iPhone 16 Adds JPEG XL
Jeremy Gray (Hacker News, Reddit):
Apple and its various software iterations have supported JPEG XL for at least a year, including in Finder, Preview, Final Cut Pro, Pages, Photos, Mail, Safari, and more. Adobe has also supported the format for a while, including in Adobe Camera Raw and Lightroom Classic.
Despite JPEG XL supporting reversible JPEG transcoding and being superior to JPEG in terms of quality and efficiency, the format has yet to be widely adopted. Neither Chrome nor Firefox, two very popular web browsers, support the format natively, for example. Extensions are available to support JPEG XL files, but they’re not installed by default.
The JPEG XL community website cites the format’s ability to reduce file size while delivering “unmatched quality-per-byte.” Compared to a standard JPEG, a JPEG XL file is up to 55% smaller while providing a cleaner image that is visually lossless. Gone are typical JPEG artifacts.
[…]
As Apple explains on the new iPhone models, JPEG XL files are supported on iOS 17 and later and macOS 14 and later. However, as mentioned, these .jxl files are wrapped in a DNG container, so you can’t just fire off .jxl files from the iPhone 16 Pro.
Compared to the HEIC format that Apple introduced several years ago, JPEG-XL supports both lossy and lossless compression. HEIC is a lossy format, and while it retains better quality than JPG images, pros will likely prefer JPEG-XL for zero image degradation. HEIC has never gained wide support, which has hindered its usefulness.
It sounds like Apple has only enabled Camera support for JPEG XL with the iPhone 16 family, not with iOS 18 generally. Is this because it depends on hardware acceleration that’s only available with the A18? However, iOS 17 and macOS 14 can read the files.
Also, although JPEG XL seems to be superior to HEIC, Apple is not offering it as a general choice alongside JPEG and HEIC. It’s only available when using ProRAW. This is all rather confusing.
Photo settings have gone too far. WTF is happening.
So JPEG XL seems flat out better than HEIC for images? I’m going to start saving all my film scans as 16 bit JPEG XL.
JPEG XL also supports re-encoding existing JPEG files to decrease file size while keeping the original file quality. That really seems like useful feature but so far I haven’t seen any tooling (in macOS) to re-encode my existing photo library.
Previously:
- iPhone 16 Pro Camera
- iPhone 16 and iPhone 16 Plus
- iPhone 16 Pro and iPhone 16 Pro Max
- ProRAW
- Goodbye, QuickTime 7 and JPEG 2000
- H.265/HEVC and HEIF
- JPEG 2000
Update (2024-10-23): Florian Pircher:
A lot of confusion, as you mentioned, since the new iPhones don’t use JXL for storing regular images, just for raw images. It used to be that regular images are either JPEG or HEIF and raw images are DNG with the pixel data stored as lossless JPEG. Now, regular images are the same as before, but for raw images you can choose how the pixel data inside the DNG should be stored: lossless JPEG (as before), lossless JXL, or lossy JXL.
Most people who have heard of JPEG XL have only seen it used for regular (non-raw) images. And few people know about the lossless JPEG format that was used before for DNG pixel data.
Update (2024-10-28): Jon Sneyers (2020, via Hacker News):
This section highlights the important features that distinguish JPEG XL from other state-of-the-art image codecs like HEIC and AVIF.
I found this interesting note in the article:
HEIC and AVIF can handle larger [than 35MP, 8MP respectively] images but not directly in a single code stream. You must decompose the image into a grid of independently encoded tiles, which could cause discontinuities at the grid boundaries. [demo image follows].
[…]
The newest Fujifilm X cameras have HEIC support but also added 40MP sensors--does this mean they are having to split their HEIC outputs into two encoding grids?It seems like the iPhone avoided this, as 48MP output is only available as a “ProRAW” i.e. RAW+JPEG, which previously used regular JPEG and now JPEG-XL, but never HEIC.
