netscape (2.0 beta, if I recall correctly). They could have contributed to the design of a PNG or MNG that did include animation and, by way of that compelling feature, would have been more likely to quickly replace GIF. But they didn't.
We (the PNG designers) did consider retrofitting animation into PNG when Netscape's animated GIF appeared. In fact, I lobbied for that at one point. Unfortunately we had already finalized the functional specification and there was no hope of reaching agreement on how to "jam in" the animation feature at the last minute on top of an otherwise pretty elegant image format.
Instead, the MNG group was formed to create a specification for a powerful lossless animation format. And they succeeded -- but MNG has yet to really catch fire, and animated vector formats like SWF and SVG are gradually replacing animated GIF anyway for most purposes. At the end of the day, lossless bitmap animation is a pretty bandwidth-intensive proposition.
Check out the Apostrophe open-source CMS: http://www.apostrophenow.com/
See http://www.daltonlp.com/daltonlp.cgi?item_type=1&i tem_id=217 for how to get pngs to display transparency on IE 5.5 and IE 6. This is now a well-known technique that works pretty well universally. Combine with CSS or javascript and you should be able to use pngs entirely.
No. JPEG at max quality looks perfect to the human eye, but it still has differences from the original image. Lossy compression should be avoided in situations where images are going to be decoded and recoded many times, as these errors build up to the point where they can become noticeable.
Also: make sure your PNG encoder is configured correctly. In most cases you want to be using the 'adaptive' filter.
I'll bite.
...) changes an image in such a way that humans don't percieve the difference, but it can be stored more efficiently. At lower qualities, you will begin to notice some artifacts. It can go all the way down to a completely useless collection of pixels. It's a common misconception that 100% quality JPEG images are not distorted in any way. I don't know what 100% means, other than the lowest compression your encoder supports.
JPEG, like MPEG (and Vorbis, Theora,
PNG images, on the other hand, encode the image exactly as it looks. Basically, a PNG image is a collection of pixels, some metadata, optionally compressed with deflate (same algorithm used by gzip).
JPEG images are the better choice for photograpic images (which is what they are intended for), where the exact pixel colors don't matter that much. PNG is better for line drawings, text, high contrast images; basically anything that doesn't bear slight changes to the colors. For large images, JPEG can be significantly smaller, making the case for using JPEG for screen dumps and such.
Please correct me if I got my facts wrong.
If you would like to get MNG back into Mozilla, then you can follow/vote/contribute to Bugzilla bug 18574
http://bugzilla.mozilla.org/show_bug.cgi?id=1857 4
(Please don't post useless comments on that bug)
MOD THE CHILD UP!