CorePNG codec

See http://corepng.corecodec.org/ for details

Source available (c++ vfw and dshow codecs).

Description from website:
CorePNG is a lossless codec based on PNG. Essentially, each frame is 
compressed as a PNG, so if PNG does it, this codec does too. (RGBA) This 
codec also has the ability to write P frames and to autodetect when it should. 
The P frame takes the difference of the previous frame and the current frame 
and encodes that as a PNG.