Basic Sampling

The way to setup a basic sampling receive application is as follows:

• A receive channel must be obtained using the mxfModuleChannelGet() or mxfModuleChannelAllGet() functions using MXF_SCLASS_RXSAMPLING_SRV subclass.
• The Sampling buffer must be allocated using the mxfRxSamplingBufferAlloc() function.
• A sampling kill time can be set with the mxfRxSamplingKilltimeSet() function to allow the invalidation of the last reception if the data is too old.
• Start the sampling using the mxfRxSamplingStart() function.
• Sampling read can be performed by using the mxfCSDBRxSamplingRead() or mxfCSDBRxSamplingSingleRead() functions.

The MXF_CSDB_SAMPREC structure must be used for reading a CSDB message with the sampling service.

Example

csdb_rx_sampling.c
The example below shows how to implement a CSDB sampling receive application.

#define BUFFER_SIZE     4096 // 4KB
#define LABEL           0x3
#define BLOCKCOUNT      6

HMXF_SERVER server;
HMXF_CHANNEL rxChannel;
HMXF_BUFFER  rxBuffer;
MXF_CSDB_SAMPREC *hostBuffer=NULL;
MXF_CSDB_SAMPREC *recSamp;
uint64 label=0xA5;
uint64 msgsCount, bytesCount;
uint64 j;
uint32 rc;

   ...

   // Set timebase to 64-bit microseconds
   if (!rc)
      rc = mxfSystemTimeBaseSet(server, MXF_TIMEBASE_DEVICE_USEC);

   // Allocate host buffer
   if(!rc)
   {
      hostBuffer = (MXF_CSDB_SAMPREC *)malloc(BUFFER_SIZE);
      if(!hostBuffer)
         rc = MAXT_ERROR_MEM;
   }

   // Allocate RX sampling buffer
   if(!rc)
      rc = mxfRxSamplingBufferAlloc(rxChannel, BUFFER_SIZE, &rxBuffer, NULL);

   // Filters out a specific label/si
   if (!rc)
      rc = mxfCSDBRxSamplingMsgSelectSet(rxBuffer, MXF_MSG_DESELECT, 1, &label);

    // Sets sampling kill time to 1 second.
    if (!rc)
        rc = mxfRxSamplingKilltimeSet(rxBuffer, 1000000);      

   // Starts sampling
   if(!rc)
      rc = mxfRxSamplingStart(rxBuffer);

   ...

   // Reads and displays records
   if(!rc)
   {
      rc = mxfCSDBRxSamplingRead(rxBuffer, MXF_RXSAMPLING_FLAG_DEFAULT, 0, BUFFER_SIZE, &msgsCount, &bytesCount, hostBuffer);
      if(!rc)
      {
         printf("Read %llu messages\n\r", msgsCount);
         recSamp = (MXF_CSDB_SAMPREC*)hostBuffer;
         for (j=0; !rc && j<msgsCount; j++)
         {
            printf("%02llu: Timetag=%016llu: CSDB data=[ ", j, recSamp->timeTag);
            for (dataIndex=0; dataIndex<BLOCKCOUNT; dataIndex++)
               printf("0x%02X ", recSamp->data[dataIndex]);
            printf("]\n\r");

            mxfCSDBNextSamplingRecordPtrGet(recSamp, &recSamp);
         }
      }
   }

   ...