User guide

Chapter 18: Frame Buffer MegaCore Function 18–5
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 18–3 lists the Frame Buffer parameters.
Table 18–2. Latency
Mode Latency
All modes 1 frame +O lines
(1)
Note to Table 18–2:
(1) O refers to a small number of clock cycles, and is not of zero value.
Table 18–3. Frame Buffer Parameter Settings (Part 1 of 2)
Parameter Value Description
Maximum image width
32–2600,
Default = 640
Specify the maximum frame width.
Maximum image height
32–2600,
Default = 480
Specify the maximum frame height. In general, this value
should be set to the full height of a progressive frame.
However, it can be set to the height of an interlaced field for
double-buffering on a field-by-field basis when the support
for interlaced inputs has been turned off.
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 in sequence.
Number of color planes in parallel 1–3 Choose the number of color planes in parallel.
Frame dropping On or Off Turn on to allow frame dropping.
Frame repetition On or Off Turn on to allow frame repetition.
Drop invalid fields/frames On or Off
Turn on to drop image data packets whose length is not
compatible with the dimensions declared in the last control
packet.
Run-time control for the writer thread On or Off Turn on to enable run-time control for the write interfaces.
Run-time control for the reader
thread
On or Off Turn on to enable run-time control for the read interfaces.
Support for locked frame rate
conversion
(1)
,
(2)
On or Off
Turn on to synchronize the input and output frame rates
through an Avalon-MM slave interface.
Support for interlaced streams On or Off
Turn on to support consistent dropping and repeating of
fields in an interlaced video stream. This option must not
be turned on for double-buffering of an interlaced input
stream on a field-by-field basis.
Number of packets buffered per
frame
(3)
0–32
Specify the maximum number of non-image, non-control,
Avalon-ST Video packets that can be buffered with each
frame. Older packets are discarded first in case of an
overflow.