EXR to HEIC Converter

Encoding: the EXR uses none, RLE, ZIP, PIZ, PXR24, B44 or DWA, chosen per file; HEIC uses lossy HEVC (H.265) intra coding, on iPhones as a grid of 512×512 tiles, and the download is a HEIF file whose picture is JPEG-compressed rather than HEVC, because no HEVC encoder runs in a browser.

Bit depth: 16-bit half or 32-bit floating point per channel in the EXR; HEIC allows 8 or 10 bits per channel, and the HEIC 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; HEIC supports YCbCr, usually tagged Display P3 on iPhones, written here as 8-bit sRGB.

Transparency: the EXR stores it as an A channel stored like any other channel; HEIC could hold it as an auxiliary image item, rarely used by cameras, but this writer flattens it, so transparent areas are filled with the colour you choose.

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; HEIC can carry EXIF, XMP and an ICC profile, stored as items, 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.

HEIC is the default photo format on iPhones and many Android phones. It is about half the size of JPEG, but Windows, many websites and older software cannot open it without converting.

A HEIC is a HEIF file (ISO base media boxes with the brand 'heic'). iPhone photos store the picture as a grid of 512×512 HEVC tiles that the decoder stitches together, with the thumbnail, depth map and HDR gain map as further items.

HEIC is the better choice for storing photos on Apple devices, while EXR suits visual effects, compositing and 3D render output.

HEIC strengths: About half the size of JPEG; Stores depth maps, Live Photos and HDR. Drawbacks to weigh: Not supported by most websites and Windows apps; Patent-encumbered codec.