05-31-2004, 12:48 AM
all digital video compression nowadays is typically made up of macroblocks, which are usually squares of pixels with widths and heights of a number divisible by 2 (unless the bitrate is high enough to allow for single pixles). When the bitrate gets too low, the codec will usually resort to making these blocks rather large, causing the image to turn into a mess of large blocks, instead of well-defined tiny blocks, or single pixles. This is a rather simplistic explanation as I'm no video codec designer. But to put it bluntly, macroblocking means the image looses resolution because of large blocks that appear in fast motion scenes.