Transmission with Absolute Timing

The option MXF_TXAPERIODIC_FLAG_ABSOLUTE_START_TIME is used for starting a transmission at a specific start time in the future.

csdb_aperiodic.c
In this example, the transmission start time is based on the device clock + 100ms in the future, then the records are sent back-to-back.

#define BUFFER_SIZE     4096 // 4KB
#define MAX_TX_RECORDS_TO_TRANSMIT 8
#define BLOCKCOUNT 6

HMXF_SERVER server;
HMXF_DEVICE device;
HMXF_CHANNEL txChannel;
HMXF_BUFFER  txBuffer=0;
HMXF_CSDB_DATAREC *recCsdb=NULL;
HMXF_CSDB_DATAREC *rec;
uint32 record;
uint64 delay100ms = 100000;
uint32 rc;
uint64 currentTime;

   ...

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

   // Allocate Aperiodic TX static buffer for HIGH priority queue
   if (!rc)
      rc = mxfTxAperiodicBufferAlloc(txChannel, MXF_TXAPERIODIC_PRIORITY_HIGH, BUFFER_SIZE, &txBuffer, NULL);

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

  // Get the current time
  if(!rc)
     rc = mxfDeviceTimerGet(device, &currentTime);

   // Set the record
   rec = recCsdb;
   for (record=0; record < MAX_TX_RECORDS_TO_TRANSMIT && !rc; record++)
   {
      if(record == 0)
      {
         // Set sync block
         rec->timeTag = 0;
         rec->control = 0;
         rec->repeatCount = 1;
         rec->reserved = 0;
         for(dataIdx=0; dataIdx<BLOCKCOUNT; dataIdx++)
            rec->data[dataIdx] = 0xA5;
      }
      else
      {
         // Set each record: LABEL=6, SI=1
         rec->timeTag = 0;
         rec->control = 0;
         rec->repeatCount = 1;
         rec->reserved = 0;
         rec->data[0] = 6;
         rec->data[1] = 1;
         for(dataIdx=2; dataIdx<BLOCKCOUNT; dataIdx++)
            rec->data[dataIdx] = (uint8)record;
      }

      mxfCSDBNextDataRecordPtrGet(rec, &rec);
   }

   // Transmit the array of records
   if (!rc)
      rc = mxfCSDBTxAperiodicWrite(txBuffer, MXF_TXAPERIODIC_FLAG_ABSOLUTE_START_TIME, currentTime+delay100ms, MAX_TX_RECORDS_TO_TRANSMIT, recCsdb);

   if (recCsdb)
      free(recCsdb);

   ...