User`s manual

Reference Manual 137
Bitmap Stored in SDRAM
For every pixel in the bitmap, 4 bit data will be used to describe
OSD behavior of the pixel. Format of BITMAP in SDRAM is:
P(x, y) means 4 bit data of pixel at column x and line y.
OSD Pixel Color (4-bit OSD Data)
For every pixel, there are 4 bits to present the OSD behavior. It
means:
For mode 0, the algorithm is:
For mode 1, the algorithm is:
bit 0 bit 31
dword 0 P(0,0) P(0,1) P(0,2) P(0,3) P(0,4) P(0,5) P(0,6) P(0,7)
. P(1,0) P(1,1) P(1,2) P(1,3) P(1,4) P(1,5) P(1,6) P(1,7)
. ……………………
. P(15,0) P(15,1) P(15,2) P(15,3) P(15,4) P(15,5) P(15,6) P(15,7)
. P(0,8) P(0,9) P(0,10) P(0,11) P(0,12) P(0,13) P(0,14) P(0,15)
. P(1,8) P(1,9) P(1,10) P(1,11) P(1,12) P(1,13) P(1,14) P(1,15)
. ……………………
Bit(s) Description
[3]
OSD mode
0 – Background blending
1 – Foreground blending
[2:0] Alpha blending level (0 - 7)