Coaxlink Programmer's GuideGenTL
The real point of the system module is to list the interfaces (or frame grabbers) present in the system. The most
important functions of the system module are TLGetNumInterfaces (to retrieve the number of frame grabbers in
the system) and TLOpenInterface (to get access to one of the frame grabbers).
Interface module
The GenTL standard calls frame grabbers interfaces. The system module has one child interface for each frame
grabber: if there are 2 Coaxlink cards in the computer, the system module will have two child interfaces.
Each interface represents a frame grabber. Global frame grabber features such as digital I/O lines belong in the interface
module. This means that the GenApi features controlling the I/O lines are attached to the interface.
Each interface also acts as parent to one or several devices. The most important functions of the interface module are
IFGetNumDevices (to retrieve the number of cameras that can be connected to the interface) and IFOpenDevice
(to get access to one of the devices).
Device module
The GenTL standard uses the terms device and remote device for two related but different concepts. A remote device
is a real camera, physically connected to a frame grabber. This is different from the device module we describe here.
The device module is the module that contains the frame grabber settings relating to the camera. This includes things
like triggers and strobes.
The device module also acts as parent to one data stream, and can be viewed as the sibling of the remote device.
The most important functions of the device module are DevOpenDataStream (to get access to the data stream) and
DevGetPort (to get access to the remote device).
Data stream module
The data stream module handles buffers. During acquisition runs, images are sent from the camera to the frame
grabber, which transfers them to memory buffers allocated on the host computer. The data stream module is where
image acquisition occurs. It is where most of the functionality resides.
Buffer handling is very flexible. Any number of buffers can be used. Buffers are either in the input queue, in the output
queue, or temporarily unqueued. The application decides when empty buffers are queued (to the input FIFO), and
when filled buffers are popped (from the output FIFO).
Buffer module
The buffer module simply represents a memory buffer given to a parent data stream. Useful metadata is associated to
buffers. This includes the image width, height, pixel format, timestamp... These are retrieved through info commands
(see BUFFER_INFO_CMD_LIST in the standard GenTL header file).
The buffer module is the only module that doesn't have read/write port functions; it doesn't have GenApi features.
GenTL API
GenTL makes it possible to detect, control and use all camera and frame grabber features, but its usage is tedious:
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