National Instruments NI CVS-1450 Series - Manual (Page 11)

Chapter 1 NI CVS-1450 Series Overview
© National Instruments Corporation 1-3 NI CVS-1450 Series User Manual
Available Camera Bandwidth
The IEEE 1394 bus provides a fixed amount of bandwidth that is shared
among the three IEEE 1394a ports on the CVS-1450 device. These ports
provide direct connection for up to three DCAM-compliant IEEE 1394
cameras, depending on the amount of bandwidth each camera requires.
Higher frame rates and larger image sizes require a higher data transfer rate
and use more bandwidth.
Table 1-1 shows the maximum number of cameras the CVS-1450 device
supports for three common video formats. Use this table as a guide when
determining the combination of cameras to use in your application.
Note Bandwidth calculations described in Table 1-1 do not include software decoding of
YUV images to RGB. This conversion time is dependent on processor speed.
By triggering your cameras at a frame rate slower than those rates listed in
Table 1-1, you can operate more cameras simultaneously. If the camera
combination exceeds the amount of available bandwidth, the software
returns an Insufficient Resources error.
Table 1-1. Available Camera Bandwidth
Video Format
Frames
per Second
Maximum Number
of Cameras for
Simultaneous Operation
640
× 480
8-bits/pixel mono
30 3
60 1
100 1
640
× 480 YUV
(4:2:2)
16-bits/pixel color
15 3
30 1
1024
× 768
16-bits/pixel mono
7.5 2
15 1