An artifact of composite video sources in which dots seem to crawl between contrasting colors. Dot crawl is the result of an inexpensive comb filter that does not entirely separate the black and white from the color (the luma from the chroma). Also called "cross-luma." See
composite video and
comb filter.
Dots Crawling
Dot crawl (cross-luma) is noticeable at the boundary of contrasting colors such as blue and yellow. (Image courtesy of Home Theater and High Fidelity.)