Imagination Pilots Matte Animation
- Company: Imagination Pilots
- FOURCCs: Ipma, Ip20
This is a simple LZW-based video codec with transparency pixels and delta frames. The LZW format according to Blown Away game technical analysis is the same as in GIF but without any additional data being present in the stream (it uses dynamic index size from 9 to 12 bits, code 256 means decoder reset and code 257 means end of stream).
Each frame consists of raw frame data compressed with LZW and with pixel value 0 used for transparent pixels (or unchanged pixels in delta frames) and pixel value 1 is used for pixels that should reuse the original background. In version 1 of the codec the first frame serves as the original background for the rest of the video, in version 2 there is no background stored in the video, those files are supposed to be partially transparent animations rendered over game scene.