User guide

Table Of Contents
Chapter 6: Alpha Blending MegaCore Function 6–5
Parameter Settings
January 2013 Altera Corporation Video and Image Processing Suite
User Guide
The latency is measured with the assumption that the MegaCore function is not being
stalled by other functions on the data path (the output ready signal is high).
1 The latency associated with the initial buffering phase, when a MegaCore function
first receives video data, is not included.
Parameter Settings
Table 63 lists the Alpha Blending Mixer MegaCore function parameters.
Table 6–2. Alpha Blending Mixer Latency
Mode Latency
All modes O (cycles)
(1)
Note to Table 62:
(1) O refers to a small number of clock cycles, and is not of zero value.
Table 6–3. Alpha Blending Mixer Parameter Settings
Parameter Value Description
Maximum layer
width
32–2600, Default = 1024
Choose the maximum image width for the layer background in pixels. No
layer width can be greater than the background layer width. The
maximum image width is the default width for all layers at start-up.
Maximum layer
height
32–2600, Default = 768
Choose the maximum image height for the layer background in pixels. No
layer height can be greater than the background layer height. The
maximum image height is the default height for all layers at start-up.
Bits per pixel per
color plane
4–20, Default = 8 Choose the number of bits per pixel (per color plane).
Number of color
planes in sequence
1–3
Choose the number of color planes that are sent in sequence over one
data connection. For example, a value of 3 for R'G'B' R'G'B' R'G'B'.
Number of color
planes in parallel
1–3 Choose the number of color planes in parallel.
Number of layers
being mixed
2–12
Choose the number of image layers to overlay. Higher number layers are
mixed on top of lower layer numbers. The background layer is always
layer 0.
Alpha blending On or Off
When on, alpha data sink ports are generated for each layer (including an
unused port
alpha_in_0
for the background layer). This requires a
stream of alpha values; one value for each pixel. When off, no alpha data
sink ports are generated, and the image layers are fully opaque.
Alpha bits per pixel 2, 4, 8 Choose the number of bits used to represent the alpha coefficient.