RGBE
RGBE is a pixel encoding used for high-dynamic-range (HDR) imaging, short for Red, Green, Blue, Exponent. In this scheme, each pixel is stored as four bytes: one byte for each color channel (R, G, B) and one byte for a shared exponent (E). The four-byte value represents a color in the form (R/255, G/255, B/255) × 2^(E−128). If the pixel is black, all four bytes are zero. The exponent provides a common scale for the three color channels, allowing a wide dynamic range to be represented with only 8 bits per channel.
To decode, read the four bytes. If E is zero, the color is (0, 0, 0). Otherwise,
RGBE was popularized by the Radiance HDR format, developed for lighting and rendering workflows. It enables
RGBE provides a compact four-byte-per-pixel representation with a broad dynamic range. However, the 8-bit mantissas introduce