Alaris VideoGramPiX

• FourCCs: VGPX
• Company: Alaris

Sample Java player available here: http://www.ila-ila.com/xvd-hist/sites/vgram/index.htm

The codec works by reading a code for an operation using a codebook and performs some action on pixels (RGB triplets in this case) depending on it (usually copy, skip or average):

• 0 - skip current pixel
• 1 - copy left pixel value
• 2 - copy top pixel value
• 3 - copy right pixel value
• 4 - copy bottom pixel value
• 5 - set pixel to an average of top and left pixels
• 6 - set pixel to an average of top and right pixels
• 7 - set pixel to an average of bottom and right pixels
• 8 - set pixel to an average of bottom and left pixels
• 9 - read a code for pixel difference (each codebook entry has differences for every component)
• 10 - skip a number of pixels the number of times defined in frame header
• 11 - repeat left pixel value the number of times defined in frame header

Something similar can be found in an alternative frame coding method for VT codec of VGM Video family.