WebP to ORF Converter

Encoding: the WebP uses lossy VP8 coding or lossless VP8L; 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 bits per channel in the WebP; ORF allows 12 bits per channel, and the DNG written here has 8 bits per channel, linearised.

Colour: RGB; lossy WebP stores colour at half resolution (4:2:0) in the WebP; ORF supports camera RGB from a Bayer mosaic, written here as 8-bit sRGB.

Transparency: the WebP stores it as a separate alpha plane, available in lossy as well as lossless files; the DNG has none, so transparent areas are filled with the colour you choose.

Animation: ANMF frame chunks, each with its own delay and blending; the DNG holds one image, so only the first frame is converted.

Metadata: the WebP can carry EXIF, XMP and ICC chunks; ORF can carry EXIF and Olympus maker notes, which also contain the preview, but nothing is copied across.

WebP is Google's web image format. It supports lossy and lossless compression, transparency and animation, and is typically 25 to 35 percent smaller than JPEG at the same visual quality.

A WebP is a RIFF file: 'RIFF', a length, 'WEBP', then chunks. A simple lossy file is one VP8 chunk and a lossless one is VP8L; the extended VP8X header announces alpha, animation, ICC, EXIF or XMP chunks.

WebP files usually come from websites, Chrome's Save image as, CDNs and Android apps.

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 WebP 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.