SVS-Vistek CameraLink svs16000, Руководство пользователя

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Users Manual Area Scan Cameras SVSGigE Page 70
Users Manual –svs11002 and svs16000
© SVS-VISTEK GmbH
Programming interface
When opening a camera, an application is supposed to check whether the camera
streams already in multicast mode using the function:
Camera_getMulticastMode()
The multicast mode will be one of the following items:

MULTICAST_MODE_NONE

MULTICAST_MODE_LISTENER

MULTICAST_MODE_CONTROLLER
If the camera is already streaming in multicast mode then the application can connect
to the camera but as listening application (
MULTICAST_MODE_LISTENER
).
Otherwise, if a camera is still idle (
MULTICAST_MODE_NONE
), an application can
request for a multicast session by switching a camera’s mode to “multicast”
(
MULTICAST_MODE_CONTROLLER
) before opening the streaming channel. The
appropriate function is:
Camera_setMulticastMode()
Afterwards the application might check the automatically generated IP for the
multicast group in the “232.x.x.x” range using the following function:
Camera_getMulticastGroup()
Packet size consideration
A controlling application will usually open a streaming channel at the highest available
packet size, e.g. 16112 bytes. If another application connects to that already running
streaming channel then a packet size problem may arise if the listening application
has not at least the packet size available that the image stream is currently working
with.
Therefore a controlling application is supposed to limit the packet size of the image
data stream to a value which allows all intended listening applications to connect to
that image stream.
If a listening application encounters a packet size problem, it will usually receive the
start and stop packages of each image since those are of small size. This causes a
progress of image statistics like image counter, however, there will be no image data
(image payload) available. The packet size has to be reduced in this case by the
controlling application in order to allow all listening applications for receiving all image
payload data properly.
An application might choose to display a message to the user in the above described
case like “
Image payload missing. Multicast packet size too big?
“ as it was done in the
“SVGigE_Example.VC8” application in the SDK.