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Input2
Input1
alpha
Blended Output
(A)
Internal Modules
76
SPRUHI7A – December 2012 – Revised June 2016
Copyright © 2012–2016, Texas Instruments Incorporated
High-Definition Video Processing Subsystem (HDVPSS)
1.2.3.3.4 Graphics Windows
These windows are formed in the corresponding GPRX modules by configuring below:
GRPX
→
frame_display_attributes.frame_height = Display_Height of VENC associated with corresponding
Grpx
GRPX
→
frame_display_attributes.frame_width = Display_Width of VENC associated with corresponding
Grpx
The origin of a Grpx region input in the window (x,y) is configured as below:
GRPX
→
region_display_attributes.disp_pos_x = x
GRPX
→
region_display_attributes.disp_pos_y = y
Background color for Grpx window is transparent and carries an alpha value of zero. It gets the
background color set by COMP
→
back_clr at the time of composition.
The alpha value configuration for blending is explained in GRPX module. Blend type for a region is
selected using following bitfield:
GRPX
→
region_display_attributes.Disp_blend_cfg
The priority level of a graphics region is set, in corresponding region, using the bitfield mentioned below:
GRPX
→
region_display_attributes.Disp_prior
1.2.3.4
Blender
A Blender in the COMP module works as mentioned in
Figure 1-33. Blender Diagram
A
Input2 is tied to 0 for the SD Blender.
When two input sources, say input1 and input2, are blended, the resulting source is calculated as follows:
Blended Output =(a)* (1-a)*input2
if input1 is top layer and input2 is
bottom layer
=(1-b)* (b)*input2
if input2 is top layer and input1 is
bottom layer