I'm trying to access a GigE camera using the Genicam reference implementation by trying to look at the online resources and existing existing resources (aravis, harvesters) and follow the GenTL standard using the SNFC which every Genicam compatible camera supports. The producer I'm currently using is from Basler since the camera I have here is from them.
/* I wrapped the Genicam classes with my own. Here are the relevant parts */
tl = new GenicamTransportlayer("/opt/pylon/lib/gentlproducer/gtl/ProducerGEV.cti");
if0 = tl.getFirstInterface();
dev0 = if0.getFirstDevice();
ds = dev0.getFirstDataStream();
I'm able to connect to the System, Interface, Device, DataStream, connect the nodemaps and am now trying to set up the buffers for acquisition. To do so I need to get the maximum payload size from the camera. The GenTL standard document standard says, I need to query it from the DataStream module using
boolean definesPayloadSize = ds.getInfoBool8(StreamInfoCommand.STREAM_INFO_DEFINES_PAYLOADSIZE);
which gives me 0 or false. The producer MAY provide a PayloadSize feature which can be queried using
ds.getInfoSizet(StreamInfoCommand.STREAM_INFO_PAYLOAD_SIZE);
which is obviously also 0 and with being a may I cannot rely on it. The standard further tells me if both fail, I need to inquire via the remote devices NodeMap to read the PayloadSize:
long payloadSizeFromRemoteMap = dev0.remoteMap.getIntegerNode("PayloadSize").getValue();
This gives me 0 too. The standard goes on that if the producer does not implement an interface standard (whatever this means?), the required payload size has to be queried via the producer using the StreamInfo Commands which also fails (GenTL maps the constant STREAM_INFO_PAYLOAD_SIZE to 7 which produces a BufferTooSmallException on the System port).
At this point I'm confused on what to do. Most of my nodes are locked (I can overwrite TLParamsLocked but still cannot change parameters, eg, execute a load of the default parameter set) so I cannot set Width/Height/ImageFormat to infer the PayloadSize:
/* Trying to set a default configuration fails */
IEnumeration userSetSelector = dev0.remoteMap.getEnumerationNode("UserSetSelector");
log.debug("Loading Feature set: " + userSetSelector.getEntries().get(0).getName());
// Prints: Loading Feature set: EnumEntry_UserSetSelector_Default
userSetSelector.setValue("Default");
dev0.remoteMap.getCommandNode("UserSetLoad").execute();
// AccessException: Node is not writable. : AccessException thrown in node 'UserSetLoad' while calling 'UserSetLoad.Execute()' - Node is not writable.
Without knowing the size of the buffers I cannot continue. How can I infer the PayloadSize to set them up?
It turns out, the reference implementation indeed does what I expected. I had a port set up wrong which did not error out but also acted like a black hole for the transport layer. Fixing this subtle error allowed me to obtain the PayloadSize via all described ways above without any problems.