EXR to JXL Converter

Encoding: the EXR uses none, RLE, ZIP, PIZ, PXR24, B44 or DWA, chosen per file; JXL uses lossy VarDCT or lossless modular coding; existing JPEGs can be repacked without loss, and the download is a JPEG XL encoded with libjxl compiled to WebAssembly, lossy at the quality you choose or lossless.

Bit depth: 16-bit half or 32-bit floating point per channel in the EXR; JXL allows 8 to 16 bits per channel, or floating point, and the JXL written here has 8 bits per channel. Floating-point values are mapped to 8 bits per channel, and anything brighter than white clips.

Colour: scene-linear RGB, often ACEScg or linear Rec.709 in the EXR; JXL supports sRGB, Display P3, linear and other spaces described in the codestream, written here as 8-bit sRGB.

Transparency: the EXR stores it as an A channel stored like any other channel; the JXL keeps it as an extra channel in the codestream.

Other images: the EXR can hold extra channels (depth, normals, render passes) and multiple parts; only the main image is converted.

Metadata: the EXR can carry named header attributes such as chromaticities, timecode and camera data; JXL can carry EXIF and XMP boxes in the container form, often stripped by encoders, but nothing is copied across.

OpenEXR is the high dynamic range format of film visual effects. It stores half or full floating-point channels in linear light, plus any extra render passes, and is the working format of compositing pipelines.

An EXR starts with the magic number 76 2F 31 01 and a version field, then a header of named, typed attributes (channels, compression, dataWindow, displayWindow) and a table of offsets to scanline or tile blocks.

EXR files usually come from 3D renderers and compositing in Nuke, Blender, Houdini, After Effects and DaVinci Resolve.

JPEG XL is a next-generation format designed to replace JPEG. It compresses better than JPEG and WebP, supports lossless, HDR and progressive decoding, and can losslessly repack existing JPEGs.

A JPEG XL file is either a bare codestream starting with FF 0A or an ISO base media container whose 'jxlc' box holds the codestream. A recompressed JPEG keeps a 'jbrd' box that lets the original JPEG bytes be rebuilt exactly.

JXL is the better choice for archiving and future-proof high quality storage, while EXR suits visual effects, compositing and 3D render output.

JXL strengths: Excellent lossy and lossless compression; Progressive decoding and HDR; Huge image sizes. Drawbacks to weigh: Browser support is limited (Safari only by default); Few apps can open it yet.