AMD Geode SC1201 - Manual (Page 341)

AMD Geode™ SC1200/SC1201 Processor Data Book 341
Video Processor Module - Video Processor Registers - Function 4 32579B
10:0 VID_Y_START (Video Y Start Position). Represents the vertical start position of the video window. This value is calculated
according to the following formula:
Value = Desired screen position + (V_TOTAL – V_SYNC_END) + 1.
Offset 10h-13h Video Upscale Register (R/W) Reset Value: 00000000h
Provides horizontal and vertical upscale factors of the window.
31:30 Reserved.
29:16 VID_Y_SCL (Video Y Scale Factor). Represents the vertical upscale factor of the video window according to the following
formula:
VID_Y_SCL = 8192 * (Ys - 1) / (Yd - 1)
where:
Ys = Video source vertical size in pixels
Yd = Video destination vertical size in pixels
Note: Upscale factor must be used. Yd is equal or bigger than Ys. If no scaling is intended, set to 2000h. The actual scale
factor used is VID_Y_SCL/8192, but the formula above fits a given source number of lines into a destination win-
dow size.
Note: When progressive mixing/blending is programmed (F4BAR0+Memory Offset 4Ch[9] = 0) and the video data is
interlaced, this register should be programmed to 1000h to double the vertical lines,
15:14 Reserved.
13:0 VID_X_SCL (Video X Scale Factor). Represents horizontal upscale factor of the video window according to the following
formula:
VID_X_SCL = 8192 * (Xs - 1) / (Xd - 1)
where:
Xs = Video source horizontal size in pixels
Xd = Video destination vertical size in pixels
Note: Upscale factor must be used. Xd is equal or bigger than Xs. If no scaling is intended, set to 2000h. The actual scale
factor used is VID_X_SCL/8192, but the formula above fits a given source number of pixels into a destination win-
dow size.
Offset 14h-17h Video Color Key Register (R/W) Reset Value: 00000000h
Provides the video color key. The color key can be used to allow irregular shaped overlays of graphics onto video, or video onto graphics,
within a scaled video window.
31:24 Reserved.
23:0 VID_CLR_KEY (Video Color Key). The video color key is a 24-bit RGB or YUV value.
• If the COLOR_CHROMA_SEL bit (F4BAR0+Memory Offset 04h[20]) = 0:
— The video pixel is selected within the target window if the corresponding graphics pixel matches the color key. The
color key in an RGB value.
• If the COLOR_CHROMA_SEL bit (F4BAR0+Memory Offset 04h[20]) = 1:
— The video pixel is selected within the target window only if it (the video pixel) does not match the color key. The color
key is usually an RGB value. However, if both the CSC_for VIDEO and GV_SEL bits (F4BAR0+Memory Offset 4Ch
bits 10 and 13, respectively) are programmed to 0, the color key is a YUV value (i.e., video is not converted to RGB).
The graphics or video data being compared can be masked prior to the compare via the Video Color Mask register
(described in F4BAR0+Memory Offset 18h).
Offset 18h-1Bh Video Color Mask Register (R/W) Reset Value: 00000000h
Provides the video color mask. This value is used to mask bits of the graphics or video stream being compared to the video color key
(described in F4BAR0+Memory Offset 14h). It can be used to allow a range of values to serve as the color key.
31:24 Reserved.
23:0 VID_CLR_MASK (Video Color Mask). This mask is a 24-bit value. Zeros in the mask cause the corresponding bits in the
graphics or video stream to be ignored.
Table 7-9. F4BAR0+Memory Offset: Video Processor Configuration Registers (Continued)
Bit Description