Artifact in the luminance channel due to deficiency of Y/C separation in the decoder. It looks like parasitic dots at the sharp or moving edges of saturated colored objects.
Dot crawl affects the edges of colour and manifests itself as moving dots of colour along these edges. It is an inherent flaw in both the PAL and NTSC video systems and cannot be eliminated fully once it has been introduced into the video stream. It is mainly an artifact of composite video processing but is also present on some digital sources. Can be slightly overcome in anime by using warpsharp. (More)
An artifact of composite video signals that appears as a moving, zipper-like, vertical border between colors.