396 AMD Geodeā„¢ LX Processors Data Book
Video Processor
33234H
Figure 6-28. Color Key and Alpha-Blending Logic
No
Yes
Yes
No
Yes
No
No
Yes
No
Yes

Notes:

1) VG_CK: Video/Graphics color key select (VP Memory

Offset 008h[20]). Selects whether graphic data is used

for color keying or video data is used for chroma keying.

2) GFX_INS_VIDEO: Graphics inside Video (VP Memory

Offset 098h[8]). Graphics inside video enable.

3) Graphics [31:24] = 00h: Graphics color key match

if VG_CK = 1, Graphics(31:24) is pixel alpha value.

No
Yes
Yes
No
No
No Yes
Yes
No
Start
Cursor color
key matches
graphics value?
Pixel inside
the video
window?
Use selected
cursor color
for pixel.
Use graphics
value for this
pixel.
Pixel inside
Alpha window?
Video pixel
Blend graphic
values and video
values using the
Alpha value for
this window
Replace the pixel
with the color
register value
value
for this pixel

Use video value

for this pixel

Color register
video pixel matches
VG_CK = 1? VG_CK = 1?
matches chroma
Color register
enabled for this
window?
Yes
Use video value
for this pixel
No
Yes
Yes
chroma key?
VG_CK = 1?
Yes
key?
Graphics [31:24] =
enabled for
this window?
Use graphics value
for this pixel
Use graphics
Per-pixe l
alpha blending
enabled?
No
No
Blend graphic
values and video
values using the
Alpha value for
this pixel
Yes
GFX_INX_VIDEO = 1?
00h?
No
graphics[31:24] =
00h?