[b15h0p]

To increase adoption they should not have limited this to the latest iPhone models. Why on earth can a one year old iPhone 15’s CPU not handle encoding JXL? It can encode 4K video in real time, so this should be no problem at all, right?

[WhyNotHugo]

This is how they sell new phones. The grand majority of new features don't require the latest hardware, but artificially restricting it increases sales of new phones. None technical people can't usually tell the difference between hardware and software clearly enough to understand this nasty trick.

[illiac786]

To be fair it’s less bad than what some other vendors are doing, which is stopping to provide updates. Not saying apple is an angel, they intentionally generate ewaste by withholding such features…

[marcellus23]

I don't think anyone is deciding to buy a new phone or not based on JPEG XL support.

[alwillis]

From the article:

    As Apple explains on the new iPhone models, JPEG XL files are supported
    on iOS 17 and later and macOS 14 and later.

JPEG XL isn't limited to the latest phones; just a phone that can run iOS 17 or later. I have used JPEG XL on my iPhone 13 mini with no issues. iOS 17 runs on the iPhone XS (2018) or newer.

The difference is JPEG XL is now part of the Apple's image pipeline for the camera in iPhone 16.

Any 3rd party photo app developer can support JPEG XL if they wish.

[jiggawatts]

One of the tricks for achieving the target battery life is that photo and video formats are offloaded to dedicated and very power-efficient hardware in all mobile devices. The iPhone 16 is the first to get hardware offload for AV1 and JXL, which is why it'll support these formats.

It's not just software, unlike in the PC world where going from 5W hardware decode to 50W software decode basically doesn't matter.

[illiac786]

Is that documented somewhere?

[account42]

The "CPU" (that is, the generic compute part) cannot encode 4K video in real time, that part is handle by codec-specific HW.

[lonjil]

They aren't doing JXL encoding in hardware though. Zero chance that the new iPhone chip has hardware acceleration for JXL. Definitely just plain old CPU encoding.

And we're not talking about video anyway, this is about ProRAW, a still image format.

[NinoScript]

I’d guess hardware acceleration could have something to do with it

[JyrkiAlakuijala]

I don't know, but my guesswork is that the DNG/ProRAW/JXL support comes with compatibility challenges. Limiting the size of the launch to well-informed photography prosumers and professionals will help to iron out the compatibility challenges — rather than make all confused consumers face these challenges at once.

I don't think that hardware support plays a role here. The fastest encoding modes of JPEG XL are ridiculously fast on software, and Apple's CPUs seem powerful enough.

[cchi_co]

It does seem odd to restrict new features to the latest models, especially when older ones still have powerful capabilities.

[alwillis]

Apple announced support for JPEG XL last year at WWDC; Apple's 1st party apps supported JPEG XL when iOS 17 shipped: https://developer.apple.com/wwdc23/10122

Regarding older hardware, I addressed that: https://news.ycombinator.com/item?id=41611709

[Asmod4n]

It’s good in a corporate setting, you don’t want to suddenly have to deal with a new file format for which you won’t have an app installed on your company PCs to view them.

[the4anoni]

This, I just don't understand why it seems only latest iPhones got this.

[rob74]

I also don't know, but I suspect the fact that Apple not only develops the OS, but also sells the devices, might have something to do with it...

[FollowingTheDao]

This makes me think: If JPEG-XL needs more computing power to decompress, does that out weigh the ecological benefit benefit of the smaller file size?

[pornel]

JPEG XL is pretty cheap to decompress.

Advancements in compression algorithms also came with advancements in decompression speed. New algorithms like tANS are both compressing well, and have very fast implementations.

And generally smaller files decompress faster, because there's just less data to process.

[brigade]

The CPU isn’t used for encoding video

[LtdJorge]

Encoding a single image with the CPU takes nothing compared to modern video codecs.

[lonjil]

There's literally no way Apple developed a hardware accelerator for JXL encoding. So they're definitely using some kind of a CPU or generic DSP.