The MPEG-1 Codec - A Practical Guide to Video and Audio Compression - page 208

Luma Y' (16 x 16) B-Y' (8 x 8) R-Y' (8 x 8)

Figure 10-15 A picture of a macroblock.

level, the macroblock simply reduces to an average color across the entire block. This is the
DC coefficient for that block.
To see why that is, you need to understand what data is actually in the DCT-coded
version.

10.8.1 DCT—The Numbers Game

In Figure 10-15, a macroblock is shown as a series of pixels. Note that the chroma infor-
mation is half the resolution of the luma. The pixel values (shown as hexadecimal values)
are given in Figure 10-16.

B2 B7 C1 CB CE B0 7E 6E 75 7B 79 78 7D 7A 73 7B
AD AE B7 C5 D0 CE A8 79 64 69 74 75 76 76 72 76
9F A2 AE B7 BE C3 C6 A4 72 56 5C 63 6B 72 75 7D
89 8B 9C A5 AE B8 C2 CB A6 6D 55 5A 5B 5F 66 74
84 79 80 85 89 9D B0 C5 CF AD 7D 68 65 67 69 6E
7E 78 7B 74 71 7E 8F A4 C0 CA B1 81 6F 78 79 7A
7B 77 77 78 75 72 73 77 8C A9 C2 AA 7E 72 75 7E
7B 79 79 77 77 78 74 6B 66 79 98 A3 84 70 74 7C
7E 7A 79 77 78 7B 7D 7B 6F 6B 72 77 74 78 79 7E
80 7D 7D 77 77 77 7C 7E 7D 77 75 73 76 79 77 79
7D 7B 7D 7B 7E 7E 7D 80 81 7E 79 77 74 73 6D 6D
80 7B 7B 79 7F 80 7C 7A 73 6F 6C 70 71 78 7B 80
80 7D 7F 7B 7B 78 74 6D 6B 73 81 90 98 A3 A9 AB
81 7D 7B 74 6C 6B 76 7D 90 A1 B0 B8 B5 B7 B4 B4
82 75 6F 6C 6E 88 A3 B0 BC BC BA B8 B4 B3 B1 B4
7B 6A 80 94 A6 BE C2 C7 C5 BF BB B8 BC BF C4 CB

Luma Y' (16 x 16)

68 55 5E 59 56 60 67 77
57 49 4B 49 40 44 61 74
71 58 49 49 59 56 53 61
95 7A 7D 6D 58 4A 41 52
9F 98 B3 B3 9C 71 66 75
BD BE D8 D8 B9 89 69 6D
E8 D2 B0 90 6A 67 56 52
DD AA 80 6B 54 5C 5C 67

A3 A3 A4 77 4D 4E 67 99
54 6C 7A 4C 3F 3F 41 54
4C 40 40 3E 3E 3E 3E 4D
4E 3E 3C 3D 3E 3E 3F 4E
4E 3E 3D 3D 3E 3D 3F 4D
4D 3E 3D 3E 3C 3C 3E 4F
4B 3F 3F 40 40 48 51 76
5B 4E 4D 59 76 95 A8 B9

R-Y' (8 x 8)

B-Y' (8 x 8)

Figure 10-16 Pixel values of a macroblock.