EXR to BMP Converter

Encoding: the EXR uses none, RLE, ZIP, PIZ, PXR24, B44 or DWA, chosen per file; BMP uses usually none; RLE for some 4 and 8-bit files, and the download is an uncompressed 24-bit BMP, or 32-bit with alpha when the image has transparency.

Bit depth: 16-bit half or 32-bit floating point per channel in the EXR; BMP allows 1, 4, 8, 16, 24 or 32 bits per pixel, and the BMP written here has 24 or 32 bits per pixel. 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; BMP supports RGB or an indexed palette, written here as 8-bit sRGB.

Transparency: the EXR stores it as an A channel stored like any other channel; the BMP keeps it as an optional fourth byte in 32-bit files, which many programs ignore.

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; BMP can carry nothing beyond the header's resolution fields (and a colour profile in rare V5 headers), 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.

BMP stores raw, uncompressed pixels. Files are huge but trivially simple, which is why some legacy Windows software, embedded displays and printers still ask for it.

A BMP is a 14-byte file header ('BM' and the offset to the pixels), a DIB header (40 bytes, or 108 and 124 bytes in the V4 and V5 versions that add colour masks and alpha), an optional palette, then pixel rows padded to 4 bytes and normally stored bottom-up.

BMP is the better choice for legacy software and embedded systems that require it, while EXR suits visual effects, compositing and 3D render output.

BMP strengths: No compression artifacts; Read by very old and very simple software. Drawbacks to weigh: Enormous files; Poor support for transparency; No metadata.