Comment on PNG has been updated for the first time in 22 years — new spec supports HDR and animation
db2@lemmy.world 4 days ago
But is it backwards compatible with an old version that can’t be updated?
Speaking for animation, your browser probably already supports APNG. APNG is 21 years old and has decent adoption. But it’s officially part of the club.
That said, APNGs are fat as fuck and they’re a pretty old solution to animated graphics with an alpha channel. Don’t expect to see everyone making APNGs all of the sudden. There is a reason why people have kept it at a distance.
Some of this is paving the cowpath - the animated PNG stuff is 20 years old and e.g. Firefox has had support since March 2007.
I’m probably gonna be massively downvoted for saying the forbidden word but I asked AI to do a summary with references of the forward and backward compatibility of PNG’s new version:
!
Based on recent search results, the new PNG specification (Third Edition) and its reference library (libpng) maintain strong backward compatibility while introducing modern features. Here’s a detailed compatibility analysis:
png_struct/png_info internals since 1.5.0) ensures older apps using png_get_*/png_set_* functions remain compatible. Direct struct access, deprecated since 1.4.x, may break in libpng 2.0.x (C99-only) .png_image_free()) were patched in libpng 1.6.37+, making the new lib safer for decoding old files .IHDR or IDAT remain unchanged .mDCv chunk. Older libs ignore HDR data, falling back to SDR, which may cause color inaccuracies .eXIf chunks are ignored by legacy decoders, losing metadata like GPS or copyright info .| Scenario | Compatibility | Key Considerations |
|---|---|---|
| Old PNG → New Lib | ✅ Excellent | Legacy files work flawlessly; security improved. |
| New PNG → Old Lib | ⚠️ Partial | Basic rendering works, but HDR/APNG/EXIF ignored. Security risks in unpatched versions. |
| New Features | 🔧 Conditional | Requires updated apps (e.g., Photoshop, browsers) and OS support . |
For developers: Use png_get_valid(png_ptr, info_ptr, PNG_INFO_mDCv) to check HDR support and provide fallbacks .
!<
downvoters: is it wrong?
I don’t know. If the poster couldn’t be bothered to fact-check, why would I? It is just safer to assume that it is misinformation.
If you prefer to know nothing about PNG compatibility rather than something that might be true about PNG. That’s fine but definitely not my approach.
Also, as I said to another commenter. Critical thinking is not some tool you decide to use on some comments and not others. An AI answer on some topics is actually more likely to be correct than an answer by a human being. And it’s not some stuff I was told by an AI guru it’s what researchers are evaluating in many universities. Ask an human to complete various tasks and then ask the AI model and compare scientifically the data. And it turns out there is task where the AI outperforms the human pretty much all the time.
YET on this particular task the assumption is that it’s bullshit and it’s just downvoted. Now I would have posted the same data myself and for some reason I would not see a single downvote. The same data represented differently completely change the likelihood of it being accurate. Even though at the end of the day you shouldn’t trust blindly neither a comment from an human or an AI output.
Honestly, I’m saddened to see people already rejecting completely the technology instead of trying to understand what it’s good at and what it’s bad at and most importantly experiencing it themselves.
I wanted to know what was generative AI worth so I read about it and tried it locally with open source software. Now I know how to spot images that are AI generated, I know what’s difficult for this tech and what is not. I think that’s a much healthier attitude than blindly rejecting any and all AI outputs.
Considering it named CVE-2019-7317, which was fixed in April 2019, it’s already hallucinating and not worth reading further into it.
As you can see it’s irrelevant apparently. If it’s AI generated it will be downvoted.
It’s not irrelevant, it’s that you don’t actually know.
If you started your comment by saying “This is something I completely made up and may or may not be correct” and then posted the same thing, you should expect the same result.
Yes that’s why its so great
The PNG format is made of chunks that have determined roles, and provides provisions for newer “standardized” chunks alongside the custom chunks it had supported until now. It is likely that PNG made with newer software that does not use new features, or uses only additional features, will remain readable by older software to some extent.
I’ll tell you if I can find some new files for testing.
Even JPEG isn’t always back compatible either. I loaded an image into my software which uses some ancient library internally, and it swapped the blue and red channels.
otacon239@lemmy.world 4 days ago
Yeah, this was my first thought. How many slightly older, no-longer-being-updated pieces of software will fail to open the new version? Hopefully it’s built in a way that it just falls back to legacy and ignores the extra information so you can at least load the file.
pennomi@lemmy.world 4 days ago
This is all the article mentions. I hope you’re right about the backwards compatibility.
ouRKaoS@lemmy.today 4 days ago
I remember the Wild West Web days when it was a toss up seeing if animated Gifs, transparencies in images, or the specific hexadecimal for your personal shade of purple you created would render properly between browsers.
Image
hakunawazo@lemmy.world 4 days ago
Image
dual_sport_dork@lemmy.world 4 days ago
I mean, that’s already how animated .gifs work. If somehow you manage to load one into a viewer that doesn’t support the animation functionality it will at least dutifully display the first frame.
How the hell you would manage to do that in this day and age escapes me, but there were a fair few years in the early '90s where you might run into that sort of thing.
awesomesauce309@midwest.social 4 days ago
Probably most notably the iOS photos app until like 2014
BurgerBaron@piefed.social 4 days ago
One example is piefed unfortunately. Animated gifs as avatar or banner don't animate currently as far as I can tell.
dual_sport_dork@lemmy.world 4 days ago
Those are displayed in browser, right? The only reason that would be happening is if Piefeed is recompressing images and their code is not smart enough to identify an animated .gif and act accordingly.