What is a macroblock?

What is a macroblock?

Jump to navigation Jump to search. Macroblock is a processing unit in image and video compression formats based on linear block transforms, such as the discrete cosine transform (DCT). A macroblock typically consists of 16×16 samples, and is further subdivided into transform blocks, and may be further subdivided into prediction blocks.

How many samples are in a macroblock?

A macroblock typically consists of 16×16 samples, and is further subdivided into transform blocks, and may be further subdivided into prediction blocks. Formats which are based on macroblocks include JPEG, where they are called MCU blocks, H.261, MPEG-1 Part 2, H.262/MPEG-2 Part 2, H.263, MPEG-4 Part 2, and H.264/MPEG-4 AVC.

What is the size of a 16×16 macroblock?

In H.261, the first video codec to use macroblocks, transform blocks have a fixed size of 8×8 samples. In the YCbCr color space with 4:2:0 chroma subsampling, a 16×16 macroblock consists of 16×16 luma (Y) samples and 8×8 chroma (Cb and Cr) samples. These samples are split into four Y blocks, one Cb block and one Cr block.

How many luminance blocks are in a macroblock?

A macroblock contains a 16 × 16-luminance area and the corresponding chrominance areas of two chrominance components (for 4:2:0 chroma-format, a macro-block contains a 16 × 16 luminance block and an 8 × 8 chrominance block from each of the chrominance components).