NEW272350
JPEG XL: Progressive decoding 
https://bugs.webkit.org/show_bug.cgi?id=272350
Summary JPEG XL: Progressive decoding
Rogier de Ruijter
Reported 2024-04-08 13:44:24 PDT
When loading a JPEG XL Image the image does not progressive decode. This is also not the case in Firefox nightly. So I am not sure if the Safari is the actual problem, but it feels like it. Here is a reproduction. This is the HTML: ``` <!doctype html> <html lang="en"> <head> <meta charset="UTF-8" /> <title>Test progressive decoding JPEG XL</title> </head> <body> <img src="output.jxl" /> </body> </html> ``` This is how the JPEG XL is created: `cjxl input.jpeg output.jxl --progressive_dc=1` `cjxl` referece to this library https://github.com/libjxl/libjxl?tab=readme-ov-file. `--progressive_dc=1` should be the flag that enables progressive decoding on the JPEG XL.
Attachments
An JPEG XL image that can be progressively decoded (2.39 MB, image/jxl)
2024-04-09 01:02 PDT, Rogier de Ruijter 		no flags
Details
A JPEG image that can be used to transform (2.89 MB, image/jpeg)
2024-04-09 01:04 PDT, Rogier de Ruijter 		no flags
Details
View All Add attachment proposed patch, testcase, etc.
Said Abou-Hallawa
Comment 1 2024-04-08 17:14:05 PDT
Can you please attach a sample JPEGXL image which can be decoded progressively? My understanding is not all images can be decoded progressively.
Rogier de Ruijter
Comment 2 2024-04-09 01:02:33 PDT
Created attachment 470833 [details] An JPEG XL image that can be progressively decoded Hi Said, Of course I can! Here is an image that can be progressively decoded. The command used to create this is in the comment above.
Rogier de Ruijter
Comment 3 2024-04-09 01:04:04 PDT
Created attachment 470834 [details] A JPEG image that can be used to transform For reference here is also the original image used.
Rogier de Ruijter
Comment 4 2024-04-09 03:19:18 PDT
I tested the progressive loading in the Thorium browser and I can confirm that the JPEG XL image attached here can be progressively loaded.
Radar WebKit Bug Importer
Comment 5 2024-04-15 13:56:06 PDT
<rdar://problem/126505280>
Jake Archibald
Comment 6 2025-10-06 02:29:09 PDT
https://random-stuff.jakearchibald.com/apps/partial-img-decode/?demo=fox-progressive.jxl - another test case. Drag the slider. JPEG-XL can in theory produce a fairly representative render after around 6kb, and something representative of colour even sooner than that (testing via https://jxl-oxide.tirr.dev/demo/index.html).
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