AMD Geode™ LX Processors Data Book
401
Video Processor
33234H
6.7.6.4
Interface to Video Processor
The output from the Video Processor is connected via a
24-bit bus. Bytes on this bus are aligned as shown below:
[23:16]
Y
[15:8]
Cr (V)
[7:0]
Cb (U)
The VOP takes this 24-bit 4:4:4 data bus and converts it to
a 16-bit 4:2:2 data bus (the Y component on the high byte,
the U/V components alternating on the low byte).
The VOP provides three different methods for translating
from 4:4:4 to 4:2:2 data depending on the value of the
mode select bits from the VOP Configuration register (VP
Memory Offset 800h[5:4]) as shown in Table 6-61.
Mode 0: 4:2:2 Co-sited
In this mode, the U/V samples are dropped on alternating
sample sets, resulting in the below representation.
Sampling algorithm:
Y, U, V : 4:4:4 Input data
Y’, U’, V’ : 4:2:2 Sampled data
Y1’ = Y1, U1’ = U1, V1’ = V1
Y2’ = Y2
Y3’ = Y3, U3’ = U3, V3’ = V3
etc.
Mode 1: 4:2:2 Interspersed
In this mode, adjacent pairs of U/V sample data are aver-
aged, with the U/V samples coming from the same adja-
cent sample sets.
Sampling algorithm:
Y, U, V : 4:4:4 Input data
Y’, U’, V’ : 4:2:2 Sampled data
Y1’ = Y1, U1’ = (U1+U2)/2, V1’ = (V1+V2)/2
Y2’ = Y2
Y3’ = Y3, U3’ = (U3+U4)/2, V3’ = (V3+V4)/2
etc.
Mode 2: 4:2:2 Interspersed (free-running)
This mode is the same as Mode 1 with the exception that
the U sample is averaged between the first two samples,
and the V sample is averaged between the second and
third samples.
Sampling algorithm:
Y, U, V : 4:4:4 Input data
Y’, U’, V’ : 4:2:2 Sampled data
Y1’ = Y1, U1’ = (U1+U2)/2
Y2’ = Y2, V2’ = (V2+V3)/2
Y3’ = Y3, U3’ = (U3+U4)/2
Y4’ = Y4, V3’ = (V4+V5)/2
etc.
Table 6-61. VOP Mode
Mode
Bits
Description
0
00
4:2:2 Co-sited (Recommended)
1
01
4:2:2 Interspersed
2
10
4:2:2 Interspersed, free-running
Luminance (Y) Samples
Chromance (U,V) Samples
Luminance (Y) Samples
Chromance (U,V) Samples
Luminance (Y) Samples
Chromance (U) Samples
Chromance (V) Samples
Summary of Contents for Geode LX 600
Page 14: ...14 AMD Geode LX Processors Data Book Overview 33234H...
Page 20: ...20 AMD Geode LX Processors Data Book Architecture Overview 33234H...
Page 44: ...44 AMD Geode LX Processors Data Book Signal Definitions 33234H...
Page 88: ...88 AMD Geode LX Processors Data Book GLIU Register Descriptions 33234H...
Page 618: ...618 AMD Geode LX Processors Data Book Electrical Specifications 33234H...