Talk:APNG/Archive 1

Compression Techniques?
So far it seems like APNG just slaps frames on top of each other, even if there is very little change resulting in very big animations. Even GIF seems much more advanced than that. Could someone say something about the compression techniques available for this format? Maybe it's just the editors at the moment that do not utilize any compression. Thanks. 84.129.162.224 (talk) —Preceding undated comment added 12:22, 28 August 2009 (UTC).


 * Your suspicions are correct: APNG cannot take advantage of similarities between frames. OTOH, PNG has fairly good compression of the frames, which does help a little bit. I guess good APNG editors will use something like pngcrush to minimize file sizes. Hope this helps, CWC 17:48, 28 August 2009 (UTC)


 * Thanks a lot! I do not see however, how this format can be seriously discussed as being the much-needed successor to GIF if it easily creates such big files. Thanks again. 84.129.162.224 (talk) —Preceding undated comment added 21:33, 28 August 2009 (UTC).

aMSN animated PNGs
The onensource MSN client aMSN seem to store animated GIF custom icons as animated PNG files, which work not just in Mozilla and Opera, but Safari. Haven't tried IE, as I'm on a Mac. But Safari/Webkit doesn't play the other APNG examples, and no graphics editor complain about the file being a misnamed GIF. They just open the first frame. Msandersen (talk) 14:47, 4 February 2009 (UTC)
 * um, had a look at one of these "png" files using Irfanview (via Wine). It opens and animates the file, it's usually quick to tell you of mislabeled files. Using HEX view however, the header clearly labels it as GIF89a. Info for that matter identifies it as GIF as well. Strange. Msandersen (talk) 14:59, 4 February 2009 (UTC)

Neutrality
This isn't really neutral. It's biased towards MNG - in particular, the last line makes it sound like MNG-VLC is a smaller format than APNG. Secondly, it's been established that AMNG's multiple-image format doesn't violate the PNG standard and there has been no clarification of the PNG standard since to specify that only a single image is ever allowed.

A comment about the origin of animated GIF as a similar kind of extension to the GIF specification should be added too.

Thumper 00:02, 23 December 2005 (UTC)


 * Comment about origin added ... eventually. CWC 17:48, 28 August 2009 (UTC)

Example
An example .apng would be nice. Ragzouken 16:47, 18 March 2006 (UTC)


 * How about this? http://people.mozilla.com/~dolske/blogimg/spinfox.png
 * Soulsbane 19:14, 31 October 2007 (UTC)


 * It looks nice; what's its copyright status? Foobaz·o&lt; 22:04, 31 October 2007 (UTC)


 * (C) Mozilla, all rights reserved. Were Justin Dolske not a Mozilla employee, he'd probably be due a DMCA letter. Bah. Chris Cunningham 11:22, 1 November 2007 (UTC)
 * Added a PD image found from --JDSC (talk) 09:38, 15 February 2008 (UTC)

Dates
Some dates would be nice, too. When did this file format come out? Has it even come out yet? chad. 00:19, 17 January 2007 (UTC)


 * I added a history section. If anything you're curious about is still missing, please consider adding it yourself. Foobaz&middot;o&lt; 17:35, 18 January 2007 (UTC)


 * Support in Mozilla was landed 2007-03-20, see https://bugzilla.mozilla.org/show_bug.cgi?id=257197#c102 Dolphinling 04:11, 21 March 2007 (UTC)


 * Added their support in Gran Paradiso alpha3. Does any other browser support APNG? Konqueror, maybe? MahangaTalk to me 01:46, 24 March 2007 (UTC)

MNG
MNG is too big and complex, especially with the JNG stuff in it and the delta movements. A simple format to store different frames behind each other would be perfect and APNG seems to be that. Shame that it keeps getting rejected.84.192.164.151 15:47, 10 June 2007 (UTC)

Difference with MNG?
What is, on the techinical side, the difference with MNG? Are frames stored differently? Is there a difference in supported features? Shinobu 01:14, 13 August 2007 (UTC)
 * APNGs are just sequences of frames. MNG is a full-featured system for animated images. For example, it provides moving, animated sprites and fancy looping. In the hands of an expert, MNG can do very complex animations with very small files. Unfortunately, not many people (and even fewer programs) are expert enough to get good results with MNG. So MNG has never really caught on, sadly. CWC 17:48, 28 August 2009 (UTC)

Links
Could a link be added for "getting or retrieving APNG"? —Preceding unsigned comment added by 80.108.103.172 (talk) 11:50, 9 January 2008 (UTC)

Example Animations
I feel all 3 animations on this page are moving way too fast. They make it very hard to concentrate on the text. I vote for making them a lot slower. Zalumon (talk) 20:34, 2 July 2008 (UTC)

Technical details meta line
Hi Chris, I think it is kind of important to point out that the first few paragraphs of the technical details section describe the PNG format (and not APNG). Maybe a different formulation? Zalumon (talk) 16:19, 6 July 2008 (UTC)


 * I'm sure there's a better way of doing it. My primary concern at the moment is rewriting the section so that it describes rather than teaches, and that's going to take a while. Chris Cunningham (not at work) - talk 20:33, 6 July 2008 (UTC)


 * I'm sorry to hear. You kind of make it sound as if I burdened you with unwantend work. I find it difficult to draw a clear line between describing and teaching, as you put it. I feel the average visitor would appreciate a somewhat informal introduction, since the (very) formal description is already available in form of the specs. Zalumon (talk) 16:39, 7 July 2008 (UTC)


 * Please don't feel like I don't appreciate the work you've done. I'm sure that we can find a compromise which allows the information to presented in a way which is both accessible and descriptive. Chris Cunningham (not at work) - talk 16:47, 7 July 2008 (UTC)


 * Thanks for saying so. I mean I'm glad somebody actually cares about the stuff I wrote - I was just put off by the fact that my first contribution was deemed non-descriptive. I was hoping you were going to elaborate on your understanding of descriptive and accessible. But of course I can just wait for your edits and take it from there... [off topic: I can't find any email notification settings - is there a mechanism other than manually checking up on the watchlist every few hours?]. Zalumon (talk) 18:51, 7 July 2008 (UTC)


 * The material's excellent - sorry about the response. My main role here is copy-editing as opposed to content creation, so I'm prone to looking at articles like that. At some point I hope to write up exactly what it is I do when I look at improving articles. :) Erm, yeah, anyway - I don't think there's an inbuilt facility for getting all watched changes mailed, but you could try asking on village pump (technical), which is the primary discussion forum for such stuff. Chris Cunningham (not at work) - talk 22:55, 7 July 2008 (UTC)

Spinning Firefox Logo
I feel that there could be an example that is just as good without advertising Firefox. This is not an article about Firefox, and there are other browsers that are APNG-compatible. It could be misleading to readers. 74.65.42.5 (talk) 21:06, 1 August 2008 (UTC)


 * I agree with this. Also, there's no section comparing APNG with GIF, so comparison images like this currently don't belong anywhere. They should probably be removed. CountingPine (talk) 00:30, 3 August 2008 (UTC)


 * Also, I'd like to add that the two Firefox animations aren't comparable; the APNG is a slower animation so it appears to be smoother, while the GIF is faster and 'choppy'. This is not the fault of the GIF format, but of the creator of the animation. 74.65.42.5 (talk) 21:15, 19 August 2008 (UTC)

What happens to the PLTE and ancillary chunks?
It is difficult to believe that an animation can be rendered from a sequence of *.png images without somehow including all the information generated by the png encoder. This information is not given here nor can I find it in the standard. Am I to include all the chunks other than IHDR and IEND in fDAT or am I restricted to only including the IDAT chunk in fDAT as is given both here and in the standard?

All comments welcomePuffingbilly (talk) 14:15, 29 November 2009 (UTC) I give below a snippet I received by another route -- Comment #170 from Glenn Randers-Pehrson

PLTE and ancillary chunk data is inherited from the default image by all subsequent images. See the paragraph about the fdAT chunk in the APNG spec, which includes this: "Each frame inherits every property specified by any critical or ancillary chunks before the first `IDAT` in the file, except the width and height, which come from the `fcTL` chunk."

188.221.88.48 (talk) 14:01, 30 November 2009 (UTC)

What happens to CRC fields?
To quote the standard "fDAT has the same structure as an IDAT chunk ,except that it is preceded by a sequence number."

This should modify the CRC, does it? is the CRC ignored, deleted or recalculated. In all cases?

All comments appreciated.Puffingbilly (talk) 14:34, 29 November 2009 (UTC) The following snippet was received by another route:

--- Comment #170 from Glenn Randers-Pehrson

If you change the contents of a chunk you must recalculate a new CRC for that chunk, if you want the modified datastream to be a valid PNG. See ISO PNG spec, Clause 5.3.

Thankyou.Puffingbilly (talk) 14:08, 30 November 2009 (UTC)

Is the Opera 9.5 release date correct in this article?
I think Opera 9.5 was released June 12, 2008. Not in September. —Preceding unsigned comment added by Laststop (talk • contribs) 07:10, 18 January 2010 (UTC)

Web browser contradiction
The infobox has an example animation with a caption that says: "requires recent versions of common web browsers". There is a link to a section that says: "Web browsers which do not support APNG: Internet Explorer, Safari and other WebKit-based browsers such as Google Chrome or Chromium". How are these browsers not common? It should say "if you can see the animation, you have an APNG-compatible browser " instead 83.209.89.69 (talk) 00:41, 27 February 2010 (UTC)
 * Good point. I've changed the caption to   An animated PNG (displays as static image in some web browsers) but I'm sure there's a better wording. CWC 02:28, 27 February 2010 (UTC)

Microsoft Connect Link
Does anybody have the info given in the Microsoft Connect Link? Are they anywhere online in the web without a registration? mabdul 17:22, 30 March 2010 (UTC)


 * That link is dead. I found a version of the page in Google's cache but Microsoft's reply there is very vague. Bah. (I seem to remember something much more informative.) We probably should replace that ref with a citation needed tag. Does anyone have a good source? Maybe one of the IE team has blogged about APNG? CWC 04:40, 1 April 2010 (UTC)

SVG is NOT an alternative
Please, stop comparing raster formats with vector formats. SVG can be an alternative to Flash or Silverlight, but is not an alternative to a raster format (even if it can show raster). Flash can also show raster, and it's not an alternative to GIF. We're talking raster animation formats here, and there are only 3 contenders: GIF, APNG and MNG. Damianvila (talk) 13:16, 7 January 2012 (UTC)


 * Well, in a browser which supports SVG animations, you can display a sequence of raster images ...but each image will be fetched separately. That is, with APNG or MNG you have one file fetched with one HTTP GET, but with SVG you need N+1 files (the SVG itself, plus N image files) and N+1 HTTP GET operations. So SVG is not very competitive here.
 * While I'm here, thanks for this edit, Damianvila. The article is now much better, IMO. Cheers, CWC 15:41, 7 January 2012 (UTC)


 * It's an alternative to animated images, wether or not it's a raster format shouldn't matter. --Benimation (talk) 22:45, 24 January 2015 (UTC)

Reverted edits by 69.204.111.141
I've just reverted four edits by, who obviously means well but does not yet understand all of Wikipedia's rules. Here are the details:
 * APNG "should not be used for any production purposes whatsoever" I disagree. While APNG is not a good format for websites to serve, it is fine in more restricted environments -- for example, Firefox and its add-ons.
 * Less browser support than MNG but "difference has become negligible as of 2008" Such claims need sources, especially ones as surprising as this.
 * Changed heading of second column of multicolored table to "ASCII" Actually, some of that text is non-ASCII, so I've changed it to "As characters".
 * Refer to GIF as the "Compuserve file format" This would be good writing style in an essay but not in an encyclopedia.

I've also mostly reverted a corresponding edit to Multiple-image_Network_Graphics.

Let me explain how I see things. APNG is a hack to solve a problem in Gecko (layout engine), and is fine inside particular applications, but is not a good format for animations in general. It is not supported widely enough for general use on the web. So this article, though high in quality, is not particularly important. MNG is a great format when used with appropriate tools, but too poorly supported for web use. Animated/scripted SVG provides a way to display a sequence of raster images which will work in (almost?) every modern web browser, but the browser has to download each image separately instead of just downloaded one resource. None of these three alternatives is a clear winner; each is best suited to certain situations.) Cheers, CWC 13:48, 21 April 2012 (UTC) (Edited for clarity by CWC 01:28, 26 February 2013 (UTC))

mistakes?
"In effect this was a repeat of some of the same mistakes made in the GIF format 10 years earlier."

Maybe we should remove that phrase, as it's biased, not neutral. Why adding new features to an old format is automatically a mistake? Both GIF and PNG formats provide mechanisms for forward compatibility, GIF via extension blocks and PNG via third-party chunks. So why it's a mistake to utilize those mechanisms?

Forward compatibility is a feature, not a mistake. See: http://en.wikipedia.org/wiki/Forward_compatibility#PNG — Preceding unsigned comment added by Laststop (talk • contribs) 07:52, 6 November 2012 (UTC)

supported by chrome natively
can someone support this hypothesis 66.116.62.178 (talk) 13:53, 25 February 2013 (UTC)
 * No, Chrome does not support APNGs without a third-party addon, and there is no sign it ever will. (Tested in Chromium version 23.0.1271.97; see also the Chrome project's issue page for APNG.)
 * BTW, APNG now has an unexpected competitor for web animations: CSS3, specifically CSS Sprites in conjunction with either CSS Animations or a few lines of Javascript. Website developers are likely to find it far easier to use CSS3 than APNG, MNG or SVG.
 * Hope this helps — CWC 01:28, 26 February 2013 (UTC)
 * I disagree that CSS Sprites are supposedly easier to use, especially now there are programs that can create an APNG from a PNG sequence for you, which you then only need to insert into the page the same way you would with any other image. Browser support is an issue of course. --Benimation (talk) 22:53, 24 January 2015 (UTC)

Size comparison to MNG?
Considering the relationship, I would have liked a section mentioning something (roughly) about file sizes for same animations APNG vs. MNG. I appreciate the APNG library (code) is smaller than MNG, but by how much, and what's the impact on content size vs. code size? 85.229.218.51 (talk) 12:55, 26 September 2013 (UTC)

Confusing "Application support" table
It's unclear to me if the last section of the table (Mobile: iOS/Android/Internet Explorer/Opera Mobile) wants to compare browsers or operating systems. Also "partial" support in iOS is a strange notion, because it gives the impression that you can install a plugin/library that will add apng support to iOS, when it's really a library that developers must include in each application (by that measure every application whatsover has "partial" apng support; it's not worth mentioning imho). Generally i feel this should be a list of things that DO support apng, not of things that don't. In that spirit I'd like to remove the entire "mobile" section. Anyone against it? Kritzikratzi (talk) 14:49, 18 February 2014 (UTC)


 * Sounds fine to me. I think the main problem with the "mobile" section is that it lists operating systems (e.g. iOS, Android). Each OS has thousands of apps, and each of those apps may or may not support APNG. That's probably why PC OSs like Windows and Mac OS don't have entries in the table. It would make more sense to list the apps that support APNG, and not try to generalize based on OS. For example, a listing showing that Firefox for Android supports APNG. But the section as it is now is uselessly vague. I agree the article would be better with it gone. Foobaz·o&lt; 06:36, 21 February 2014 (UTC)

FFmpeg can create APNGs
It should be mentioned that FFmpeg can create APNGs. SoniEx2 (talk) 19:40, 15 November 2015 (UTC)

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