These definitions are from Wikidpedia.
Macroblock
Macroblock is a term used in video compression, which represents a block of 16 by 16 pixels. Each macroblock contains 4 Y block, 1 Cb block, 1 Cr block (4:2:0). (It also could be represented by 4:2:2 or 4:4:4 YCbCr format). Macroblocks can...