IPSR-VIDEO Altera, IPSR-VIDEO Datasheet - Page 85

• Manufacturer Part Number: IPSR-VIDEO
• Description: RENEWAL Of IPS-VIDEO
• Manufacturer: Altera
• Series: IP Suitesr

Specifications of IPSR-VIDEO

• Software Application: IP CORE, SUITES
• Supported Families: Arria GX, Cyclone II, HardCopy II, Stratix II
• Features: Common Avalon Streaming (Avalon-St) Interface And Avalon-St Video Protocol
• Core Architecture: FPGA
• Core Sub-architecture: Arria, Cyclone, Stratix
• Rohs Compliant: NA
• Lead Free Status / RoHS Status: na

Chapter 5: Functional Descriptions
Alpha Blending Mixer
Table 5–3. Alpha Blending Mixer Avalon-ST Video Protocol Parameters
January 2011 Altera Corporation
Frame Width
Frame Height
Interlaced / Progressive
Bits per Color Sample
Color Pattern (din and
dout)
Color Pattern (alpha_in)
Parameter
1
It is not necessary to send control packets to the ports of the alpha channels. The
width and height of each alpha layer are assumed to match with the dimensions of the
corresponding foreground layer. The Alpha Blending Mixer MegaCore function
should recover cleanly if there is a mismatch although there may be throughput issues
at the system-level if erroneous pixels have to be discarded. All non-image data
packets (including control packets) are ignored and discarded just before the
processing of a frame starts.
The valid range of alpha coefficients is 0 to 1, where 1 represents full translucence, and
0 represents fully opaque.
For n-bit alpha values (RGBAn) coefficients range from 0 to 2
(2
255 => 1, 254 => 254/256, 253 => 253/256 and so on.
The value of an output pixel O
deduced from the following recursive formula:
where p
and disabled layers are skipped. The function does not use alpha values for the
background layer (a
instantiated in SOPC Builder or the parameter editor.
All input data samples must be in unsigned format. If the number of bits per pixel per
color plane is N, then each sample consists of N bits of data which are interpreted as
an unsigned binary number in the range [0, 2
by the Alpha Blending Mixer MegaCore function are also in the same unsigned
format.
The Alpha Blending Mixer MegaCore function can process streams of pixel data of the
types shown in
n
–1) as 1, and all other values as (Alpha value)/2
O
O
Run time controlled. (Maximum value specified in the parameter editor.)
Run time controlled. (Maximum value specified in the parameter editor.)
Progressive. Interlaced input streams are accepted but they are treated as progressive inputs.
Consequently, external logic is required to synchronize the input fields and prevent the mixing
of F0 fields with F1 fields.
Number of bits per color sample selected in the parameter editor (specified separately for
image data and alpha blending).
One, two or three channels in sequence or in parallel as selected in the
parameter editor. For example, if three channels in sequence is selected where
A single color plane representing the alpha value for each pixel:
N
0
,
= p
= (1 – a
N
,
is the input pixel for layer N and a
and
0
N
)p
can be any color plane:
Table
N
+ a
0
) and you should tie the alpha0 port off to 0 when the core is
N
5–3.
O
N
– 1
N
, where N is the maximum number of layers, is
Value
N
N
is the alpha pixel for layer N. Consumed
– 1]. All output data samples produced
n
. For example, 8-bit alpha value
Video and Image Processing Suite User Guide
n
–1. The model interprets
α
β
A
γ
5–5