JXL to ORF Converter

Encoding: the JXL uses lossy VarDCT or lossless modular coding; existing JPEGs can be repacked without loss; ORF uses losslessly compressed sensor data, with a preview and thumbnail, and the download is a Linear DNG: demosaiced 8-bit RGB with the colour matrices raw editors need.

Bit depth: 8 to 16 bits per channel, or floating point in the JXL; ORF allows 12 bits per channel, and the DNG written here has 8 bits per channel, linearised. High-bit-depth JPEG XL files are reduced to 8 bits per channel.

Colour: sRGB, Display P3, linear and other spaces described in the codestream in the JXL; ORF supports camera RGB from a Bayer mosaic, written here as 8-bit sRGB.

Transparency: the JXL stores it as an extra channel in the codestream; the DNG has none, so transparent areas are filled with the colour you choose.

Animation: frames inside a single codestream; the DNG holds one image, so only the first frame is converted.

Metadata: the JXL can carry EXIF and XMP boxes in the container form, often stripped by encoders; ORF can carry EXIF and Olympus maker notes, which also contain the preview, but nothing is copied across.

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 files usually come from image editors, archival pipelines and lossless JPEG recompression.

ORF is the raw format of Olympus and OM System cameras, built around Four Thirds and Micro Four Thirds sensors. It stores 12-bit sensor data with a JPEG preview kept inside Olympus's maker notes.

ORF looks like TIFF but replaces the version number 42 with the letters 'RO', so a little-endian file starts 'IIRO' and generic TIFF readers reject it. Its JPEG preview is not in the main image directory but inside the camera-settings block of Olympus's maker notes.

ORF files come from Olympus E-series DSLRs, OM-D and PEN mirrorless cameras and OM System bodies.

Forms and workflows that ask for ORF usually feed a raw editor, and each of those opens DNG as well, so the DNG can take the ORF's place. Keep the JXL if you only need to view or share the picture.

What ORF offers when it comes straight from the camera: Compact files from a smaller Four Thirds sensor; High Res Shot results stored as a single file; Supported across two decades of Olympus and OM System bodies. Its drawbacks: An 'IIRO' header that generic TIFF readers reject; 12-bit depth, less than most full-frame raw files; A preview hidden inside the maker notes.