User's Manual

Intel® 815 Chipset: Graphics Controller PRM, Rev 1.0
R
211
DWord Bits Description
1 22 Cb Block Pattern: Enable/disable intra-coded/correction data for the Cb block
21:18 Reserved: 00h
17:16 Horizontal Motion Vector Precision:
00 = 1/2 pixel
01 = 1/4 pixel (used for 2:1 down sampling)
10 = 1/8 pixel (used for 4:1 down sampling)
11 = Reserved
15:14 Vertical Motion Vector Precision:
00 = 1/2 pixel
01 = 1/4 pixel (used for 2:1 down sampling)
10 = 1/8 pixel (used for 4:1 down sampling)
11 = Reserved
13:12 Prediction Type:
00 = Intra-coded. (The motion vector fields are ignored. The Intra-coded values are
each 8 bits wide with no padding.)
01 = Forward prediction (Only the forward motion vector is used. The correction
data are signed 16 bit values)
10 = Backward prediction (Only the backward motion vector is used. The correction
data are signed 16 bit values)
11 = Bi-directional Prediction (Both the forward and backward motion vectors are
used. The correction data are signed 16 bit values)
11:8 Reserved: 00h
7:6 Destination Picture Structure: Specifies the structure of the destination surface
for predicting this block. The overall structure of the picture may be different, as in
field/frame prediction. This field overrides the vertical line stride and offset specified
in the DEST_BUFFER_VARIABLES instruction.
00 = Frame (Vertical stride = 1 line)
01 = Reserved
10 = Top Field (Vertical stride = 2 lines)
11 = Bottom Field (Vertical stride = 2 lines)
5 Reserved: 00h
4:3 Forward Reference Picture Structure: This field overrides the vertical line stride
and offset specified in the MAP_INFO instruction.
00 = Frame (Vertical stride = 1 line)
01 = Reserved
10 = Top Field (Vertical stride = 2 lines, offset = 0 lines)
11 = Bottom Field (Vertical stride = 2 lines, offset = 1 line)
2 Reserved: 00h
1 1:0 Backward Reference Picture Structure: This field overrides the vertical line stride
and offset specified in the MAP_INFO instruction.
00 = Frame (Vertical stride = 1 line)
01 = Reserved
10 = Top Field (Vertical stride = 2 lines, offset = 0 lines)
11 = Bottom Field (Vertical stride = 2 lines, offset = 1 line)