Phodos JXL

If you’ve kept a photo collection for years, you’ve probably moved it between apps, computers, and drives. I’m building Phodos as a photo library that keeps your originals intact while making copies you can view or share. Phodos JXL handles JPEG XL image files for that library, and other apps will be able to use the same engine.

Why JPEG XL?

JPEG XL is an image format that can compress a photo without changing its pixels. It also has a way to pack an existing JPEG into a smaller file and later get back the exact original JPEG. Restoring the original file also preserves details like its metadata and the way it was encoded.

What I’m building

The foundation is a decoder, the software that turns a compressed image file into pixels an app can display. For Phodos, the next goal is to use that decoder to make viewing copies while keeping track of how the file describes the photo’s colors. Writing JPEG XL files and restoring original JPEGs are also part of the engine’s development.

When a file is cut short

If a file copy is interrupted, an app might still be able to show part of the picture. A photo library checking a copy needs the decoder to report that data is missing. A recovery tool might want whatever the decoder can still read. Phodos JXL calls these two ways of reading a file strict mode and salvage mode.