Utah RLE

Utah RLE (or URT RLE, or sometimes just RLE) is a raster image file format associated with the Utah Raster Toolkit software.

Format
A Utah RLE file contains the following entities, in this order. (Not all of them are present in every file.)
 * Fixed 15-byte header
 * Background color
 * Color map
 * Comments
 * Pixel data

Identification
Files begin with signature bytes.

Specifications

 * Design of the Utah RLE format (figure 2-1 and 2-2 are not included)

Software

 * Netpbm: rletopnm, pnmtorle (uses a fork of the Utah Raster Toolkit)
 * ImageMagick (format named "RLE"; read-only)
 * Utah Raster Toolkit source code: GraphicsMagick delegates → urt-*
 * Utah Raster Toolkit source code

Sample files

 * urt-img.tar
 * https://telparia.com/fileFormatSamples/image/utahRLE/