Slashdot Mirror
Presenting APNG: Like MNG, Only Better
An anonymous reader writes "It's fair to say that most people love PNG images (or at least hate GIFs). However, the one advantage GIFs have over PNGs is that they can be animated. There is, of course, an animated version of PNG, MNG, but few programs can view these images (mainly because the MNG decoder is so large that the likes of Mozilla refuse to include it). But there may be an answer coming: Vladimir Vukicevic and Stuart 'Pavlov' Parmenter (of Mozilla fame) have put together a specification for APNG (Animated Portable Network Graphics)." (Read more below.)
"Unlike MNG, APNG is not a separate file format, but rather an extension to PNG. Thus, APNG images are just normal PNG images (with the .png extension) but can be animated. The system is fully backwards-compatable, so any program that can open a PNG image will be able to open an APNG image (though non-APNG viewers will only show the first frame). Vitally, the decoder just adds an extra few kilobytes onto a standard PNG decoder. APNG support is in the process of being checked into Mozilla. Hopefully, other programs will follow suit."
Microsoft holds the power in their hands as to what file formats become standards. Hopefully they'll make the right decision...
This is probably a stupid question, but what are animated gifs used for besides online ads? It seems to me that the animated gif is now an endangered animal found only in annoying online ads, or annoying web-pages that were put together by someone with a rudimentary knowledge of HTML and a free CD of clip-art (or images that they stole from another unattractive site). I would not be sad to see animated gifs (or apngs) disappear entirely. If someone can post a good use of apgns/gifs for which a better solution does not exist, I will humbly retract my opinion and we can all consider this to be have been, indeed, a stupid question.
Do you actualy consider Firefox bloated? Maybe I'm jaded by some of the stuff becoming so big previously that anything less seems to be lean and mean in relation..
That said, Firefox seems pretty quick to me.
I'll give you the transparency (which IE does not support on PNG without gross hacks) but GIF supports infinite colors basically, in increments of 256.
gif-with-32697-colors
Morphing Software
Why not? Alpha blending allows web developers to make fine adjustments to page layouts with necessitating the "recutting" of overlapping layers in Photoshop. It also allows for variance in browser layout without causing visible breaks -- thus Mozilla and KDE don't need to render "exactly" like MSIE down to the last pixel in order for layouts to basically look the same.
GIF is gunk. Can we step into the 21st century yet?
// I will show you fear in a handful of jellybeans.
MNG is as far as I can see the _only_ format suitable for an Amiga-DPaint-workalike in this day and age (no good one exists today except for the astronimically-priced Windows TVPaint/Mirage, and that is a direct descendant of Amiga TVPaint).
APNG looks too lightweight, missing many features necessary to replace the ancient (but still in use!) Amiga-IFF-ANIM. Sure, it's a replacement for shitty animgifs. But can it replace the Amiga-IFF-ANIM7 roughs for a feature-length cartoon?
Yes, much of the industry now uses vector animation (i.e. macromedia's stuff), but bitmapped animations are much easier to seamlessly integrate with bitmapped digitised film. Want a(nother) open source killer app? Take the cinepaint/gimp engine, add a dpaint-like interface and MNG support and lots of bitmap-animation-creation-and-editing features, and several animation companies I know can finally lose their old big-box Amiga stockpiles...
The whole reason for PNG's creation was as a response to the potential doom spelled by the enforcement of GIF patents and of course they took the opportunity to improve on the limitations of GIF as well... but was back in the day, in the very beginning, I assumed that the PNG specification would include animation as part of PNG's purpose.
I think the best answer here would be to enhance the existing PNG specification just as GIF's original specification was enhanced to include animation. Let's not call it "*.APNG" or "*.MNG" for that matter. It should still be called *".PNG" just as *.GIF always remained.
I think it would be a mistake to add to the ever-increasing number of filename extensions that exist out there. Isn't this convention a part of DOS and CP/M's legacy anyway? Filename extensions are handy information to append but only to a point.
It's a very neat trick. I remember marvelling at it the last time it came round.
It works because each frame in an animated GIF has its own palette --- but that palette doesn't have to match the palette in the other frames. So the first frame draws the first 256 colours, then the second frame draws the next, etc. The test image has been slowed down so you can see it load.
Of course, it's not actually useful --- the resulting image is far larger than, say, the PNG version --- but it's a clever hack anyway and I wish I'd thought of it...
The only thing I can think of is that the software you're using to save your PNG files must be horribly broken. It should be giving you the option to save the gamma value or not --- for what you want, you want not. The Gimp has a whole dialogue it pops up whenever you save a PNG file asking you what extra information you want to save; resolution, creation date, gamma, etc.
To remove the gamma chunk from someone else's files, try this:
...although if you've been converting them to GIFs, you've probably been editing them.
(sarcasm)You think it'll be that quick, do you?(/sarcasm)
All jokes aside, I wouldn't be so sure of that. If FireFox and Mozilla make as much inroads into the browser market as some people think it will then Microsoft will either have to pull their finger out and keep IE up-to-date and standards-compliant or drop out of the market - something I seriously doubt will happen.
FireFox is already a long way there. One department at work got so sick of the pop-up infested site they needed to use for some of their work that they demanded something be done about it. Our MIS deparment said nothing could be done until I suggested (and proofed) FireFox. Now it's a standard browser for that department and is being looked at for the rest of the organisation as well.
That makes little sense, as the DirectX filters are usable on Windows NT. The filters came out with IE 5.5. This means that the alpha-blending group must either suffered political pressure, or were just overlooking this solution when it came to real support in IE 5.5. They could (probably) easily switched the PNG handler to DirectX rather than whatever it is now without the end user really noticing or caring.
;)
That being said, I'd like to hear their excuse for not supporint <object> properly
It takes eons to load because it's an animated gif demonstrating the concept behind is (which is rather old):
:)
Each frame of the GIF can have up to 255 colours (+ transparent); but separate frames can have separate palettes. So frame #2 uses a different palette from frame #1, and so on. For real use, you can easily set the time interval between each frame to be zero (so they looks like it's done in one go).
I remember seeing another image like this - I believe it was a picture of a ship of some sort - a few years back. It was actually neater, as it was loaded 'progressively' - it first presented a 8-bit version like a normal GIF, then overlaid extra colours on top. Certainly more interesting than this demo.
It's bigger than PNG because it is limited to 8bits per pass - can't really look at how adjacent pixels have similiar (but not exactly matching) colours. Probably, anyway; I have not tried to dig deep into either GIF nor PNG
Humans have 3 types of cone cells.
Make the phosphors only excite one cone type each, and you can generate all the colors the eye can see.
Now, monitor manufacturers, listen up! We need a reasonable green that isn't yellowish. I can *so* tell the difference. I can see cerulean blue (a most lovely color - the color of some TDK CD-Rs) in real life, but not on a monitor.
Just because it CAN be done, doesn't mean it should!
Actually, from what I understand, we're least sensitive to variations in red. Which is very funny, because it's the colour our eyes are most sensitive to -- we just can't pick out subtle variations in that colour.
I hope that makes sense? sensitive to red itself, but not to the differences in various shades of red.
Standing at the very edge of my imagination, I peered into the inky void and realised -- I couldn't think up a new sig.
Make the phosphors only excite one cone type each, and you can generate all the colors the eye can see.
You are assuming that everybody's cones respond to the same wavelengths identically. That is most definitely not true. Different people's eyes respond to colors differently -- different people's cones have response curves centered at slightly different shades of red, green, and blue. In fact, some women have been found to have 4 different kinds of cones.
There are two ways to produce a perception of color. One way is to create a beam of light of the correct wavelength. A light with a wavelength between red and green would stimulate both the red and the green cones in my eye, creating the sensation of yellow. Another way is to mix multiple beams of other wavelengths. A mixture of red and green lights would also stimulate the red and green cones in my eye, creating the same sensation.
I could adjust two different beams of light (one pure yellow, one red + green) until they both appeared to me to be the same color. I would not be able to tell the difference between them. However, somebody else whose "red" cones centered on a slightly different wavelength of red would see the two beams of light to be slightly different colors.
Monitor manufacturers actually can't make everybody happy. They do their best to pick the shades of red, blue, and green that are most commonly the centers of the response curves for people's cones. If they hit the centers dead-on for you, your monitor would be able to create any color that you could see. But if your centers weren't quite dead-on, or if you were a woman with 4 different types of cones, there would be a significant range of colors that the monitor could never produce properly for you.
Time flies like an arrow. Fruit flies like a banana.
the human eye cannot distinguish between that many shades (particularly in the blue region)
While it may seem counterintuitive, the human eye is much better at discriminating between shades of blue than between red or green (where it is worst by far). There's a nice graph showing the MacAdam ellipses that represent the amount of variation in chromaticity where no difference can be percieved in this paper. This is obviously different from the responsiveness to brightness.
16 bit color representaion usually has the 6 bits for green.
For most people, 8 bit per RGB component on an linear scale, as used in almost all computers, is not enough - you can still see some banding. A logarithmic scale or 10 bit color can fix this.