Channel Class

Accessing a physical CSDB channel requires a handle to the channel.

A channel handle is a reference to a channel holding a physical resource (port). The channel handle is the first argument to be passed to many MXF channel oriented functions.

To get the handle to a CSDB physical port regardless of the devices installed, use the mxfModuleChannelGet() function by specifying the physical port index.

The mxfModuleChannelAllGet() function with the chnClass argument MXF_CLASS_CSDB can also be used.

If MXF_DEVICE_ALL is specified with mxfSystemDeviceAllGet() function, all handles of detected devices are returned.

Protocol selection is made with Channel Class attribute.

{
HMXF_SERVER server=0;
HMXF_DEVICE device;
HMXF_MODULE module;
HMXF_CHANNEL rx[4];
uint32 rc;
uint64 deviceCount;
uint64 moduleCount;
uint64 channelCount;
uint64 device     = MXF_DEVICE_ALL;          // All devices
uint64 moduleType = MXF_MODULE_ASYNC_EH;     // ASYNC-ENHANCED module
uint64 chnClass   = MXF_CLASS_CSDB;// CSDB channel class
uint64 subClass   = MXF_SCLASS_RX_CHANNEL;   // RX channel

   // Connects to the local server
   rc = mxfServerConnect("0.0.0.0", "", "", FALSE, &server);
   if (rc)
   {
      printf("Error connection 0x%08lx", rc);
      return rc;
   }
   // Inits MXF library
   rc = mxfSystemInit(server);
   if (!rc)
   {
      // Gets the device handle
      rc = mxfSystemDeviceAllGet(server, device, 1, &deviceCount, &device);
      if (!rc)
      {
         // Gets the module handle
         rc = mxfDeviceModuleAllGet(device, moduleType, 1, &moduleCount, &module);

         // Gets the channel handle
         if (!rc)
            rc = mxfModuleChannelAllGet(module, chnClass, subClass, 4, &channelCount, rx);
       }
   }
}

Changing channel class

Depending on the module type, a CSDB channel can by default be configured to another channel class. To configure a channel to CSDB, an initialization callback set with mxfSystemInitAttributeUint64CallbackHandler() function must be used.
Since MXF 4.5.2, it is now possible to change the channel class by using mxfAttributeUint64Set() with KMXF_CHANNEL_CLASS attribute instead of using the initialization handler.
It is a good programming practice to not rely on default channel class value (or any other attributes for that matter) and set it to the desired value.