Wikipedia
Huffyuv
Huffyuv (or HuffYUV) is a lossless video codec created by Ben Rudiak-Gould which is meant to replace uncompressed YCbCr as a video capture format. The codec can also compress in the RGB color space.
"Lossless" means that the output from the decompressor is bit-for-bit identical with the original input to the compressor. Lossless only occurs when the compression color space matches the input and output color space. When the color spaces do not match, a low loss compression is performed.
Huffyuv's algorithm is similar to that of lossless JPEG, in that it predicts each sample and then Huffman-encodes the error.