User guide

15–8 Chapter 15: Deinterlacer MegaCore Function
Functional Description
Video and Image Processing Suite January 2013 Altera Corporation
User Guide
Handling of Avalon-ST Video Control Packets
When buffering is used, the Deinterlacer MegaCore function stores non-image data
packets in memory as described in “Buffering of Non-Image Data Packets in
Memory” on page 3–21.
Control packets and user packets are never repeated and they are not dropped or
truncated as long as memory space is sufficient. This behavior also applies for the
parameterizations that do not use buffering in external memory; incoming control
and user packets are passed through without modification.
In all parameterizations, the Deinterlacer MegaCore function generates a new and
updated control packet just before the processed image data packet. This packet
contains the correct frame height and the proper interlace flag so that the following
image data packet is interpreted correctly by following MegaCore functions.
1 The Deinterlacer uses 0010 and 0011 to encode interlacing values into the Avalon-ST
Video packets it generates. These flags mark the output as being progressive and
record information about the deinterlacing process. (Refer to Table 3–4 on page 3–8.)
The interlacing is encoded as 0000 when the Deinterlacer is passing a progressive
frame through.
Avalon-ST Video Protocol Parameters
The Deinterlacer MegaCore function can process streams of pixel data of the types
listed in Table 15–1.
Stall Behavior and Error Recovery
While the bob algorithm (with no buffering) is producing an output frame it
alternates between simultaneously receiving a row on the input port and producing a
row of data on the output port, and just producing a row of data on the output port
without reading any data from the input port.
The delay from input to output is just a few clock cycles. While a field is being
discarded, input is read at the maximum rate and no output is generated.
Table 15–1. Deinterlacer Avalon-ST Video Protocol Parameters
Parameter Value
Frame Width Run time controlled. (Maximum value specified in the parameter editor.)
Frame Height Run time controlled. (Maximum value specified in the parameter editor.)
Interlaced /
Progressive
Interlaced input, Progressive output (plus optional passthrough mode for progressive input).
Bits per Color Sample Number of bits per color sample selected in the parameter editor.
Color Pattern
One, two or three channels in sequence or in parallel as selected in the
parameter editor. For example, for three channels in sequence where , 
, and
 can be any color plane:
When the compatibility mode for subsampled 4:2:2 Y’CbCr data is turned on,
the motion-adaptive deinterlacer expects the data as either 4:2:2 parallel data
(two channels in parallel) or 4:2:2 sequential data (two channels in sequence):
γβα
Cb Cr
YY
CrCb YY