sync_byte [MPEG-2 Semantics]
the sync_byte is the first byte in an MPEG-2 transport packet. It is an 8-bit unsigned integer value that is used by receivers to syncronize each received packet.
Each transport stream sync_byte has the value 71 / 0x47, regardless of the MPEG user. However, some sync bytes used in ATSC Distributed Transmission might have the value of 184 / 0xC8, which is AND (71 / 0x47).