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.
CorePNG was originally developed for use with the subtitles, it compresses cartoons and CGI very well and in many cases better than Huffyuv and Loco at the expense of time.
Compression Tests Using a 31.44 second DivX 3 Simpsons clip. 01:47.265 - 02:18.472 S03E17 - 8F13 Homer at the Bat 512x384 pixels 31.44 seconds 752 frames No audio
|130,582KB||All I frames Fastest|
|113,192KB||All I frames Normal|
|109,812KB||All I frames Best|
|73,654KB||2 P frames Normal|
|61,868KB||100 P frames Fastest|
|50,369KB||100 P frames Normal|
|49,189KB||100 P frames Best|
|40,603KB||1000 P frames Best with Auto-Delta frames|