 Each FC frame begins with a 4 byte ordered set, called an SOF (Start of Frame), and ends with an EOF (End of Frame), additionally, a 4 byte CRC is included for data integrity.The payload of the first FC frame in a sequence contains embedded header data that accompanies each video image.Each XGA video line requires 3072 bytes, which exceeds the maximum FC payload length, so each line is divided into two FC frames.