AVIF to ORF Converter

Encoding: the AVIF uses lossy or lossless AV1 intra-frame coding; 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, 10 or 12 bits per channel in the AVIF; ORF allows 12 bits per channel, and the DNG written here has 8 bits per channel, linearised. 10 and 12-bit AVIFs, including HDR ones, are decoded to 8 bits per channel.

Colour: YUV 4:4:4 or 4:2:0 with BT.709, Display P3 or BT.2020 primaries, HDR curves possible in the AVIF; ORF supports camera RGB from a Bayer mosaic, written here as 8-bit sRGB.

Transparency: the AVIF stores it as an auxiliary AV1 image stored beside the colour image; the DNG has none, so transparent areas are filled with the colour you choose.

Animation: an AV1 image sequence under the 'avis' brand; the DNG holds one image, so only the first frame is converted.

Metadata: the AVIF can carry EXIF, XMP and ICC stored as HEIF items; ORF can carry EXIF and Olympus maker notes, which also contain the preview, but nothing is copied across.

AVIF uses the AV1 video codec for still images. It is the most efficient widely supported format, often half the size of JPEG, with HDR, wide colour and transparency, but encoding is slow.

An AVIF is a HEIF file, the same ISO base media boxes as MP4, with the brand 'avif'. The picture is an AV1 key frame stored as an image item, and its size, colour and pixel layout are item properties.

AVIF files usually come from image CDNs, modern web build pipelines and some recent phones.

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 AVIF 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.