SGI (image file format)

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File Format
Name SGI (image file format)
Ontology
Extension(s) .sgi, .bw, .rgb, .rgba
PRONOM x-fmt/140

SGI (also known as IRIS, and sometimes called RGB or Irix RGB) is a raster image file format. The image may be uncompressed, or use RLE compression.

SGI probably stands for Silicon Graphics Image.

Contents

Image types

SGI supports the following image types:

  • Grayscale, 8 or 16 bits/sample
  • RGB, 8 or 16 bits/sample
  • RGBA, 8 or 16 bits/sample
  • RGB 3-3-2, 8 bits/pixel (obsolete)
  • Colormapped (but no palette is stored in the file) (obsolete)
  • Colormap (file contains only a palette; no image) (obsolete)

Format

SGI files start with a 512-byte fixed header, most of which is unused. If the image is uncompressed, the pixel data follows. Compressed images have a scanline table, followed by the compressed pixel data.

The pixel data is stored from bottom-up, instead of top-down as in most image formats.

Identification

SGI files begin with bytes 01 DA.

Specifications

Software

Sample files

External links

Personal tools
Namespaces

Variants
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