Pike
Technical
Manual
V5.2.3
253
How does bandwidth affect the frame rate?
How
does
bandwidth
affect
the
frame
How does bandwidth affect the frame rate?
In
some
modes
the
IEEE1394b
bus
limits
the
attainable
frame
rate.
According
to
the
1394b
specification
on
isochronous
transfer,
the
largest
data
payload
size
of
8192
bytes
per
125
µs
cycle
is
possible
with
bandwidth
of
800
Mbit/s.
In
addition,
there
is
a
limitation,
only
a
maximum
number
of
65535
(2
16
-1)
packets
per
frame
are
allowed.
The
following
formula
establishes
the
relationship
between
the
required
Byte_Per_Packet
size
and
certain
variables
for
the
image.
It
is
valid
only
for
Format_7.
If
the
value
for
BYTE_PER_PACKET
is
greater
than
8192
(the
maximum
data
payload),
the
sought-after
frame
rate
cannot
be
attained.
The
attainable
frame
rate
can
be
calculated
using
this
formula:
(Provision:
BYTE_PER_PACKET
is
divisible
by
4):
ByteDepth
based
on
the
following
values:
Example formula for the monochrome camera
Mono16,
1392
×
1040,
30
fps
desired
Formula 20: Byte_per_Packet calculation (only Format_7)
Formula 21: Maximum frame rate calculation
Mode
bit/pixel
byte per pixel
Mono8,
Raw8
8
1
Mono16,
Raw16
16
2
YUV4:2:2
16
2
YUV4:1:1
12
1.5
RGB8
24
3
Table 132: ByteDepth
BYTE_PER_PACKET
frame rate[1/s]
AOI_WIDTH
AOI_HEIGHT
ByteDepth [byte]
125 [μs]
=
frame rate
BYTE_PER_PACKET [byte]
AOI_WIDTH
AOI_HEIGHT
ByteDepth [byte]
125 [μs]
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