Intel® 815 Chipset: Graphics Controller PRM, Rev 1.0

R

DWord

1

1

Bits

Description

22Cb 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)

5Reserved: 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)

2Reserved: 00h

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)

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Image 211
Intel 815 manual DWord Bits, Vertical Motion Vector Precision 00 = 1/2 pixel, Prediction Type