AMD Geode LX 800@0.9W - Manual (Page 396)

396 AMD Geode™ 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-pixel
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?