experimenting with jpegli

johnrmoyer — Fri, 01 May 2026 15:31:44 GMT

I have been experimenting with jpegli. I hope that some of this might be helpful to others.

I have already requested on CPS an enhancement to DPP to use jpegli to encode JPG files. HIF files are superior to JPG, but not all web browsers will display the HIF files. When using jpegli, one gets a much smaller file at the same quality level and much better quality at the same file size. In areas of an image that have gradual changes in color or brightness is where jpegli makes the biggest difference.

The libjxl source code includes jpegli. JPEGXL is also superior to JPEG, but is even less widely supported by web browsers than HIF.

I save a 16 bit TIF from DPP along with a JPG at what DPP calls quality 10 at the same time. I also save a dr4 recipe file as a record of my edits. I use exiftool to display the contents of the dr4 file and to add standard IPTC, MWG and XMP metadata.

I built jpegli from the libjxl source code on my Debian Linux machine and installed it to /usr/local/bin.

I wrote a web page that has one of my photos, some of the camera settings, all of the edits in DPP, the command lines I used, and links to versions of the image.

The versions include straight out of camera JPG, JPG saved by DPP, JPG created using jpegli, and the difference between JPG saved from DPP and JPG created by jpegli.

I was influenced by https://www.nature.com/articles/s41467-025-64679-2 to use 4:4:4 quantization instead of the 4:2:2 quantization done by DPP. "Ashraf, M., Chapiro, A. & Mantiuk, R.K. Resolution limit of the eye — how many pixels can we see?. Nat Commun 16, 9086 (2025). https://doi.org/10.1038/s41467-025-64679-2"

The webpage that I made is at: https://www.rsok.com/~jrm/2026Apr30_birds_and_cats/IMG_5771c_2026apr03_titmouse.html

Tufted Titmouse (Baeolophus bicolor) in Norman, Oklahoma, United States on April 3, 2026

difference between image save by DPP and image created by jpegli from 16 bit TIF that had been saved from DPP:

IMG_5771_diff.jpeg is the difference between IMG_5771c.JPG and IMG_5771c2.JPG

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experimenting with jpegli