Line of slightly but continuously moving dots found where there is a sharp color separation in a vertical line (for instance, where a bright blue rectangle meets a bright red rectangle in an image) resulting from poor chrominance/luminance filtering. Dot crawl is an annoying picture distortion. If the video display does not properly separate a composite video signal (video signal with the brightness – luminance – and color – chrominance – portions of the video signal combined), dot crawl may occur.