GRFX

GRFX is a raster graphics file format used for storing logos and splash screens in some AMI BIOSes.

Structure
All number values are little-endian.

The file begins with this structure:

After this header, another structure follows.

After this structure, the bitmap data follows. Pixels are stored row by row, each row stores pixels left to right. Each byte contains data for two pixels; the more significant 4 bits store the left pixel of the pair.

It is not known to this author how the file format is supposed to behave for bitmap widths not divisible by two, or for palette sizes other than 16.

Links

 * GRFX to PPM converter (with source code)