A block is an 8 x 8 array of pixels. Four luma blocks plus a number of chroma blocks that depends on the chroma pixel structure (see Pixel Positioning ) indicated in the sequence header comprise a macroblock.

A block is the fundamental unit for the DCT (discrete cosine transform).

MPEG 2 Video Data Structures Topics:

- PIXEL

- BLOCK

- MACROBLOCK

- Field DCT Coding and Frame DCT Coding

- SLICE

- PICTURE

- GROUP of PICTURES (GOP)

- SEQUENCE

- PACKETIZED ELEMENTARY STREAM

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