Autodesk Animator Codec

Autodesk Animator Codec (AASC) is a 24-bit Run Length Encoding algorithm similar to Microsoft RLE.

Decoding Algorithm

A frame of AASC data is decoded bottom row first and the decode operation iterates to the top row.

foreach row from bottom to top
- read the next byte from the encoded stream as the RLE code
- if RLE code is 0
  - read the next byte from the encoded stream as the command code
  - else if the command code is 0
    - row decode finished; move to the next row
  - else if the command code is 1
    - frame decode is finished
  - else if the command code is 2
    - reposition the frame decode coordinates:
    - read the next byte as the number of pixels to move to the right
    - read the next byte as the number of rows to move up
  - else
    - copy the next (command code) pixesl from the encoded byte to the output image
    - if the command code is odd
      - skip the next byte in the encoded bytestream
else
- read the next byte as the pixel
- write the pixel into the output image (command code) times